Poly vs. Monocrystalline Solar Panels – Let’s put this argument to bed!

One steaming pile of Solar BS that you hear all the time from worst sales people in this industry – who will feed you any line to get a sale – is that polycrystalline panels are better than monocrystalline solar panels, or vice versa.

In this video I finally get off my chest why you should avoid anyone spouting such drivel:

Transcript follows if you don’t like listening to angry, sweary solar geeks, and I go into great detail about the two technologies over on the main site:

More info on the main site:

And the video transcript is here:

Hi! I’m Finn Peacock. Here’s a sticky question, what’s the difference between the three major solar panel technologies; that is mono-crystalline, multi-crystalline or poly-crystalline (same thing) and the wild card: thin film solar.

Let’s start with mono-crystalline and multi-crystalline, it’s an easy answer, there’s no difference! I say that because I get emails all the time, “oh this solar sales guy that sells mono-crystalline solar panels, he tells me that multi-crystalline solar panels are crap.” And I hear exactly the opposite from the guys that sell multi-crystalline solar panels they say, “oh this is better for Aussie conditions, that’s better for Aussie conditions”, pure bullshit!

Ten years ago, this might have been true, I won’t go into details, but solar panel technologies have come on. A good mono-crystalline solar panel and a good multi-crystalline solar panel – to all practical purposes – perform identically, so don’t get hung up over mono or multi, mono or poly. Just get a good brand of solar panel, okay.

Where there is a difference between solar panel technologies is thin film solar, thin film solar is a completely different way of making solar panels and I’m not a big fan of them, I’ve got to say. For a start, they have half the efficiency, which means that they take up twice as much space on your roof, so you need a huge roof to get any decent size solar system. One of the advantages that people claim for them is that they’re shade tolerant – that winds me up. There is no such thing as a shade tolerant and solar panel! If you have a solar panel and it’s in shade, I don’t care what technology there is, you ain’t gonna get any electricity because there’s no sun shining on it.

What they are trying to get at is it’s more tolerant to partial shade. So, if you cover 40% of a thin film solar panel with shade, you get a proportional power hit, so you’ll lose 40% of your power. If you cover 40% of a mono-crystalline or poly-crystalline solar panel with shade, you probably lose almost all the power of that solar panel. But you got to ask yourself, why you’re installing a solar panel in an area that gets some of shade anyway? That’s insane, you’re gonna take a massive hit to your power.

So yes, thin film solar panels are more tolerant in partial shade, but I still think they are a waste of time! And I get into trouble for saying that!

If you want to read my other thoughts on thin film solar panels and the problems with them, there’s a blog post there where I give them really good bagging.

But in practical terms the difference between the main technologies: mono-crystalline, multi-crystalline, there’s no difference.

About Finn Peacock

I'm a Chartered Electrical Engineer, Solar and Energy Efficiency nut, dad, and founder of SolarQuotes.com.au. My last "real job" was working for the CSIRO in their renewable energy division.

Comments

  1. Graeme Hortin says

    Mono
    Multi /Poly
    Thin Film Solar

    Finn old son, there is no Multi Verses Poly argument. Muti/Poly are the same thing. In Solar we have the three options listed above. Degrees of ambiguity are also unavisable in accurate reporting.
    If you must put pen to paper and call yourself a reporter , then try to report the facts, and report the facts clearly.
    Cheers
    Graeme Hortin

  2. Adriaan Bruins says

    The person who invents a standard roof tile with a built in solar panel economically will steel the market. Mounting solar panels on tiled roofs seems problematic. Adriaan Bruins.

  3. Mono does produce higher output per area over poly.
    Poly crystalline are cheaper to manufacture, as mono crystalline cells are cut from one large crystal whereas poly are made up of multiple, smaller crystalline structures (hence the different patterns you see shining from it)

    Hate thin film, its cheap, but takes up stacks of room, they are heavy and sometimes have a fault and a section explodes when first in the sun. (ive installed for years and seen it happen)
    If you have a giant roof in full sun you may as well go for it though. Its a pain for the installers, but alright for the customer (if they do it properly)

    Which is more cost effective is another story though. Id still go Mono any day over the others for the same price. And i know they hold higher efficiencies over time.

    If youre not fussed about reliability in 20 yrs time though go whats cheaper. You are better off going more KW of cheaper panels, paying itself off sooner and getting into profit who cares if efficiency is bung in 10 yrs. (seems slack, but it works out better)
    In 10-15 yrs youll want a new system anyway as everything will be better and cheaper.

    • Thank you Alex
      You took the words right out of my mouth.
      That’s what I was taught in renewable energy school many years ago. It’s always about the finance and break even point.
      Thin amorphous film panel output is supposed to increase with age and heat where as output on mono/poly crystalline panels loose some output with heat and time.
      Most panels these days have bypass diodes to help with partial shading so you don’t looses all the output.

  4. I’m looking for a solar system to run my 25ft camper. From what I’ve been reading the mono is the way to go. Will a 100W 12 volt monocrystalline solar starter kit run my water pump, air, lights?

    • Ronald Brakels says

      Hello Shannon. I’m afraid a 100 watt panel will only be enough to run a limited amount of appliances. While LED lights might only use 4 watts or less each, a sink water pump may use 40 and a shower water pump will use much more. A tiny evaporative cooler may only use 40 watts, but a large air conditioner can use 1,000 watts. A 100 watt panel attached to the top of a roof may charge a battery by an average 0.3 kilowatt-hours a day. That’s enough to run lights, a laptop, and occasionally use a water pump, but I’m afraid you wouldn’t be able to do much else.

  5. Ian Sansom says

    Hi, we had a solar array installed in Garran, ACT by ActewAGL in November as part of a subsidy scheme. It has 20 Trinasolar 60 cell Honey modules with a Solax X1 5.0 kw inverter with MPPT, divided into arrays of 13 on the north roof face and 7 on the west roof face. We hadn’t planned it at the time, but we have now built a pergola on the north side of the house, supported on the roof face above the eaves and close to the bottom of the first row of 11 solar panels. The steel support beam, running the length of the panels, casts a continuous shadow on the lower 5-10% of the panels during winter, until after midday. In summer the sun will probably be too high to cast a shadow. I have phoned ActewAGL numerous times to ask if the original installers can come and move the panels up, but with no replies after 4 weeks of messages. Would micro inverters or PV or Maxim optimisers minimise this problem and save moving the panels, given that they would be unaffected in summer when the main load is our pool pump. If so, can you recommend installers? I would really appreciate any advice you can give. The ActewAGL installation looks far more professional than the one in our previous Sydney house, but clearly they are not the slightest bit interested in a minor, fiddly job.

    Thanks, and a great web page, which I often refer to.
    Ian

    • Ronald Brakels says

      Hello Ian.

      Your most reasonable options would probably be to:

      1) Move the panels higher if there is room for them.

      2) Place DC optimizers on the panels that get shaded so their poor performance won’t affect the others in their array.

      3) Replace the shaded panels with panels that use Maxim Integrated style optimisation (eg. Jinko Maxim panels.)

      You could also consider if you wish to add more panels to compensate for the reduced output of the shaded ones, assuming they are left where they get partially shaded.

      You will need an experienced installer to look at it to know which is the best option. If you email me your details I can pass them on to a local installer. But, I will warn you, the work could be quite expensive.

  6. Ian Sansom says

    Hi Ronald

    Thanks for your greatly appreciated advice. Moving the panels could be difficult because the top two panels in the array are on the roof ridge line. Since the panels are almost brand new, I can’t afford to replace them, so option 2 may be the most affordable compromise, although I’d be happy to get a quote to have them moved. We are a retired couple with a washing machine and dishwasher, plus the usual electronic/entertainment appliances. Hot water and heating are both gas. The panels are shaded for less than half the day in winter, and almost unshaded in summer, when we run a pool pump. The western array is unshaded so we would be willing to compromise and loose a bit of energy in winter. Any installers you can suggest would be greatly appreciated because, as mentioned before, numerous phone calls and emails to ActewAGL have been ignored. Thanks again for the advice

    • Ronald Brakels says

      I have passed your details on to Rob who will be able to put you in touch with an installer.

      One option I did not mention earlier is, because the panels are only shaded some of the time, put up with the loss in output and use the money you save by not fixing the problem on energy efficiency, as that may be a more cost effective way of reducing electricity or gas bills.

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