The truth about Solar Panel performance and temperature

How does the Aussie heat affect your solar panel performance?

One of the main factors that makes Solar Power so popular over here (apart from the Aussie Pollies throwing wads of money at in in the form of Solar rebates and Solar Feed In Tariffs) is the fact that the Sun is so damn strong down here.

It’s not rocket science to work out why Solar Power hasn’t really taken off in less sunny climes like my homeland; grey, drizzly old England.

In fact the same 1.5kW system on a roof of my Mum’s quaint cottage in Northern England will produce 45% less energy than if it was on my roof here in Sunny Adelaide.

So does that mean the more sun the better, when it comes to generating Solar Power?

That would kind of make sense, right?

Unfortunately, as with most things in this life, it is a bit more complicated than that.

In fact when it comes to solar power you can have too much sun.


Say What?!?

The problem is, most solar panels’ power outputs start to degrade if the temperature of the panel goes over about 25°C.

This is why, if you look at the specification label on a solar panel, most manufacturers quote the solar power output at a panel temperature of 25degC.

So does that mean that if it is 25°C outside and a clear blue sky then your panels will be performing to their rated output?

Err… no.

Because, if the air temperature outside is 25°C, that dark solar panel baking on your roof is going to be closer to 50°C.

So how much solar power will you be losing on a 25°C day if the panel manufacturer has quoted power output at a solar panel temperature of 25°C?

To work that out we need to know the solar panel’s “Max Power Temperature Coefficient”, which should be on the solar panel’s specification sheet.


A typical value for this is 0.4% per °C.

Which means that for every degree that the solar panel is above 25°C the  power will fall 0.4%.

So on a cool 25°C day where the panel is cooking at 50°C, you will be losing 10% of your solar power.

Here’s the calc:

0.4% x (50°C -25°C) = 0.4% x 25°C = 10%


And on days when the mercury breaks 40°C you can be losing close to 20% of your solar power.

Which is why you can often find that on the hottest days those solar panels on your roof are actually producing less solar power than usual.

If you are looking for solar panels that perform well in hot Australian weather, then here’s a list of some popular solar panel brands and their temperature coefficients, the best performing (temperature-wise) are at the top. (If I’ve left out your favourite panel – let me know via the commments and I’ll get it added!)

Manufacturer Model Temperature Coefficient (%/°C)
UniSolar PVL-68 -0.21
UniSolar PVL-124 -0.21
UniSolar PVL-128 -0.21
UniSolar PVL-136 -0.21
UniSolar PVL-144 -0.21
Sanyo HIT-195DA3 -0.29
Sanyo HIT-190DA3 -0.30
Sanyo HIT-205NKHA1 -0.34
Sanyo HIT-210NKHA1 -0.34
Sanyo HIT-215NKHA1 -0.34
SunPower SPR-210-BLK -0.38
SunPower SPR-215-WHT -0.38
SunPower SPR-225-BLK -0.38
SunPower SPR-230-WHT -0.38
SunPower SPR-305-WHT -0.38
SunPower SPR-310-WHT -0.38
SunPower SPR-315-WHT -0.38
SunPower SPR-318E-WHT-D -0.38
Canadian CS6A-150PE -0.42
Canadian CS6A-160PE -0.42
Canadian CS6P-170PE -0.42
Kyocera KD135GX-LPU -0.42
CEEG SST 160-72M -0.42
CEEG SST 165-72M -0.42
CEEG SST 170-72M -0.42
CEEG SST 265-72M -0.42
CEEG SST 175-72M -0.42
CEEG SST 270-72M -0.42
CEEG SST 180-72M -0.42
CEEG SST 275-72M -0.42
CEEG SST 280-72M -0.42
CEEG SST 235-60M -0.42
CEEG SST 185-72M -0.42
CEEG SST 285-72M -0.42
CEEG SST 240-60M -0.42
CEEG SST 245-60M -0.42
CEEG SST 250-60M -0.42
Canadian CS6A-160P -0.43
Canadian CS6A-170P -0.43
Canadian CS6A-180P -0.43
Canadian CS6P-180PE -0.43
Canadian CS6P-190PE -0.43
Canadian CS6P-200P -0.43
Canadian CS6P-200PE -0.43
Canadian CS6P-210P -0.43
Canadian CS6P-220P -0.43
Canadian CS6P-230P -0.43
Evergreen ES-A-200-fa2 -0.43
Evergreen ES-A-200-fa3 -0.43
Evergreen ES-A-205-fa2 -0.43
Evergreen ES-A-205-fa3 -0.43
Evergreen ES-A-210-fa2 -0.43
Evergreen ES-A-210-fa3 -0.43
Evergreen ES-A-215-fa2 -0.43
Evergreen ES-A-215-fa3 -0.43
Hyundai HiS-M215SG -0.43
Hyundai HiS-M194SF -0.43
Hyundai HiS-M218SG -0.43
Hyundai HiS-M197SF -0.43
Hyundai HiS-M221SG -0.43
Hyundai HiS-M200SF -0.43
Hyundai HiS-M224SG -0.43
Hyundai HiS-M203SF -0.43
Hyundai HiS-M227SG -0.43
Hyundai HiS-M206SF -0.43
Hyundai HiS-M230SG -0.43
Hyundai HiS-M209SF -0.43
Hyundai HiS-M212SF -0.43
Kyocera KD205GX-LPU -0.43
Kyocera KD185GX-LPU -0.43
Kyocera KD210GX-LPU -0.43
Kyocera KD215GX-LPU -0.43
Tianwei TW175(35)D -0.43
Tianwei TW180(35)D -0.43
Tianwei TW185(35)D -0.43
Conergy Conergy P 185M -0.44
Day4 Energy Day4 48MC 160 -0.44
Day4 Energy Day4 48MC 165 -0.44
Day4 Energy Day4 48MC 170 -0.44
Day4 Energy Day4 48MC 175 -0.44
Day4 Energy Day4 48MC 180 -0.44
Day4 Energy Day4 48MC 185 -0.44
Day4 Energy Day4 48MC 190 -0.44
Tianwei TW210(28)P -0.44
Tianwei TW215(28)P -0.44
Tianwei TW220(28)P -0.44
Tianwei TW225(28)P -0.44
Tianwei TW230(28)P -0.44
Tianwei TW235(28)P -0.44
Canadian CS5A-160M -0.45
Canadian CS5A-170M -0.45
Canadian CS5A-180M -0.45
Canadian CS5P-220M -0.45
Canadian CS5P-230M -0.45
Canadian CS5P-240M -0.45
Conergy Conergy PowerPlus 220P -0.45
Conergy Conergy Black 225PA -0.45
Conergy Conergy PowerPlus 225P -0.45
Conergy Conergy Black 230PA -0.45
Conergy Conergy P 230PA -0.45
Conergy Conergy P 235PA -0.45
SCHOTT POLY 220 -0.45
SCHOTT POLY 225 -0.45
Solarfun SF190-27-P170 -0.45
Solarfun SF190-27-P175 -0.45
Solarfun SF190-27-P180 -0.45
Solarfun SF190-27-P185 -0.45
Solarfun SF190-27-P190 -0.45
Solarfun SF220-30-P210 -0.45
Solarfun SF220-30-P215 -0.45
Solarfun SF190-27-P195 -0.45
Solarfun SF220-30-P220 -0.45
Solarfun SF190-27-P200 -0.45
Solarfun SF220-30-P225 -0.45
Solarfun SF190-27-P205 -0.45
Solarfun SF220-30-P230 -0.45
Solarfun SF190-27-P210 -0.45
Solarfun SF220-30-P235 -0.45
Solarfun SF220-30-P240 -0.45
Solarfun SF220-30-P245 -0.45
SunPower SER-228P -0.45
Trina TSM-165DA01 -0.45
Trina TSM-170DA01 -0.45
Trina TSM-220PA05 -0.45
Trina TSM-220DA05 -0.45
Trina TSM-175DA01 -0.45
Trina TSM-180DA01 -0.45
Trina TSM-230PA05 -0.45
Trina TSM-230DA05 -0.45
Trina TSM-185DA01 -0.45
Trina TSM-240PA05 -0.45
Trina TSM-240DA05 -0.45
ET Solar ET-P672255 -0.46
ET Solar ET-P654190 -0.46
ET Solar ET-P654195 -0.46
ET Solar ET-P672260 -0.46
ET Solar ET-P660220 -0.46
ET Solar ET-P654200 -0.46
ET Solar ET-P672265 -0.46
ET Solar ET-P660225 -0.46
ET Solar ET-P654205 -0.46
ET Solar ET-P672270 -0.46
ET Solar ET-P660230 -0.46
ET Solar ET-P672275 -0.46
ET Solar ET-P654210 -0.46
ET Solar ET-P672280 -0.46
ET Solar ET-P660235 -0.46
REC REC215PE-US -0.46
REC REC215PE -0.46
REC REC220PE-US -0.46
REC REC220PE -0.46
REC REC225PE-US -0.46
REC REC225PE -0.46
REC REC230PE-US -0.46
REC REC230PE -0.46
REC REC235PE-US -0.46
REC REC235PE -0.46
ET Solar ET-M572165 -0.47
ET Solar ET-M572170 -0.47
ET Solar ET-M572175 -0.47
ET Solar ET-M572180 -0.47
ET Solar ET-M572185 -0.47
Ningbo MP-150WP -0.47
Ningbo MP-155WP -0.47
Ningbo MP-160WP -0.47
Ningbo MP-165WP -0.47
Ningbo MP-170WP -0.47
Ningbo MP-175WP -0.47
Ningbo MP-180WP -0.47
Suntech STP260-24/Vb-1 -0.47
Suntech STP200-18/Ub-1 -0.47
Suntech STP205-18/Ud -0.47
Suntech STP270-24/Vb-1 -0.47
Suntech STP270-24/Vd -0.47
Suntech STP275-24/Vd -0.47
Suntech STP210-18/Ub-1 -0.47
Suntech STP210-18/Ud -0.47
Suntech STP280-24/Vb-1 -0.47
Suntech STP280-24/Vd -0.47
Solarfun SF160-24-P165 -0.48
Solarfun SF160-24-P170 -0.48
Solarfun SF160-24-P175 -0.48
Suntech STP175S-24/Ab-1 -0.48
Suntech STP180S-24/Ab-1 -0.48
Suntech STP185S-24/Ab-1 -0.48
Sharp ND-200UC1 -0.49
Sharp ND-123UJF -0.49
Sharp NE-165UC1 -0.49
Sharp ND-167UC1 -0.49
Sharp ND-208UC1 -0.49
Sharp ND-130UJF -0.49
Sharp NE-170UC1 -0.49
Sharp ND-176UC1 -0.49
Sharp ND-216UC1 -0.49
Sharp ND-U216C1 -0.49
Sharp ND-198UC1 -0.49
Sharp NT-175UC1 -0.49
Sharp ND-220UC1 -0.49
Sharp NU-U180FC -0.49
Sharp ND-224UC1 -0.49
Sharp ND-U224C1 -0.49
Sharp NU-U208FC -0.49
Sharp ND-U230C1 -0.49
Sharp NU-U230F3 -0.49
Sharp ND-187UC1 -0.49
Sharp NU-U235F3 -0.49
Sharp NU-U235F1 -0.49
Sharp NU-U240F1 -0.49
BP BP 3210N -0.50
BP BP 3215B -0.50
BP BP3220T -0.50
BP BP3220N -0.50
BP BP3225T -0.50
BP BP3225N -0.50
BP BP3230T -0.50
BP BP3230N -0.50
BP BP 4175T -0.50
BP BP 4175B -0.50
BP BP 4180T -0.50
REC REC205AE-US -0.50
REC REC210AE-US -0.50
REC REC215AE-US -0.50
REC REC220AE-US -0.50
REC REC225AE-US -0.50
REC REC230AE-US -0.50
Samsung Electronics LPC235SM-02 -0.52
Samsung Electronics LPC238SM-02 -0.52
Samsung Electronics LPC241SM-02 -0.52
About Finn Peacock

I'm a Chartered Electrical Engineer, Solar and Energy Efficiency nut, dad, and the founder and CEO of I started SolarQuotes in 2009 and the SolarQuotes blog in 2013 with the belief that it’s more important to be truthful and objective than popular. My last "real job" was working for the CSIRO in their renewable energy division. Since 2009, I’ve helped over 700,000 Aussies get quotes for solar from installers I trust. Read my full bio.


  1. brandon williams says

    Golden Solar GS 50E has a Pmax of -.22

    • Gordon Norris says

      Hi Finn
      What would be the temperature coefficient of the Bosch Solar Panels, actually manufactured in Germany.
      I am looking at a 5Kw system to be installled in my WA Home on a North & North East facing roof. Using the Sunnyboy 5Kw inverter. Could you also add the Bosche Panels please?

      Many thanks & king rgds.


      • Finn Peacock says

        Hi Gordon the Bosch are excellent in the heat their temp coeffs vary from 0.33 to 0.46 depending on the model.

        If you split a system over 2 roof areas be sure to do this:

        • G’Day Finn
          Looking at A/C panels and system from Queensland Renewable Energy
          Do you know of the pros and cons of a/c compared to d/c .Would like to know
          your thoughts.
          Regards KURT

        • Hi Finn. Wondering your thoughts on current Simax panels? Im tossing up btw 4.5kw systems. Simax panels and sma inverter or tdg aps. Both about 8 grand. Am leaning towards Simax/sma system just unsure about quality of these panels.

          • Finn Peacock says

            Simax are Tier 3 panels according to the classifications I use – but… I know a number of good installers that really rate them and have been using them for years without problems. They tell me they get good backup from the manufacturer and great power output.

          • Hi Finn

            Just wondering what your thoughts were on Solarworld WA GY250P-60 solar panels? We are looking at a 1.5kw system??

          • Finn Peacock says

            Solarworld are very good, Tier 1 panels.

          • BarleySinger says

            I have the info on the SIMAX 250W for temp but it gives more than one Coefficient. I assume that “Pmax” is the Max Power Coefficient.

            Temperature Coefficients
            Nominal Operating Cell Temperature(NOCT) 45±2°C
            Temperature Coefficient of Pmax -0.39% / °C
            Temperature Coefficient of Voc -0.34% / °C
            Temperature Coefficient of Isc 0.036% / °C

            “Voc” = -0.39% (pretty close to what the example showed)

            HOWEVER… note that they measure “normal temp” at 25°C on most panels (which got plugged into that formula)…. but THIS panel is measured at 45±2°C.

            That ought to mean that they are a lot better in the heat. In fact at 42°C (±2°C) we ought to have full output.

      • Hello Gordon,
        Did you end up with the Bosch panels with the Sma 5kw ?
        If yes which model panels and are you willing to advise what the price was fully installed ?

        • I have just signed with a smaller company and I am getting the 5kW SMA inverter and the Stella Bosch panels.. I had 5 companies come around and found the smaller guy a lot better to deal with. His total price was a tad over 8000.

          Very good price I think? Have you had any prices Ross?

    • Marty Burgess says

      The way forward with this issue might be to see the excess heat as a resource and harvest it. The University of Wollongong and TAFE NSW Illawarra Institute have built a zero energy house in which the heat is harvested thereby optimising the efficiency of the panels. A pump moves the heat to under the house where “phase change material’ stores the heat until its required for other purposes (eg heating rooms during the night).

  2. Karl Jensen says

    Unfortunately thats only about 1/10 of the story when it comes to the right panel for the job.

    Sure temp co-efficients matter but if the thin film panels take up 3x the space then you can only fit 1/3 the panels.

    If you take the CEC advice you should oversize the array in respect to the panels by 20%. the example given uses 2.6KW panels for 2KW inverter.

    This accounts for temp derating in typical conditions and hence little or no energy is “lost” but the inverter can work in its “sweet spot” for efficiency.
    Unfortunately most systems even with the best components are poorly designed which has more of an impact than the panel temp co-efficients.

    A decent bird poo on a panel can knock down output as much as 20% from the whole array, hence we need some perspective here.

    • All solar panels have bypass diodes this means if one panel is partially shaded only that panels output is reduced not the whole arrays!

      • Finn Peacock says

        Hi Steve,

        Yes – most panels do have bypass diodes these days – but they only kick in at a certain shade threshold, and typically kill a third of the solar panel’s output in severe shade. Until the bypass diode kicks in the shaded panel will drag the whole array down with it.


        • Hi Finn

          I’m sorry, I must disagree with you. I refer you to the drawing of a solar panel with bypass diodes on the following web page. I have two arrays using mono and poly panels made by different manufacturers and this is how the bypass diodes are installed in my panels – except that instead of the 3 diodes shown my panels have 6 – each single diode has been replaced by two diodes in parallel. I guess the manufacturer had a surplus of 4A diodes and rather than purchase 8A diodes he used to 4A diodes in parallel.

          For the sake of argument (and to make the maths easy) lets consider a solar panel that has an output power of 200W – ie. a 50Volt/4Amp panel comprising of 54 cells in series (lets call this a string). These series cells are then further arranged into 3 sub strings of 18 cells each with each sub string including a bypass diode as per the above web page.

          At the panels maximum output each cell must be generating 0.93V @ 4A giving us a panel output of 50V @ 4A or each sub string is generating 16.7V @ 4A. If you were to shade one cell then that sub strings current and voltage will drop causing the bypass diode associated with that sub string to become forward biased allowing the current generated by the unshaded sub strings to flow through the bypass diode. The result is we now have a panel with an output of 33.3V @ 4A – the current of the unshaded cells, and therefore the entire panel does not drop. The panels output voltage on the other hand does drop.

          Now if we connect more of these panels into a series array and one panel is partially, or completely, shaded, provided all of the other panels are in full sun, the arrays current will not drop below 4A. What will happen is the arrays output voltage will drop. The bypass diodes do not limit the current they simply provide an alternate current path around a sub string that is not producing sufficient current/voltage to keep the associated bypass diode reverse biased.

          What happens if we made an 8 panel, 1.6 kW system out of these panels and totally shaded one panel? The maximum possible power loss of the array would be 200 W (the entire output of one panel) plus the power dissipated by the voltage drop across the 3 forward biased bypass diodes (due to the 4A of current from the other 7 panels flowing through them) – ie. 200 W + (0.6V x 3 x 4A) = 7.2 W (assuming silicon diodes each dropping 0.6 V) so total loss = 207.2 W.

          207.2 W out of a 1.6 kW array = loss of around 13%.

          Clearly this % will change depending on how many panels are in the array and would have to be calculated on a case-by-case basis.

          Given the way the panels are assembled you can lose 33%, 66% or 100% of a particular panels output and this is not dependent on the number of diodes.

          The point I’m trying to make is that because virtually all panels have bypass diodes completely, or partially, shading one panel cannot have any effect on the output of the other non-shaded panels.

          • Finn Peacock says

            Fair point – I wrote that reply too late at night and have corrected it! But bypass diodes are not the golden bullet to shading problems, because the panel can get pretty shaded before the diode kicks in, and drag the whole array down with it.

          • I would argue that the bypass diodes would ‘kick in’ pretty quickly, there only has to be a 0.6 V drop (for a silicon diode), even less is you use a Schottky diode, in the voltage generated by any one of the sub strings before the associated bypass diode is forward biased, yes there may be a small drop in the whole arrays output but only for a verrrry short time.

          • John Byers says

            Diodes in Parallel do not share current equally between them as they cannot be perfectly matched for equal forward resistance or turnover voltage. This means that one diode will pass more current than its paralleled mate (since its intrinsic forward resistance will be smaller) and may burn out if not adequately overrated. No matter if Ge,Si or Schottky diodes used this is basic physics. So two paralleled 4 amp rated diodes will not pass 4 amps each. One will pass more than the other and get hotter in consequence
            And getting exact match between pairs of diodes is an expensively time consuming and largely unrewarding exercise… even diodes off the same production batch are different to one another in this regard. Unless the paralleled diodes are both rated at 8 amp each the approach is unreliable

          • er….. this tech chit-chat is fascinating.
            I solved my shading problem with a small chainsaw: took the top 20 foot off the offending tree.
            ….don’t recall the relevant technical calculations.

  3. colleen morgan says

    Please let me know the temperature coefficient %/c

    of Suntech panel model STP190S-24/AD plus

    Thank you for your assistance

  4. how about conergy p 180

    • Hi Grace

      It is -0.44

      • Alright Geniuses of the Solar Tech talk, Please design the ultimate 5kw and 10kw systems for a house. It’s great to read how intellimagent you all are. Yet it would be more useful to us mere mortals if you advise us on ULTIMATE kits for home users in Australia. Thanks guys, Jake

  5. Marius Fourie says

    Everyone tells you that solar cells degrade at .45% per DegC above STC, but how do I predict the cell temperature?

    I know variables like wind direction, ventilation, etc.. makes it quite compilcated, but does anyone have practical figures? In SA (read Johannnesburg) we have about 5.6 hours sun with very little wind and summer temperatures of 28 to 32 DegC.

    Then, is it worth considering forced cooling under hot conditions?

  6. hi, could you please tell me the temp coefficient of ET m 660250 thanks

  7. Richard Salisbury says

    Marius, here’s a web page to go to for the calculations of panel temp

    And , if you are in the southern hemisphere, it is best for an array on a north facing roof, next best easterly facing and west if no other options – better still ground mount facing north or north-east

  8. Richard Salisbury says

    National Panasonic has a great product to reduce the effects of power mismatch caused to mono or poly panel arrays from shading, bird poo, leaves etc.

    It’s called a Solar Magic Power Optimiser

    With thin film panels these shading, dirt and debris problems are not a major factor – n by-pass diodes kicking in or kicking in at different rates

  9. Could you add Solon panels please.

    • Solon Black XT 295 -0.47
      Solon Black XT 290 -0.47
      Solon Blue XT 285 -0.45
      Solon Black XT 285 -0.47
      Solon Blue XT 280 -0.45
      Solon Black XT 280 -0.47
      Solon Blue XT 275 -0.45
      Solon Blue XT 270 -0.45
      Solon Black 245 -0.47
      Solon Black 240 -0.47
      Solon Corvus 240 -0.47
      Solon Blue 235 -0.45
      Solon Black 235 -0.47
      Solon Corvus 235 -0.47
      Solon Blue 230 -0.45
      Solon Black 230 -0.47
      Solon Corvus 230 -0.47
      Solon Blue 225 -0.45
      Solon Corvus 225 -0.47
      Solon Blue 220 -0.45

  10. Silly article! Implies that solar electricity will do worst in sunnier areas. Whilst there are losses due to the heat coefficient these are compensated by the extra sunlight in most cases. Have a look at the desert knowledge solar centre or sunny portal in high heat areas.

    • Finn Peacock says

      Hi Iain,

      Thanks for the comment. I certainly don’t mean to imply that solar will do worse in sunnier areas. What I am trying to say (perhaps clumsily!) is that if you have 2 places with the same amount of sunlight, the hotter place will always be worse for solar electricity than the colder place. The ideal place for solar power is a cold desert, or the top of a mountain. This is why the temperature performance of a solar panel is so important in Australia. And why the STC power of a solar panel is tested at an ambient temperature of about 5 degrees Centigrade.

  11. terry adams says

    Hi Finn

    Whatis the temperature coefficient of Simax. panels used by Sun Trix? Andy is coming to visit us. tomorrow morning at 11am.


    • Finn Peacock says

      Hi Terry,

      The Simax SM572-190 has a temperature coefficient of -0.39%/DegC according to the data sheet.



  12. how about sunearth panels

  13. Hi Finn, I live in Mareeba about 50 klms west of Cairns, we have very hot dry days durring summer and most days of 25c during winter. What sort of panels do you think I should be looking for? And what are your thoughts on one of my quotes on a 8.80kW system running through a SunnyBoy 5000TL of $17,990.00 with $7320.00 of rebate?

    • Finn Peacock says

      Hi Nigel,

      I think you should go for a brand name panel (Trina, Suntech, QCells, Solarworld etc), because you can generally believe their temperature specs. Look for a panel that is better than -0.5%/DegC. You don’t say what panels you are getting – but if they are good panels, then that seems a good price. I assume you will be running 2x Sunny Boy 5000TLs with 8.8kW of panels?

  14. I’ve been doing some temperature testing of panels, and have been recording temperatures that the panels get to averaging 50degC/day (sunlight hours) and some as high as 85degC. I guess using these numbers you can calculate the percentage loss of the system due to temperature increase.

    Why can’t someone make white solar cells???

    • Finn Peacock says

      Hi Angus,
      Thanks for the comment. Wow, that is hot! At 85DegC most panels will lose 30% of their power.

      Where are you in Australia, and what colour roof are the panels on?


    • Charlie b says

      Yeah they make white solar panels ( ON THE BACK ) the best colour there is BLACK (remember? blackbody radiation? – that same colour as on a fridge radiator?), so i think i will paint them (not sure if that effects warranty!). The reason why those blue ones do better could be because they reflect the blue light, rather than absorb it as heat (i do doubt they turn the blue light into energy as i think they are designed for IR)

      • Charlie b says

        I checked about the paint and it apparently doesn’t matter. White and black “Catalac” paint have almost the same emissivity (in fact, white was better). And, according to wikipedia, apart from colour (this must be a misconception), emissivity depends also how shiny the surface is (which may actually come down to surface area instead!). so i admit to being wrong in my last message. I will have to consider heatsinking and off-peak loading instead.

  15. Don Roberts says

    Could you give any details on performance of “Q” cell panels.

  16. Hi Finn

    Sorry I am totally new to this, i just got a new house and need to find the best one for our home we live in Brisbane and think which one is the best for us and about the Temperature Coefficient what dos it means it’s better -.2 better or .-.5 better?

    Thank you for your time^^

  17. Peter Jensen says

    Hi Finn, I have found your site very informative and to the point.I live in North Qld. I have 2 phase coming into my house and one quote is for 11.2kwET panels with 2×2.5 sma invertors for a price of around $22,000.The other quote is for 4.05kw hyundai panels with a sma invertor,$12,450. My average consumpton is about 26kw p day tarif11 and 8kw tarif 31. My question is, bearing in mind that technology moves forward quite fast, do I spend that amount of money or $12,000 so that if something super dupa comes on the market later I could spend the other $12000
    Regards Peter

  18. Vegelen says

    Could you add:
    Suntech STP250S-20/WD
    Temperature Coefficient of Pmax -0.45 %/°C

  19. Vegelen says

    Please could you add the Jinko range of solar panels to your list.

    Thank you for your help.

  20. Hi Finn
    I am getting a 5kw solar system with simax sm572-190w panels and JFY inverter / JSI -1500Tl. Can you please tel me It would work in northeast Vic .( good performance ) thanks

  21. Hi Finn
    My 5kw system has 26 190w panels that = 4.92w , can I put extra 2 panel to make 5kw. Thanks

  22. Hi Finn,
    I’m looking at buying a 3kw system using an SMA inverter and i have the option for 2 types of panels 1 that you have listed “Tianwei” and the other is “Senergy” not actually sure as yet of the model of the panels but do you know of the Senergy, and what in your opinion would be the better panel to go with ? I live in Brisbane.
    Regards John

  23. Hi Finn,
    I live in Melbourne and have received 3 quotes for a 5 kw solar package all coming in at around $11,000 all using SMA 5000 inverter but all using different panels, the panels are 1- LG 250S1C or 2- Canadian Solar CS6P 250P or 3- Solar Fun panels.
    Which panel would you recomend, the roof faces west and is pitched at 15 degress.
    Cheers David

  24. How about Lunio 190W panels?

  25. We live in yeppoon in qld and we are trying to work out what to do with solar. Our roof faces north east the panels will need to be split on two sides. Canadian solar cs6p 235px Illumilite is the name of the company we have been talking to any idea if they are ok. The salesmamn didnt seem to know anythig about the temp. Of the panels. Please help.

  26. Shaun McCabe says

    Another great article. I’d keep away from the comparisons with the UK though – given the climatic constraints, UK solar take up is reasonable, and overall renewables adoption leaves Aus for dead! For example, in 2011, 33% of Scottish electricity generation was from renewables, and this is despite copious local coal, oil and gas resources, and an established nuclear industry. Scotland is targeting producing 100% of its electrical needs from renewables by 2020.

  27. Hi Finn,

  28. Shahnaz Khan says

    Hi Finn,

    whats your thoughts on the Yingli Panda 270w mono panel? been quoted on them recently and they seem to be very popular in the US but still newish in the aussie market.

    • What do you think of the Yingli panda 260 W coupled with a Delta Inverter German design made in Thailnd.

      • Finn Peacock says

        Both good!

        • Leyland gale says

          Everyone is talking heat causing power loss. Fin what about the inverters being used.I done some research before choosing solar and I found that German Sma and omnik were good inverters and didn’t loose as much power when converting from Ac to Dc.the cheaper brand such as jfy were very average inverters.

          • Finn Peacock says

            Yes – the inverter’s efficiency is directly proportional to how much energy you will get. Also most of the cheap inverters (and some expensive ones) will start to derate at a not-too-high (for Australia) ambient temperature – so look out for that. And always mount them in a shaded spot. I see so many inverters in direct sunlight it is not funny!

            You can compare inverter efficieny here:


            Hope That Helps,


  29. Shahnaz Khan says

    Hi Finn,

    I also have a question about the lines in each cell which I believe they are called Buz bars? ive noticed most so called better quality panels usually have 3 and the cheaper ones have 2. is there a reason for this?

  30. I’m wondering about STS panels, particularly 250S-60. Brochure says 0.3

  31. I am looking to install a 5KW solar system in the next few weeks and have a dilema how to choose. All the quotes are similar, premium quality materials and workmanship. What your opinion between Simax SM660-250, ET-M660250 and Green Triplex PM250M00 panels and inverter SMA Sunny Boy, 5000 MTL Growatt and Delta 5000HF.

    • Finn Peacock says

      I have never heard of Green Triplex – so personally I’d avoid those.

      The best inverter is the SMA, then Delta, then Growatt. But all 3 are good inverters. I know some great installers that are very happy with ET and Simax panels.

  32. Thanks Finn for your quick reply. Yesterday I received my last quote that is based with the Schott SW 240 poly panels, German technology and made in the US, do you know this one.
    By the way thank you for this great site it help me understand the solar technology, I recomended to few of my friends. Continue on your good work

  33. Hi Finn
    I’m getting a choice of 2 panels the first is a Blue Sun 250 watt and the second is a Simax sm660 250 watt I have to make a choice very soon can you tell me which you think is the better panel. I live in Brisbane and they will be north facing the inverter will be a delta 2.5kw. Ive looked at both specs but can’t see much between the two


  34. anne gallagher says

    Hi Finn,
    One quote i have received has given me the choice of monsterland panels – made in Germany, (apparently) the other choice I have is Tianwei, who the installer seems to think is the better way to go???? I live in Mt Molloy FNQLD on the Nthn end of the Atherton Tablelands. Could you give me some advice as to which I should choose.

  35. paul jacobsen says

    very informative mate…. any opinion on samil power inverters 5KW

  36. Hi Finn,
    Thank you for the article which I found very helpful. I’m new to this and have been given a quote for a 5kw system using 20 BLD250-60M 250W panels and a JFY 5000TL inverter from my local electricity company. I couldn’t find much information about either of these and was wondering if you had any advice for me. Much appreciated, thanks, Jac

  37. Anthony penny says

    Do you know the actual output / operating characteristics of these Simax SM660-250 ? The manufacturer states excellent data figures for a relatively cheap panel or is it a case of to good to be true?

  38. Hi Finn,
    Thanks for the great article. Have you investigated the quasi-mono technology a lot yet? Renesola and some others like JA solar are already producing with the quasi-mono tech and it seems to have a much better temperature coefficient than mc-Si. In the 0.38-0.39 range. This is really important for guys like us because we can optimise a lot more yield out of our plants especially with very large modules as the land-efficiency ratio goes up. I am just searching now for their measurement methods to see how “real” these TC numbers are.

  39. Hello Finn, Your a busy fellow replying and people like myself thank you for your commitment to helping us through this minefield of choice. I live in Metro W.A and looking at getting a 4 to 5 kw system. It would have to be west facing. What would YOUR choice of panel and inverter be as i have had a response from your site of 5 installers . Can you also comment on (1) australian solar panels ASP-60-6M , and ASP-72-5M . (2) AS-5M …195w , and AS-6M30… 250w by amerisolar australia (3) Delta inverters , (4) YC 200 EU Micro inverter . Is it true that i could possabily lose up to 30% efficiency with west facing installation and more due to “Max Power Temperature Coefficient ” loss. A lot to consider. Thanks again , Frank.

    • Finn Peacock says

      You will never get more than 3 installers responding from – Are you sure you used my site – or was it a copycat? I don’t recommend “Australian Solar Panels” because I consider their marketing deceptive. The panels are made in China. Delta inverters are good.

  40. Hello Finn great site what is your opinion on a system using 5.00 KW TrinaHoney 20 X250 W Solar Panels with Samil 5200TL-D inverter in central victoria
    Any other recomendations

  41. HI Finn,

    Can you comment on Hosun panels in the Australian market?


    • Finn Peacock says

      I’m not familiar with those panels – sorry! They don’t appear to be approved in California, and I’ve never seen a review of them so I have no data with which to make a judgement!

  42. Hi Finn,

    I am looking for a system that is efficient in the Netherlands. In this search for the optimum, I encountered a question and could not find a credible answer yet.
    Is the monocristalline (eg. Canadian solar panel CS6P 240 (all black)) better than a polycristalline (eg. Canadian solar panel CS6P 240) or is it equal.
    My roof it headed to the west and the technician told me that polycristalline is not less efficient because (1) the cristals in the polycristalline panels are directed to all sides, and monocristalline get its energy mainly from the light that falls approx. perpendicular on the panel (2) the cells in the black monocristalline panels get warmer than the cells in the blue polycristalling panels, because obviously black surfaces absorb more ‘heat energy’.
    Theoretically the monocristalline panels should be better, but these effects are supposed to compensate the difference and in cloudy weather (with scattered light) polycristaline could be even superior I was told. Could you give your opinion on this?
    Rob, Netherlands.

  43. i have NESL (2KWH system) specs say normal operating temp is 48c+/-2c. ibelieve this means that there is no loss due to temp until the ambiant temp exceeds 28c then .48c for every degree over that’ so what is being said does not seem to be correct
    on the other hand i am told that i should not expect my system to ever reach 2kwh output . to date it has not 1.7kwh which i do not believe is satisfactory
    any comments

  44. Finn,

    Great thread,
    I live in Brisbane and I’m looking at a 5kw system with a 5kw PVI-5000-OUTD inverter and x24 Tianwei TWYxxxM660 250w monocrystaline panels with a temp Coeff Pmax of -0.47/ deg C. (apparently part of CSGC – global fortune 500 Co. ….. blah blah). I have 3 phase to the house and a 3 ph split aircon. What do you think of the system? I guess the extra 4 panels is to do with inofficiency reduction ? Quote $8.5k from Enviren

    • Forgot to mention,Inverter is made by Aurora with 10yr warranty and panels have a 10 yr warranty with average degredation over 23yrs of no more than 0.6%.

    • Finn Peacock says

      Enviren are good guys so your install should be good. I think that’s a good price. Power-one Aurora is a great inverter. The panels are budget panels, but one of the better ones from what I’ve heard. An upgrade to Trina Honey panels would perform slightly better in hot conditions.

      • I guess that’s why they supply 24 panels to reduce the inefficiency during hot conditions. I don’t that I can justify paying what some are asking for better panels …… some as much as $5k moreand only 20 panels so can’t see any room for effieciency loss when hot.

  45. hi finn

    which one is better honey trina or simax .


    • Finn Peacock says

      I’ve heard good things about Simax, but Trina is probably better; bigger company (Tier 1), better temp coefficient (so good for Aussie conditopns)

  46. What about Infi solar panels IN6P60 – 225 poly. (200-255w). What have you heard about these panels? Also the JFY-Tech Inverter jfy5000tl?

  47. John Watson says

    Hi, I am looking at installing a 5kw system. Been recommend to go with a Delta 5000HF Inverter and 20 x 250 Watt Mono panels made by Hanover from China

    Have you any opinion or knowledge about these items

    • Finn Peacock says

      Deltas are good. Never heard of the panels although I’m always wary of Chinese panels with pseudo German names!

      • John Watson says

        Ok, I wonder what other panels I should ask for. Have you any suggestions Finn.


        • Finn Peacock says

          Good budget panels include CSun, Renesola and Simax. Mid range panels include Trina and Canadian Solar, top end panels include QCells and Sunpower.

  48. To help overcome the problem of heat on solar panels I use a sprinkler with constant water flowing over the panels on very hot days this will increase my panel’s wattage from 260w to 360+w so I would assume on bigger arrays it’s increase would be considerable.

  49. I have seen Solar panels with a rear water jacket to keep the panels cooler and also provide hot water.
    Perhaps finned heatsinks need to be added, aluminium extrusions would be the best.

  50. Hello.

    About to install 5kw Aurora inverter and installer suggested these panels: STS 250-60 high efficiency Mono Solar Panels,new with QCells?,with 6 Bypass Diodes.
    Do you have any information on these panels ,manufacture etc



  51. Don’t know where else to post this. Just had a 5kw system installed, 22 x 250kw panels with tilt brackets on the roof and 5kw SMA inverter . 2 storey skillion roof and a difficult installation as power box no where near panels or inverter. Producing 4.6 kw in late afternoon. Installed by Ozzy Solar (Qld – Gold Coast) , Keith the sales guy very well informed and no preasure or BS, Russell install co-ord was easy to deal with and very accommodating, Damion and Corey install guys good work-manship and easy to deal with – really knew what they were doing and were able to include my wishes in the install and finish. Would recommend to anyone who wanted a well fitted system. Wasn’t the very cheapest system and by no means the most expansive but good equipment (panels and inverter) $1100 extra for tilt brackets and labour, total under $10k

  52. What is your opinion of Amerisolar AS-6M30-250w Panels? thanks

  53. ronald oxman says

    Hi finn, we live here in tasmania about four months ago we had 11 x 260 watt yingli panda panels put up on our roof and the results have been fantastic, on a sunny cold day here in july we are getting over 11 kw on the average

  54. Hi Thanks for the article sharing. I had been recommended for LG panels and SMA inverters for residential use in QLD. Now after reading, I’m slightly in doubt as to whether I should change to other panels. Has anyone used LG panels or have heard their pros and cons and in terms of comparison with bigger brand like REC, Trina etc? Any comments would be very much appreciated.

  55. Too bad bosch is now going out of business for solar panels and warranties will be a nightmare.

    • Finn Peacock says

      Bosch the parent are not going anywhere and should honor all warranties. But anyway a failed Bosch solar panel is rarer than rocking horse poo so you are highly unlikely to ever make a claim. 🙂

  56. Ive been quoted on some ZNshine panels from Electroy, Can you tell me their temp co. I have the measurements in kelvin

  57. Okay, so where is the combined Solar Power Solar water panels, taking care of both problems. Power side can run the pumps free and cool the panel in the process by circulating cooler water from the bottom of the tank. Use a heat pump water system and its all free.

  58. What about 235 watt Q-cells? Where do they rate?

    • Finn Peacock says

      They are generally awesome. Good performers in the heat and well built with German engineering behind them. One of the few “german engineered” solar panels that comes from a company that employs German engineers and has a German factory! (Although they also have a Malaysian factory making their panels too).

  59. Danny Cox says

    Hi Finn,thanks for your reports,can you advise on Tindo panels made at Mason Lakes in Adelaide,they claim they are the only ones made in Australia and are the best, see their web site for techno info you may be able to clarify.

    • Finn Peacock says

      Hi Danny,

      I know the Tindo guys personally. Yes: they are the only panels made in Australia. Are they the best? I don’t know – I need more data.

      I have 6kW of Tindo on my roof. They are built like tanks! And I love microinverters. They aren’t actually switched on yet as it is a new house and the second fix electrical isn’t complete yet. But as soon as they are up I will be placing the data/live monitoring live on my site.

      They are expensive. (20-30% premium), but they are fantastic quality from what I’ve seen so far.

      • Hi Finn
        Can you point me to some information on data/live monitoring please? – I am about to install a system (I live in Adelaide and am swinging towards Tindo).

  60. Had a 3KW Xantrex inverter with 1.9Kw of 10 x 190W A Grade Monocrystalline panels ( Solar Array ), then added another 6 x 195 Kw panels later on. Hembrows Electrical Service in S.e Queensland. Are the panels / Xantrex inverter any good ? They have cancelled my Bills into a small credit ( with the 1.9Kw panels they stopped my bills ($180-190 ) and got $240.00 credit over 3 bills. Was happy with install and they are doing what the salesman said. My 1st winter with lots of cloudy , rainy days ( $5 .00 credit / 3 mths and used my A/c as a heater , saving me about $135.00 in gas.

  61. You have put your decimal point in the wrong place to start with.
    You can play with figures but we have a 1.5 KW unit and we do not pay any electricity charges and we receive about $800 per year from feed in. .
    I cannot tell you how much carbon pollution is being saved by our unit, but they do not burn coal for us, so our footprint is clean.

  62. Hi Finn, is there scope for multi-storey unit dwellers (in a body corporate set-up), to have solar panels installed? If so, how complicated could the installation be, and what brand panels to use? I live in Cairns, Australia.

    Thankyou Finn,

  63. Finn,

    I am about to install SR-P660230 Sunrise 230W solar modules. What are thier Temperature Coefficient (%/°C)? A mate just forwarded me this page.


  64. Does anyone know of Adelaide based Solar companies / distributors that are stocking the Yingli Solar PANDA 60 Cell Series in 270w?

  65. Paul Margereson says

    How about BYD 240PG-30 panels please?

  66. Hi Finn
    Can you please advise your view of the Hanwha Solar SF 220 Poly x-tra. 2kw system. Combined with aurora 3kw inverter.
    Thanks for your great site.

    • Finn Peacock says

      Auroras are one of my fave inverters. I’m not familiar with those panels -although the manufacturer is very respected so they should be OK. Even better are Q-Cells panels – owned by Hanwha SolarOne.

  67. Bryan South says

    Could you add Csun Mono 190w panels please

  68. hi Finn,
    recently installed a 5Kw system with an Aurora 5Kw inverter and 20 x Hareon 250watt panels.
    We live in Bathurst NSW and at the moment experience winter temps and lots of overcast cloud cover.
    Results so far indicate an average daily production of approx. 15.3Kwh.
    I have not seen any comments on the Hareon panels but found the temp.coef. to be -0.44 which from your excellent chart would seem to be middle of the road.
    The system cost $6500 all up including new meter and instillation and was done by Dr Green
    from Sydney. When the weather improves (higher temps/longer daylight hours) will post again for comparison purposes.

  69. Jeremiah Alvarez says

    Hello Finn,

    Kindly advice still undecided whether to go for Simax or Trina. Price wise Simax not sure about panel quality. Trina panels is a sure bet. Any reviews on Simax from last 12 months.

    Please do advise.

    With deepest gratitude.

    • Finn Peacock says

      Trina are probably a slightly better panel – and a bit lower risk as they are Tier 1. Although there has been a lot of chatter about their finances (huge losses last year).

      But I’ve heard very good things about Simax from a number of installers I trust. And they have an Australian presence – so they should be a safe bet.

      If price was equal – I’d go Trina, but if Simax are a lot cheaper then I’d be tempted by Simax.

  70. Stephen Hunter says

    I think that even with the Temperature Coefficient it’s still better to have solar panels then not!

  71. Trevor Glossop says

    I live in western Australia so
    what if put shade cloth over my solar panels. would that help?

  72. You can easily do your own test in warm, sunny weather. I have SunPower panels, and on a hot day I got the garden hose and sprayed the panels – pretty slap-hazard. Anyway, I saw the production increase about 10% almost instantly. Some people are implementing their own spray cooling systems but using tap water might cause more issues with minerals buildup on the panels. Rain water would likely be much better. You need to work out the cost of spraying the water up there vs the benefit, though on the face of it, it looks worthwhile with rainwater.

  73. Geoff Martin says

    Finn – thanks for this useful info. The temp coefficient quoted by Tindo is -.3871. I have just contracted for 11kW on the roof. As you say, they are beautifully built.

  74. Hi,
    I’m considering solar from 2 different companies. One uses CSUN 250w panels and the other uses Tianwei 250w panels. There is a $2000 price difference between the two companies (Tianwei company is cheaper). Same amount of panels and same inverter. Can you tell me if one panel is better than the other? We live in Brisbane.

  75. Hi Finn,
    Thank you for your reply. The other ones we are considering are Sungrid High Performance Series panels. Are they as good as their name suggests? The salesman talked them up, as they do with the products they sell.
    Thank you,

  76. Neil Churches says

    What temperature did you use for the PMax data on your examples? My Suntech 190 Watt STP190S 24/Ad+ (11 panels) Temperature Coefficient is rated at 0.48 at a nominal operating cell temperature of 45 degrees +- 2 degrees?

    • Finn Peacock says

      I use a cell temperature of 50degC, which is an ambient temperature of 25degC. Remember the temp coeff is based on cell temperature. A black cell in the sun will be 25-45 degrees hotter than ambient.

  77. What about Renesolar poly panels, you have no mention of them?

  78. Neil Churches says

    I am interested to know what was the Nominal Operating Temperature (NOT) used for your Temperature Coefficient data? My Panel data sheets from my Solaheat installation say that its NOT is 45 degrees +_ 2 degrees rather than the 25 degrees your blog alludes to. My PMax data is detailed as 0.48 presumably for the 45 degree NOT.

  79. Hi Finn,
    Have you heard of muchen solar panels?

    • Finn Peacock says

      I’m not familiar with those panels. Be careful they are not pseudo-German named to make them sound European:

      My experience is that many pseudo-german panels are pretty shitty.

      • Funny, that.
        I;m old enough to remember when no sane person would ever buy cheap massed-produced junk for Japan.

        Now look!
        Ignore the brand-name ~ rely on the figures, and ~ more importantly ~ the warranty from someone who’ll be around for the longer term.

  80. Thanks Finn, I decided to purchase simax panels.

  81. I’ve had a quote for (all 4kw systems) Simax SP660-250 + a Growatt 4200MTL for $6,675 and one for Trina Solar TSM-235 PC05 solar panels and an Italian made Power One inverter for $7,644. I’m not sure if i should spend the extra bit and go with the Trina Panels with Power One inverter…
    I was also quoted for LG255S1K-G3 panels with a Power One Inverter for $7,861, but not sure about the LG panels…
    any recommendations would be greatly appreciated.

    • Finn Peacock says

      Power One inverters (aka Aurora) are great. They would be my first choice. But the Growatt will do the job – they are pretty good these days. All those panels are good (including LG). Trina would pip the post for me – all else being equal.

      • I got quoted for less by replacing the LG panels with REC panels, so i’m going with an Aurora Power One Inverter with 16 x REC 260PE Panels.
        Makes it hard when there’s so many options, your site is a great source of knowledge!

  82. Eric Coyle says

    I had a 4Kw system installed in Berwick Victoria and find it was a waste of money as we both work during the day so no one is home so we sell our solar produced electricity to the retailer at $0.08c per kW. While we are home and using electricity when it is dark and we are not producing we pay over $0.35 per kW. The sales men do not tell you this when selling there product.

    • Finn Peacock says


      A good salesperson will not quote you before understanding your electricity consumption patterns so that they can establish how much solar electricity you will export. Then they will size the system for maximum payback and give you accurate financial projections for you to make a decision from.

      Sadly, it looks like the salesman you went with did not do this. Can you let us know which company he was from?


      • Eric Coyle says

        They are one of the firms that have gone broke I am glad to say i now deal with a local firm in hallam for any maintenance that I need.

  83. Ann Mischlewski says

    We’ve been quoted by Electroy Solar for ZN Shine panels. I don’t see them mentioned anywhere in your list of panels. do you know anything about them? We are in Qld

    • Finn Peacock says

      I would class ZNSHine as a Tier 3 manufacturer. But… the actual panels are pretty good from what I’ve heard.

  84. If you want to double your output of your solar panels on hot or any day run water over them, quite often the power used by the pump to cycle the water is much less than the gain..

    • Hi John,

      I done this but would seriously not recommend it.

      I have 12 x 190 Suntech panels and a Sunny boy 3kw Inverter. I ran garden irrigation pipework round it and connected to a timer to come on every 20 minutes for 5 minutes.

      The performance during the water on time and after the panels cooled was phenomenal. Unfortunately during the water off time the water on the panels evaporated and the performance soon went down as the heat built.

      So i put the water on time on for longer and eventually had it on for 25 minutes then off for 5 for 7 hours a day and was using near-industrial amounts of water which i was collecting and pumping into my veggie garden. I’m a control system engineer so had a PLC controlling everything. It was beautiful. It took so much water I was killing my veggies so I cut a hole in the fence and piped it to the neighbours garden to water his garden too in return for watermelons etc.

      Additionally, when the residual water on the panels evaporated it left a calcification on the panels which degraded the performance to such an extent that I stopped and had to use a caustic solution to get rid of it. I removed the system after this the performance was so bad without using cooling. I don’t know if the panels have really recovered as it was murder to get rid of all the calcium (limescale).

      As I said amazing performance and I would run water over it if continously if I had my own source of demineralised water but beware.

  85. I find it hard to believe that the number one selling panel in Australia being the TRINA 250W Honey module with a 0.41% temp de rating is not even on this list!?


    And does anyone know if the Sanyo’s are even available in Australia and their relative cost to other panels?

    Why is a 68W panel number one on this list? This list makes no sense at all and is completely misleading in the extreme!!

    • Finn Peacock says

      Hi Jason,

      If you check the date – you’ll see the post was written January 21, 2011.

      Sanyos are available, they were bought out by Panasonic and are sold under that brand.



  86. I farm in WA’s Midwest,its hot dry and near the coast (Dongara) ,though only 35 km from town , no power ! You refer to government subsidies ? Joke …they work for city folk who do not need them .My experience ,with subsidies is ,I engaged several known firms to quote . I was getting excited about the fuel savings etc.Shock ,horror best quote $70,000 for 3 bedroom small farm house .Government subsidy was $35,000, I pay $35,000. I received good advice from the government solar subsidy office ,suggesting $12,000 was a more honest quote.I found an honest young tech guy who helped me e-bay buy and install a combination of solar panels and an excellent wind turbine to provide 24 hour power luxury, cold water,a fridge,freezer etc.Because my helper is not registered no subsidy for me .But I still feel ok , at $4,500 total cost , I saved the taxpayer y myself $65,000.

    This type of discussion board is a huge help to me ….thanks

    • Ray brown says f who gave you a hand with your solar set up regards ray brown I live on neaves rd out of wanneroo

  87. Hi
    Could you throw some light on the Yingli solar panels 250 w,just signed up for them yesterday.


  88. John Tapscott says

    Does anyone know why existing energy companies are not offering their customers solar electricity paid for as part of their regular energy bill? It seems to me this would make excellent sense.

    • Finn Peacock says


      Off the top of my head, Ingenero ( ) and Sungevity ( ) offer leasing schemes which are very close to what you are looking for.

      Hope That Helps,


  89. Ernest LEWIS says

    What’s your opinion of BlueLine XT 195W Photovoltaic Modules and BlueLine M15000 Single Phase Inverters?

    • Finn Peacock says

      From what I have heard they are overpriced and their performance is massively exaggerated by some of the people selling them.

  90. Hi,

    Just wondering if you could tell me how effective they are in Darwin?

  91. Ian Silvester says

    Hello Finn
    Could you give an opinion on Hanover Mono please, I assume they would be made in China, just had these suggested to me by a sparkie.

  92. truthsayers1 says

    Great post and lots of great responses. I have to admit I havent read them all.

    We have solar we have a 5kW SunPower Panels and a top West German Inverter. We are happy with the 18.5% return on capital spent to install..

    Now the question. If you buy a panel best suited to Australia high roof top heats lets say (its optimum) 38 degrees. On a colder yet sunny day does its high temperature efficiency rating work in reverse against you if its roof top temp has not got up to its optimum op temp..?


    • Finn Peacock says

      No – the temperature coefficient will not work against you if it gets colder. Panels can;t be optimised to work at their best at an ambient temperature of 38 degC, they will always work better if it is colder than that. A good temperature coefficient just means that their power output degrades less as the panel temperature goes over 25 degrees C.

      And remember for a panel temperature of 25degC, the ambient temperature only has to be about 10 degC.

  93. Roy -Geelong says

    All this temperature co-efficiebt stuff might give guidance to the best performing panel on a hot day but that doesnt mean the same panel will produce the most electricity over its expected life. A similar survey of the expected power drops over 5, 10, 15 and 20 yrs needs to be added into the calculations. A panel with a co-efficient of 0.2 may not be worth putting in if it only lasts half the no. of yrs as other panels.

  94. Ernest Lewis says

    Hi Finn, thanks for your reply altho it has left me apprehensive as I have bought a 5kw system. If the system doesn’t come upto its published literature, isn’t that false advertising? They quote Nom. Operating Cell Temp as 47+/- 3C. would that be with an ambient of 25c?

  95. Robert Harris says

    I have had my solar panels on my roof for about 3 years now. When they were first placed on the home I had ongoing fights with the then ETSA and Origin Energy from who I purchased the system from that the numbers that I was given at the time of purchase did not add up to my power bill. This was ongoing for over 12 months and got me nowhere as the deal was done over the phone. I asked to hear the recorded conversation of the deal but was told that they did not record what the sales man said only what I said when I agreed to buy the system. Even today it still does not add up to the BS I was given and have to put up with what I now have. Crap system with crap service from the power supplier and ETSA who supplied the import export meter with a hefty price that I do not own.

  96. Hi Finn

    Thanks for your very interesting article. We are building in Brisbane and want to instal solar power as we were happy with it on our previous house. The electrician says they instal a brand called Solarland Australia. Can you give me any advice about this brand? Their quotes installed are:

    3kW Solar system – $6,314 incl GST, minus current STC value of $1,798 = $4,516 (your out of pocket expense)

    5kW Solar system – $9,406 incl GST, minus current STC value of $2,958 = $6,448 (your out of pocket expense)

    Ross McColm

  97. we have a heat bank hot water systemtht attracted the solar rebate so we got it for $200 at the time just wondering on yr opinion o whether they r worth buying if ya gotta pay full price .i was told they use %75 less power than a standard elc hot water system

  98. chris rourke says

    Hi, what about using the material they use in self-varying spectacle lenses? would this be any help in the heat/efficiency drama? chris

  99. Jack Wilkins says

    Hi Finn, I have just bought a home on the NSW central coast.
    The company that installed them on the 21/9/2010 are no longer in business, they used Ningbo Sola – Sun-Earth TDB125X solar panels with an Orion High Efficiency Grid Feed Inverter, model number SPG-360-2KO.
    What’s your opinion on this system??

    I have also been told the panels are German and are positive earth.
    What does positive earth mean and is it good or bad.

    I am entitled to the 20 cent rebate till 2016, so this will be good.

    A friend has just installed 19 panels from a company who is an agent for Diamond Energy in Victoria, they are giving him 25 cents feed in price, what’s your thoughts on this.

    • Finn Peacock says

      Hi Jack,

      1) Make sure the panels really are German. Sun-Earth panels are good – but they are not made in Germany.

      2) I would go for a more mainstram inverter brand personally:

      3) Positive earth simply means that the positive wire on the panels is connected to earth. Most panels are negative earthed. But it does not affect their performance. Sunpower panels are positive earth and they are one of the best panels money can buy.

      4) The 25c FiT is a legitimate offer. They are happy to pay a few hundred dollars to get you as a electricity

      Hope That Helps,

      Finncustomer because the costs of acquiring a customer are very high (about $300+) in the electricity retailing industry.

      • Bruce Simmons 351 Firetower Rd Koonya Tasmania 7187 says

        Hi Finn. I also have Sun Earth Mono Crystalline Panels 250w TDB125x125-96-P and a Fronius IG 70 Inverter by Beacon Solar. I was told that it was all German made and also what is the Coefficient of this unit.

        • Finn Peacock says

          Sun Earth are good panels but are made in China. I would ask Beacon why they think theirs are made in Germany. Misleading people on the origin of goods is very serious, and the ACCC recently fined EuroSolar about $150,000 for implying their panels were made in Australia.

          Fronius are an Austrian company. I’m fairly sure the inverters are still made there. They are very good too.

  100. Had an Aurora aka Power One inverter fail within warranty and replaced FOC. Problem – found no qualified sparkie prepared undertake work and bill vendor for his services. Evidently with good reason!
    I paid up front & six months on have not been re-imbursed for costs incurred within Powerone’s guidlines. Subsequently unable reach parties I had dealt with – calls ‘shielded’ & emails remain unanswered. Hopefully the equipment generating on average 22 units : 7-8 usage holds up and I do no have to contact this supplier again. Caveat emptor!

  101. What about Kaneka Thin-film Silicon PV (PV (a-Si) sold by Solarshop?

  102. Merry Christmas & Happy New Year !

    Would appreciate your advice on Tindo solar system suitable for a retiree’s own house in Balwyn, vic 3104. To minimise panel heat up at 25 C+ ambience what cost effective pre- installation set up is required? How much would it cost?

    Thanks, Flynn,


  103. Larry Carter says

    The panels we had installed are supposed to be Munchen Solar. You might be able to find them & add them to your list.

  104. Geoff Sherrington says

    Has anyone done the sums now that there are a few panels installed in Australia and worked out how much fossil fuel use has been saved by going solar?

  105. Hildergarde Hammhocker says

    There is a lot of MIS information this guy is twerking on about. Solar panel ratings are published at an output specified as the “testing” temperature in order to rate all of them to compare. The co efficient quoted here does not necessarily relate to the particular panels efficiency when compared to another brand. Obviously this is a commercial con job.

  106. Solar Tipping Point says

    What about Kyocera that have 40kW+ systems running for over 30 years with less than 10% deterioration. Most of the panels mentioned are new market entrants and you’re going off datasheets, not real world performance

  107. drsmyth2013Louise says

    My supplier explained the performance loss on hot days when I purchased. Guess what? My summer bills used to be around 50% of the winter bill.
    The winter bill is now around 50% of what it was even after 8 years.
    And the summer bill? It’s about 10-20% of the current winter bill.
    Only 3 plausible explanations:
    1. I’ve changed my usage pattern – No.
    2. There is something funny about the way SECWA charges – Quite possibly, but I don’t think that is the explanation for this, based on my non-solar friends & my own bill breakdown.
    3. The theory is sound but, in practice, it has no appreciable effect…..

  108. Finn
    Can you give opinion on LG panels

  109. John Crocombe says

    I’m still not convinced that the power produced by solar panels (as we know them) during their lifetime, equals, let alone exceeds, the power consumed during their production. I’ve heard that using aluminium frames contributes to a large part of the power usage during production, so to help them actually save the planet, we need to find a “cheaper” way to hold them together. If panels actually generate more power than they use to make, why aren’t all the Chinese factories covered in them, rather than relying on burning our coal in thermal powerstations?

  110. Brisbane. I have 14x250w panels into a 4.5kw inverter. Panels are mounted flat due to my flat kliplock roof. In summer I am generating 1kw at 6am while my neighbour who has 30 degree mounting facing due north doesn’t generate this until 9am because the sun rises here south of east. Also I generate more when cloudy because flatter panels see more sky area. Moral is don’t mount panels at steep angles in northern Aussie latitudes.

    • John Crocombe says

      The recommended panel angle, for best overall performance, is supposed to be equivalent to your latitude, which is about 27 degrees. If the neighbours inverter and panels at 30 degrees are of a similar rating to yours, they should be producing a fair bit more than yours from Autumn through to Spring and end up producing more kWh for the full year.

  111. Janet Redbond says

    I am reading a lot of technical stuff and while I am not desputing any of it – all I know is I decided to get solar panels put on over 12 months ago. I am not really sure what type they are – but I am REALLY pleased with them. My power bill has reduced by about 3/4. Mine was set up by True Solar – the guys were brilliant and I am very happy. !!!!

  112. dennis Chamulke says

    I live in Alberta Canada and work on various solar systems we get on average 6to 8hours of light during our 6months of winter. from Dec to march we can expect -30 to -40 ambient temperatures what I am wondering about is . What does extreme cold do to the outputs of solar panels?
    Dennis C

  113. Trish Bourke says

    It is great to read about the efficiency of solar panels under differing climate conditions. Would hosing panels to cool and clean on hotter days in Melbourne help keep the panels working to their maximum capacity?

  114. Jon Kendall says

    I want to be environmentally friendly but have heard that the total energy cost of mining raw materials + manufacture and distribution is actually more than the total energy produced by solar cells over their lifetime even if they are not damaged by hail or compromised by bird poo. Is this true?

  115. Dennis Chamulke says

    My comment is still the same. Does anyone know how – 30 degree or -40degree temps affect solaor panels?

  116. Finn Peacock says

    Hareon are a Tier 1 panel manufacturer. I initially thought they did not have an Aussie office – but after a prod from their Aussie office – I now know that they do have an Australian Office!

    By all accounts they are pretty good. They are in the comparison chart here:

    and they are on this list:

    • Mark Group were a no show, they cancelled and I have to make another app with them.
      Soltek were really good, they gave me two quotes, one with 20 Simax 250 W Poly Panels and the Growat 5000 MTL 3 Phase Inverter, this was their sought of budget quote at $6,900. There “better” quality quote was the Hareon Tier1 255 W Panel with SMA Tri Power Inverter for $7,700.
      Never heard from Solaray.
      Horizon called out of the blue, I must be on some mailing list now. They matched the Soltek quote but using the 4BB panel saying it was better ?
      The third quote I got from a smaller local which was way too high in comparison.
      So at this point I am now just

    • If I went with the Hareon panel which one is better?
      3BB HR-245-18/Cb — HR- 265 -18/Cb
      4BB HR- 240P – 18/Bbf-1 — HR- 260P-18/Bbf-1

  117. Please help. We have had a quote from Solar World WA for 16 panels with a total output of 4kW. The overall price including micro inverters was $21900, but has been reduced to $17750 after rebates. This seems excessive considering the costs everyone else has mentioned. Are we being ripped off?
    The micro inverters are APS YC500/YC250 and the panels are GY250P-60.
    The salesman spoke of these panels being tier 1 panels as opposed to lesser performing tier 2 or 3 panels. We signed the contract today but have a 10 day cooling off period

  118. please help, I have two quote for 5KW. 22×250 Renesola panels and SMA Sunny Boy 5000TL @$8000
    24XGY250 Panels and JFY Suntwin 5000TL @$5000.
    Please give your advice

    • Finn Peacock says

      I’ve never heard of GY Solar. JFY Inverters are probably the cheapest inverters on the market. And, well, you get what you pay for in my experience.

      Renesola and SMA is a good combination(Tier 1 manufacturers). And it is a good price -if well installed.

      • Thanks Finn, I will go with SMA and Renesola. They are not a big player in WA, but small local company (very close to my place) and happy to give 10 years workmanship warranty. Before I give them a green light, do I need look at any-other thing.

  119. Hi Finn, your site is great and I very much appreciate the knowledge I have gained. I will recommend it to my friends.

    I have two quotes for a 5 kW system –
    Electroy a local Brisbane company who will use Yingli 250 watt panels – $7100
    and Solar Freedom (a national company using local contractors) who have quoted $5850 using Trina Honey Panels. Both companies have recommended an Aurora inverter….

    Electroy have said they will arrange for my electrical hot water system to go to a daytime tariff and be powered from the solar panels.

    Which Panels ?
    Which company?
    Hot water change over?

    Thanks so much for your help……

    • Finn Peacock says

      Yingli and Trina are both good Tier 1 panels. Yingli is the biggest panel manufacturer in the world. There are quite a few ‘grey imported’ Trina panels around at the moment – so just check that the ones you are offered are official Australian imports.

      I’m not familiar with Solar Freedom, so can’t advise on them. Electroy I know and I can recommend them (disclosure: they are a client).

      Yes – if you can arrange your hotwater to only be powered by any *excess* PV, that may be more valuable than exporting it at 6-8c per kWh. But you need a pretty smart sparky to do this properly.

    • Very dubious regarding changing controlled hot water to solar!

      Regarding electric hot water, you should ONLY change hot water from controlled to solar power if your total refund rate you get for the solar power you export is LESS than the tariff rate for the controlled hot water.

      Even so, if you connect your hot water to the normal circuit so it gets some solar power, you will then be charged at a much higher rate whenever the solar system is not generating enough to power the hot water heater plus anything else you have running. (eg. when cloudy)

      In summer when you run air conditioning, because of clouds and/or hot panels, having the hot water on top of this will push you demand over what the solar panels can produce so you will be paying a much higher rate for your hot water.
      You’ll be very lucky to generate 2kw on a cloudy summer day in Brisbane.

      If you must change it, install a timer so it only heats between 9am and 3pm (with an override when you expect smelly visitors from Melbourne!)

      Depending on how much hot water you use, your solar power generation pattern over the day and your refunds, I think you will find it is still overall cheaper to keep on controlled supply.
      I’d be keeping a weekly log of controlled water meter, solar generation, exported and imported for 3 months or so to see before I changed.

      Only if you are an experienced DIY and your refund tariff is LESS than controlled water tariff you could put a current sensing relay (coil) in the solar supply AC that only closes contacts for hot water when the panels are supplying current. This would ensure the hot water always ran on the solar.


    • Some info that might be of interest and a few questions

      Does anybody know about STS 260w panels? (China)

      Performance report:
      I have had 14x260watt panels (3.6kw) installed since July2013. Connected in 2 parallel strings of 7 to a 5kw JFY inverter.
      In that time they produced nearly 4mwh, I imported 2.4mwh regular & 850kwh controlled and exported 2.6mwh
      I have a total credit for around $300 so far because I just got in at the 50c export rate the day before it closed so I can’t complain.

      Is this a fault?
      One panel had developed 5 pale greyish “smudges” under the glass about 2cm wide in a few spots (I’d attached a photo if I knew how to!).
      The power produced at midday (May) under bright sun seems about 20% less than it did last August so I am wondering if the panel is faulty. (Measured after cleaning)
      I wonder what happens in this case. Does the good string effectively blank off the string with a dead panel from realising its full capability like paralleling a good and bad battery or does it automatically adjust?

      Is it OK to cover each panel with a sheet of cardboard in turn to see if the slight reduction in power is the same for each panel or will this create any damage? The panels are supposed to have 6 reverse diodes each but if these are faulty then the whole reverse volts would be across the panel I blanked out.

      I also notice that in the afternoon when the trees to the west shade half of each string, the output drops to 500watts even though 8 of the panels are still in bright sun. I would have thought that I should get twice that.
      Is this normal or is it because the inverter is incapable of capturing at lower levels?

      Hidden benefits.
      My panels mounted flat, straddle the center of a slightly domed metal kliplock insulated roof. The shade of the panels has made the house noticeably cooler to the point where we have only run the 3kw air conditioning on the very hottest of days. As the whole house concrete floor doesn’t heat up so much, it ends up cooler at night not needing air conditioning at all like previous years.
      Previously when we entered the shut up house at a hot midday, the wife rushed for the airconditioning knob but now we find it cooler than outside! I guess we have saved hundreds $ from this effect.

      • Finn Peacock says

        Hi Ted.

        I’m not sure what that is. There is a thing called PID that creates whitish patches, but it is usually accompanied by black lines.

        But it certainly is a sign of premature degradation in my opinion, and any solar company who cares about their products should be taking it off for inspection/testing at their expense.

        The cardboard test would not do any harm, but would not tell you anything useful. You really need a sparky to test it with the proper gear. Some tests can be done on the roof, but I’d recommend putting it on a proper flash tester to see exactly how much power it is losing. If it is losing power – it will be dragging your whole array down with it.

        Hope That Helps,


        • Thanks.
          Hopefully you got the photos of STS panel blemishes (from my other email address)?

          I may have a sort of stalemate with the company.
          The system is still under full warranty
          Initially before they agreed to looked at the panels, they wanted me to sign an agreement that I will pay a $100 + hourly charge call out if they find nothing wrong with the system and want my credit card details!

          I have sent them the photos and not had a reply yet and I am going to have another go at them!

          Do you think placing a sheet of cardboard over each panel in turn and noting the drop would indicate if one was faulty? The faulty ones would give the least drop.


      • Finn Peacock says

        Here’s what a friend who has expertise in faulty solar panels says about your panel Ted:

        “Without inspecting the modules I can think of two possible causes:
        1. Some sort of residue left from the manufacture of the panel (eg solder flux residue). In this case it could be an early sign of delamination.
        2. A corrosion issue similar to that seen with “snail trails”.

        In both cases I would expect minor reflection losses and if there is corrosion some small Rs loss as well. However, if the panels were IV tested they would almost certainly fall within their warranted power. EL testing would confirm the extent of the issue, but this is probably not warranted.

        If it was my system, I would either get the panels replaced at the manufacturers expense, or install Solar Analytics to monitor my system and determine there is any power loss. If the panels were not replaced I would also get the manufacturer to write me a letter stating that these panels remain under warranty, and that if there is any further increase in visual or power loss degradation that they will replace the affected panels at their cost.”

        [note: Ted has just emailed me to let me know that his solar company has replaced his panel for him. Good on them!]

  120. Arjay Gementiza says

    Hi Finn,

    Would like to ask which is better string inverter (SMA) or microinverter (APS)? And for mono panels, Renosola or Simax? Thanks

    • Finn Peacock says

      I’d go SMA, as I would rate them as more reliable than APS microinverters.

      I’ve heard good things about Simax, but price being equal, I’d probably go for Renesola, as they are widely accepted as a Tier 1 manufacturer.

  121. hi finn looking at getting a 3kw system using sma inverter and either et or lg solar panels what would u recommend as I live Adelaide thanks

    • Finn Peacock says

      SMA is an excellent low-risk choice for the inverter. Both ET and LG panels are good. I’m hearing a lot of good things about the performance amd build quality of LG at the moment, so I’d be tempted to go with them.

      • I think SMA and LG is best option. I installed 5kw system (SMA- 5kw inverter and 22 250w LG panels) at my house(WA Canning Vale) 2months ago.It is producing 30kw/day on good sunny day(August). Even with lot of rainy days in July, It has produce average 20kw/day in July. It is beyond my expectation. I am really happy about product, appearance and quality.

      • thanks finn theres a ruffly 1200 dollars diff between the two but the lg panels ur getting 3.3kw instead of 3kw with the et panels

  122. hi Finn looking at some different quotes on a 3kw benq 14×260 panels with delta inv,or ja solar 14×255 panels with delta inv, jinko 12×250 panels with a delta inv, 12x daqo250 and fronius inv
    living in WA the benq is $500 dearer (than the other 3 quotes of $3900)
    would the extra 2 panels make up for any loss in performance or efficiency.
    or jump $1000 and have canadian solar panels and jfy inv

    • Finn Admin says

      Hi Brett,

      They are all good panels. I’m not a fan of JFY inverters personally (many installers disagree with me on that one though!).

      I’d be very happy with JA or Jinko panels. They are good, bankable, Tier 1 manufacturers. If price is equal then the extra 2 JA panels will certainly boost your system output. Deltas are good inverters. Built like tanks!

      Hope That Helps,


  123. Hello my friend

    I’m installing emphase inverters

    Should I go the Simax sp660 route
    Or the trina route

    Apparently simax has a coefficient of 0.39


    • Finn Peacock says

      I’ve heard great things about Simax panels – but personally, I’d go for the peace of mind of a Tier 1 manufacturer like Trina.

  124. Just bought a house in WA and looking to install solar power. Currently looking at 5kW systems but don’t know much about what products to go for! Wanting to know whether to go for Growatt 5000 MTL-S Dual MPPT with either ReneSola 250W Virtus2 JC250M-24/BBV-2 or iSolar ISP6-250/60 panels. Or go for the Fronius Primo 5.0-1 inverter? There is a big price diiference between the two, and it is considerably more expensive for the ReneSola panels over the iSolar. I’ve been told the Growatt is just not reliable at all, but don’t know if this is just a marketing ploy to get me to upgrade!


    • Finn Peacock says

      The Growatt will do the job and is well supported in Australia (so warranty should not be an issue), but the Fronius is better (more reliable). Further the Fronius is more likely to be compatible with a battery system in the future. Hence the price difference!

      I’ve never heard of iSolar, so I would avoid them. Renesola are a good Tier 1 panel.

      Make sure you get more than 1 quote though.

  125. Tracey Collison says

    Hi Finn
    Just wondering if you have heard of a company called Empyreal from Qld? They use Q cells and Sunnyboy inverters.

  126. John Price says

    I got a 5.13kw oversized system in Sydney comprising 19 x 270watt Yingli Panda panels and a Fronius Inverter.

    The first few weeks in September the power at its peak was around 4.8-4.9kw. On one particular day the inverter noted that 5,074 watts was coming down the system for a period of about 30 minutes. The peak days were sunny days around 23-27 degrees.

    Since that peak day we have had only power on warm sunny very bright days of around 3.8kw (maximum) with temperatures hovering around 30 degrees and little breeze and completely cloudless skies.

    I understand there is some loss of power when the temperature rises or some cloud cover.

    My concern is that maybe one panel has gone out either through a fault or a possum or something. The consistency of not going above 3.8kw all sunny week has me concerned after the previous higher peak readings.

    The 19 panels are 7 facing north and 12 facing west/north west.

    What could explain the much lower peak power reading in comparison to previous weeks?


    • Finn Peacock says

      HI John,

      They are great panels and one of the best inverters – so unlikely to be a hardware issue.

      The most likely thing is a bird poo – or other soiling of one panel – this can affect the whole array for the reasons shown in the first 30 secs of this video:

      If you can safely inspect them – check for this. Cleaning the affected panel should fix it.

      If the panels have no obvious soiling then it is probably time to get the installer to do a system check on-site.

      Hope That Helps,


  127. Im thinking of using select conect offering 3 1/2 kw 14 panel (gyn co) $5590 sma inverter covers all out of pocket expences 25 yr warenty aficency 10 yr warenty workmenship 5yr warenty ? +5 or 10 yr warenty inverter is there anything else i need to be asking whats the story of hail damaging the panels regards georgia

  128. Hi,

    I want to install a 5KW system in melbourne with a microinverter, which panel would be a the best way to go.

    is APS better than Canadian Solar

    • Finn Peacock says

      Hello Kush!

      Canadian Solar is a solar panel brand. They are good, tier 1 panels.

      APS is a budget micro inverter brand. I personally would recommend Enphase micro inverters as I believe they will be more reliable. They can go on almost any 250-260W panel.

      Hope That Helps,


  129. Mike Huggett says

    Hi. Can you tell me the reliability of BP Solar BP2150S panels? I have an opportunity to buy 11 of these which are probably at least 10 years old as BP stopped manufacturing somewhere then. I have 6 * 24V SX150S by BP already installed since 2003. I replaced one after 4 years as U/S. Not sure how well the others do as I get about 10 amps out of 3 parallel strings of 2 panels in series as my system is a 48V system and these panels are 24volt. It is very hot now around 35C ambient. They sit on a tin roof offset by about 100mm from the tin. God knows what the cell temps get too. Possibly a panel may be faulty. Difficult to check. Wanted to use these extra panels to replace 16 * 80 W 12V Solarex panels as they are not producing well and at least 3 panels are faulty. Been installed since 1998. I plan to get a new system when my 850ah Century Enersun batteries go home. Maybe another couple of years as I have tried to look after them. If you know a good way to test the life left in a Solar battery please let me know.
    Many thanks

  130. What’s the numbers for REC 280W twin peak panels and thoughts on solahart as a provider/ installer. Looking at 21 x 280W REC twin peak solar panels and a SMA sunnyboy 5kW dual input battery upgrade capable system? Also would you choose canadian solar, et solar, trina or rec panels whats your preferences

    • Ronald Brakels says

      Hello Sussy. Twin peak panels have a 10 year product warranty and their two halves function independently of each other so if half the panel is shaded or has bird poop on it the output of the other half won’t be affected. This makes them more suitable for installations where they will suffer from partial shade. (No panel performs well in complete shade.) But if your panels will be free of shade, this feature is less useful.

      SMA inverters are among the best on the market and should operate without problem for many years.

      Canadian Solar, ET Solar Trina, and REC panels are all fairly comparable and it is difficult to say that one is clearly better than the others. They are all tier one panels with 10 year product warranties and should last for decades.

  131. Indranil Palit says

    HI finn,
    Could solar panels work on martian environment with a maximum temperature of 20degC at the equator? I wanted to quote a full literature review on this topic in our college, but I am stuck with the numerical analysis. Wanted your help

  132. Murray Hacker says

    Do you know of anyone having dealings with Sunboost in the way they do business and their tier 1 panels etc. They have an aggressive ‘sell’ policy, but I well know my rights as a consumer in this country. They are using tier 1, 330w Astronergy panels Can’t remember the inverter, but will look it up. Cheers Murray Barmera SA

  133. Heizen Black says

    Great article! By their nature, solar systems need to tolerate high temperatures. I position them in a location to capture more sunlight, which makes them exposed to an ample amount of heat. But, how hot do solar panels get?

    • Ronald Brakels says

      This article suggests they will typically be around 25 degrees hotter than air temperature. But the article is quite old and now, when the sun’s shining on them, panels are usually around 20 degrees hotter. They don’t get quite so hot mainly due to improved panel efficiency.

  134. Peter Sketchley says


    I was wondering if you could help me..
    I’m looking for larger wattage panels 400-700watt..
    BUT, I need them to have a terrible thermal co-efficiency..
    OR… I can construct my own panels with suitably terribly poor temperature co-efficient solar cells…

    I’m setting up an experiment that will require the panels powering it to be inside the experiments internal environment…

    It will be 10-20 degrees Celsius below.. perhaps even lower later on if all goes well..

    Therefore I’m looking for the worst temperature co-efficient cells/panels so they will be the most efficient at such low temperatures…

    The problem I’m having the most is that while terrible temperature co-efficient cells and panels are available, they seem to already have a poor efficiency of 14-15% at 20-25 degrees Celsius to begin with… so cooling them down only means they’ll catch up with the more prominent cells-panels that have a higher starting efficiency of 20-23%….

    Any suggestions?
    Do you know of solar cells/panels with an initial efficiency of >20% with a terrible temperature co-efficiency?


  1. Website says:


    The truth about Solar Panel performance and temperature | Solar Power Blog…

  2. Tassie comes in from the cold | Solar Power Blog says:

    […] wrote a blog post in January explaining that  a Solar Panel’s Performance actually degrades with temperature. It is the amount of sunlight that determines the power output. If you can get a strong sun without […]

  3. How To Read A Solar Panel Specification: Part #1 Power & Temperature Specs | Solar Power Blog says:

    […] solar panels reduce their power as they heat up. The “Temperature Coefficient of Pmax” tells us how much power it loses for every °C that the panel is hotter than 25°C […]

  4. How Does Temperature Affect Your Solar Inverter Power? | Solar Power Blog says:

    […] If you’ve been reading this blog for any length of time you are probably already aware of how high ambient temperatures negatively affect solar panel performance. […]

  5. East West Facing Solar Panels On A Single String Can Work Well says:

    […] temperatures reduce the efficiency at which solar panels operate and decrease their output. When one set of panels is receiving less […]

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