DCS Batteries Make Wild Payback Claims

DCS battery and Croc Dundee

Australian battery company DCS are making wild claims about their battery.

Power is boring.

But the struggle to obtain it?  That is interesting.

In 10 year’s time powering homes with batteries may be so commonplace it will be boring.

But at the moment it’s not so dull.

One company that is giving people power over their own electricity consumption is Deep Cycle Systems or DCS:

  • DCS are an Australian company located at Mount Tamborine in Queensland, which is the greatest state in Australia1.
  • They have developed a solar battery using proprietary Sino-Japanese2 technology.
  • Their first units were assembled in Australia, but they now manufacture in China.
  • They claim to have over 300 systems installed across the country.

For the benefit of those who may want to get their power hungry hands on them, I’ll tell you what I know about the batteries made by DCS:

The DCS PV 10.0W And DCS PV 5.0W Batteries

Deep Cycle Systems produce the DCS PV 10.0W battery with 10 kilowatt-hours of storage and the DCS PV 5.0W battery with 5 kilowatt-hours of storage.  Their names have the letters PV in them because they are made for use with rooftop solar.  (As for the W, I’m afraid I don’t know watt that could mean.)

They are high power batteries and can be fully charged or discharged in one hour.  This makes their power output 10 kilowatts for the large battery and 5 for the smaller one.

They are lithium iron phosphate (LiFePO4) which is the most durable type of lithium battery and also the safest by virtue of being the least likely chemistry to start shooting out flames.

DCS sells their 10 kilowatt-hour solar battery, including GST, for $10,000.  Their 5 kilowatt-hour battery is $5,900.

They have a 10 year warranty and unlike Tesla Powerwalls, LG Chem RESUs, BYD B-Boxes, and numerous other energy storage contenders, it is a real 10 year warranty that gives enough kilowatt-hours of use to last 10 years when cycled once per day.

For those who want a solar and battery package deal, DCS will arrange for 6.24 kilowatts of solar panels, a 4.6 kilowatt SolaX multimode (hybrid) inverter, and their 10 kilowatt-hour battery, to be installed for $20,000.

Their Technical Specs Are A Bit Technical

I swiped this table of technical information on DCS’s batteries and then scrawled on it in green for the benefit of people who may not know what 1C means3.

Deep Cycle Systems battery specs

Can Be DC Coupled Today

The DCS battery system consists of a weather proof box containing batteries and a battery management system or BMS.  In order to work as a home energy storage system other hardware will be required.

In normal use these batteries would be DC coupled to solar panels using a multimode inverter, also known as a hybrid inverter.  These are more expensive than standard inverters whose modes are far less multi.4

DCS says any inverter that accepts 48 volt batteries will work and gives a long list of them:

  • Victron
  • Schenider
  • SMA
  • Redback
  • Ingeteam
  • GoodWe
  • Sungrow
  • Solax
  • Solis
  • DCS 5kW BMU

Can Be AC Coupled Soon

DCS says they will soon release a version of their 5 kilowatt-hour solar battery that can be directly AC coupled.  Unfortunately, it may be difficult to install under new Australian standards unless your local DNSP allows an exception.

Size, Weight, And Location

Peter Dinklage

“A little person joke? I thought you were bigger than that, Ronald. But then, not many people are bigger than you, are they?”

The 10 kilowatt-hour DCS PV 10.0W is is 55 cm wide and 78 cm tall.  That about as wide as a stove but not quite as high.  At 22 cm it is about as deep as one Pringle container.  And that’s a rubbish modern Pringle can.  When I was younger they were big enough for me to fit my whole hand inside.  Nowadays if I want a Pringle I have to hire Peter Dinklage to feed me.

The 5 kilowatt-hour version is the same size except for the fact that it is smaller.  The height and depth are the same but it is only 30 cm wide. Which is the length of a 30 cm ruler.

Its weatherproof case is made to be wall mounted and can be installed indoors or outdoors.

It Can Handle Extreme Temperatures – But Not According To Its Warranty

The battery’s optimal operating temperature range is 0 to 45 degrees.  And that’s very convenient, making it suitable for most locations in Australia.

But the tech specs give its available operating temperature as -20 to 65 degrees.  While not be optimal, with that temperature range it should work anywhere in Australia5.  I would say it is the best temperature range of any battery available – except for the fact that it’s not actually that good in practice. Let me explain.

On their website they say:

“Widest operating temperature range in the industry”

But its warranty says:

“The ambient temperatures during the operation of the subject of the warranty must not fall below -5 degrees C or exceed 45 degrees C.”

While that’s still an excellent operating temperature range, if you like keeping your written warranty intact, then the available operating temperature range mostly isn’t available.  They should rename that section on the tech specs as “mostly not available operating temperature.”  But it’s still suitable for most locations in Australia as long as it’s not in direct sunlight.

Its Claimed Efficiency Is Excellent

The tech specs give its round trip efficiency as 98%, which is wonderful.  Unfortunately, this is only at 25 degrees and one-third its full charge or discharge rate.  But DCS has informed me that even at its maximum charge and discharge rate, its efficiency will be over 96%.  If it averages 97% and losses from the inverter and wiring knock off another 4 percentage points, then users can expect an overall round-trip efficiency of around 93%, which is excellent.

The DCS Warranty Outlasts Tesla, LG, BYD, And Others

DCS warrants their batteries for 10 years. Unlike most solar batteries either on the market or coming soon, the DCS warranty allows enough kilowatt-hours for it to last the full 10 years even when fully cycled an average of once per day.  The warranty also states the batteries will have at least 80% of their original capacity by its end, which is far better than most.

Minimum battery capacity permitted by warranty chart


The graph below shows how many years a battery’s warranty will last when cycled an average of 0.8, 1.0, or 1.2 times a day, assuming that its capacity declines linearly down to the minimum its warranty allows for by its end.

If the DCS capacity degrades linearly down to 80%, then it will last a full ten years for anyone who cycles them an average of 1.11 times or less a day. Which will be pretty much everyone.


Years of warranty vs. battery cycles per day

It Won’t Save You Money

Despite their excellent warranty, DCS batteries still won’t be able to save households that have remotely normal electricity use money.  This is despite the fact that I expect them to last well beyond their given warranty and longer than any other any other lithium battery that isn’t LiFePO4.

While it is competitively priced compared to other batteries on the market, its cost per warranted kWh is be more than Tesla’s Powerwall 2.  Even taking what Tesla’s says at face value, the Powerwall 2 cannot realistically save people money and so DCS batteries can’t either.

If you are interested in the details, I previously wrote about how the Powerwall 2 is likely to lose money for households.

DCS Installs PV, Inverter, & 10 Kilowatt-hour Battery For $20,000

If you live in the Brisbane, Sunshine Coast, or Gold Coast regions of Queensland, or in NSW or Victoria, DCS can arrange the installation of rooftop solar panels, a multimode inverter, and their 10 kilowatt-hour battery for $20,000 including GST.  The whole shebang consists of:

  • 6.24 kilowatts of tier one Phono solar panels.
  • A 4.6 kilowatt Solax SK-TL5000E multimode (hybrid) inverter with a BMU 5,000 100 amp charge controller.
  • A DCS PV 10.0W battery.  (They say the battery is LiFePo4 instead of LiFePO4, which would make it a lithium iron polonium battery and highly radioactive, but I strongly suspect this is just a typo6.)
  • A 40 amp Automatic Transfer Switch that will activate battery storage within 20 seconds if a blackout occurs.

The inverter can charge batteries with up to 5 kilowatts of DC power but can only provide 4.6 kilowatts of AC power to the home.  When used for back up power it can only provide 4 kilowatts of AC power and DCS recommends loads be kept below 3.5 kilowatts.  While this system can be used off-grid, DCS recommends using a Fronius or SMA inverter for off-grid use to increase the amount of power available.

STC claim limit appears to be breached.

One odd thing about this package is the inverter’s datasheet  clearly states it is a 4.6 kilowatt inverter which means it can be installed with a maximum of 6.133 kilowatts of solar and still receive STCs  (AKA the “solar rebate”).  DCS says the cost of the extra 107 watts that doesn’t receive STCs is included as part of the package.  As it is only a smidgen over the limit, DCS claim it won’t cause a problem. But I have heard of installers having all the system’s STCs knocked back because the installed panel capacity was over the limit by a few Watts, so I’m surprised they have been able to do this.

DCS Estimates Of How Much Money Can Be Saved Are Nuts

DCS describes how much money can be saved with their $20,000 solar and battery package, but unfortunately I don’t find them credible.  They say:

“…you can generate somewhere between $3,285 to $4,380 per year (based on a $0.30 electricity tariff).”

That is completely nuts.  Even if the household self-consumed every kilowatt-hour of electricity the solar panels generated, it would still be impossible.  This is nuttier than the contents of my stomach after I’ve been sitting under a Queensland macadamia nut tree all morning with a hammer and a lump of concrete.

DCS states:

“This system is capable of producing around 30kWh of solar electricity per day on average…”

No it’s not.  Not in the locations they say its available for installation.  Even if you located 6.24 kilowatts of solar panels in Goddamn Longreach, which is located next to Hell, it still wouldn’t quite average 30 kilowatt-hours a day which is needed to get the 10,950 kilowatt-hours a year that would be required to be worth $3,285 if every single one of them reduced electricity bills by 30 cents each, which they won’t.

It’s not easy to find a place sunnier than Longreach.  My cousin grew up there and was 5 years old before he first saw rain.  The sight of it shocked him so much he passed out and they had to throw a bucket of dust over his face to revive him.  So where did DCS get the $4,380 a year figure from?  Well, I’ll let them explain that themselves:

“This system is capable of producing around 30kWh of solar electricity per day on average combined with 10kWh of Lithium Ion battery storage.  Providing a total of 40kWh of electricity per day.”

Now that’s really astounding.  In our universe, solar panels generate electricity and batteries store it.  But in the DCS universe it appears that batteries can generate electricity and increase the total output of a solar system they are attached to.  Maybe it wasn’t a typo when they wrote it was a radioactive polonium battery.  Or maybe they have just made a very silly mistake.

I asked DCS about this and they told me the 40 kilowatt-hour figure is because the solar panels could generate 30 kilowatt-hours and then the batteries could supply 10 kilowatt-hours that were stored the day before.  But that’s not:

“Providing a total of 40kWh of electricity per day.”

And it won’t give their $4,380 figure they got from multiplying 40 kilowatt-hours a day over a year by 30 cents.

Blending Battery And Solar Return Hides Fact Batteries Don’t Pay

The DCS site gives estimates of rooftop solar production in a variety of eastern state locations and these amounts are much more realistic.  They also provide estimates of how much solar plus batteries can reduce electricity bills, but it is impossible for me to work out how they arrived at these figures because they have blended the return from rooftop solar and from batteries together.  This allows the good return from rooftop solar to hide the poor return from batteries.  The moral of this paragraph is, be wary of a salesperson who only gives you figures for solar and batteries together and avoids giving figures for batteries alone.

Caveat Emptor

I mocked what DCS wrote about how much the electricity generated by their PV and battery package would be worth because it soundly deserved mocking.

But more importantly, it is simply unfair to mislead customers with information that is, at best, a mistake resulting from misplaced enthusiasm.  It does their business, and the battery industry as a whole, no good at all.

While they may have the most durable lithium battery available according to their warranty, if your grid electricity consumption is anything approaching normal it is not likely to save you money.

If you are on-grid, I have three pieces of advice:

  1. If you want to save money, install rooftop solar.
  2. If you want electricity during blackouts, buy a generator.
  3. If you want battery storage, then buy battery storage.

Maybe it won’t be that long before battery storage can save money.  I don’t know what the future holds, but I presume I’ll find out in time.


  1. I took a vote and after I had finished counting all the hairy arachnid forelegs raised in the air, Queensland was the clear winner.
  2. Sino is a word people use when they get tired of writing the word “China”.
  3. 1C is of course half an Australian corn chip.
  4.  Some multimode inverters don’t have a battery charger built in so you may need a charger too.
  5. provided it is kept out of direct sunlight in a heatwave and off the top of Mount Kosiuszko
  6. I mentioned the typo to DCS, so it may not longer be there.
About Ronald Brakels

Joining SolarQuotes in 2015, Ronald has a knack for reading those tediously long documents put out by solar manufacturers and translating their contents into something consumers might find interesting. Master of heavily researched deep-dive blog posts, his relentless consumer advocacy has ruffled more than a few manufacturer's feathers over the years. Read Ronald's full bio.


  1. Ray Havill says

    Hi Ronald,

    I enjoy your lighthearted approach.

    I agree ADDING the battery capacity to the Solar production is stupidly unreasonable.

    I have noticed that TOU electricity plans are becoming increasingly common and they generally offer very good off peak rates (8 to 14 c/kWh), reasonable shoulder rates ( 18 – 22 c/kwh) and horrible peak rates 38 – 49 c/kWh (4-8pm Monday to Friday)

    For residential grid connected systems how much would the peak grid rate have to be for the current battery offerings (approx $1000 per kWh of usable per day), taking into account their cycle life and reducing capacity over time,
    to be economic?

    • Ronald Brakels says

      If a DCS 10 kilowatt-hour battery was installed in Sydney on a time-of-use tariff with the following assumptions:

      1. A a weekday peak price of 50 cents a kilowatt-hour and a weekend shoulder price of 19 cents a kilowatt-hour.
      2. A low 6 cent solar feed-in tariff.
      3. It is completely charged with solar electricity each day and fully discharged during the highest price period each day.
      4. Its average overall round trip efficiency is 95%.
      5. It has a lifespan of 15 years.
      6. Its capacity averages 9 kilowatt-hours over that time.
      7. It costs $13,000 fully installed.
      8. The price of grid electricity and the solar feed-in tariff remain constant in real terms.

      Then it would provide just under 4% return a year for 15 years. If it was instead cycled an average of 0.5 times a day, then keeping all the other assumptions the same it would lose roughly $4,400. If we assume the lower average cycles extends its life out to 20 years it still loses money, but only about half as much.

      As no normal home will be able to fully cycle it off solar electricity each day it is still a long way from being economically worthwhile for anyone whose electricity consumption habits are anything approaching normal. If grid electricity prices rise and feed-in tariffs don’t rise by as much then with enough of an increase it could pay for itself, but the time to install batteries in order to save money is when they save money and not before.

    • Ray
      One of the problems with asking Ronald a question like that is that the answer will be different depending on how much of your usage is in Peak, how much is Shoulder and how much Off-peak; and also what state you are in.

      eg In Queensland, Peak is 4pm to 8pm Mon-Fri. In NSW it’s 2pm-8pm

      If you’re out working all day and use little Peak rate power you’ll get a different answer than your neighbour who may use no more power than you but who stays at home and burns a lot of power during Peak time. Your battery would be replacing mainly Shoulder and Off-Peak power, and your neighbour would be replacing Peak power.

      This assumes it’s a cloudy day so you are using the battery you charged yesterday. If it’s glorious sunshine all day then your 6.24 KW of panels may handle nearly all your demands, so your battery does not have to supply much of its stored 10KWh – so it will take even longer to pay for itself (unless the price of electricity has gone through the roof)

      If you want Ronald to work it out, you’ll have to given him YOUR consumption figures – split into Peak/Shoulder and Off-Peak – and recognise the answer will apply just to you

  2. David Knox says

    I love the bit about your alleged cousin in Longreach having a bucket of dust thrown over him.
    We live in a totally different world up here on the Atherton Tablelands, where if it doesn’t rain for two days, we shout DISASTER, we’ve hit the drought season already. But then again, the drought never lasts more than 3 days anyway.
    However with all this rain, our rooftop solar has paid for itself within 5 years.
    From now on we are even-stevens.

  3. For roof safety and also because of shading, I like enphase microinverters – (so I must be an AC-Couple sort of person). If I didn’t care about giving my scumbag DNSP any feed-in energy from my PV (let alone 5kW of it), would those perceived issues of AC Coupling quietly go away ?

    • Ronald Brakels says

      Whether or not export limiting your system so it won’t send electricity into the grid or send more than a set amount of electricity into the grid, will allow you to install more than 5 kilowatts of inverters on a single phase will depend on if your local Distribution Network Service Provider (DNSP) allows it. The new standard doesn’t.

  4. John Relph says

    Hi Ronald,

    I enjoy yours and Finn’s comments, articles etc but I feel Lithium may be a failure overall. I worked with lead acid batteries for 40 plus years and in the GPO Sydney we got 30 years out of two battery banks, we extended the life to 40 years, these were big 2V cells in a 48V configuration. Not long ago, maybe 5 years ago 48V was the norm. I asked for quotes for a battery ready system but when I mentioned 48V 400 AH batteries, SCHOCK!!! You have to use lithium, RUBBISH!!!! I have found a company who will design what I want and expect their quote to be ready next week.
    Battery technology has changed to the better, we even have salt Nickel, FIAMM.
    I am disappointed at the various companies (solar), Are they THICK IN THE HEAD or what? Lots of new high tech things in the battery world are about to happen and the prices will be very much more competitive than in 2017.

    • Trevor Close says

      John, regarding the large 2 volts lead acid cells. Did they get cycled much in their lifetime? I would imagine they were used as a backup power for the telephone system and therefore not cycled. It’s great news that battery technology is evolving, for solar. Only a few years ago no one would have dreamed of electric powered model flight.

    • but how much energy storage is left in a 30 year old lead acid battery bank?
      Answer – very little. Sure a lead acid battery 2V cell can last that long but the efficacy is horrible and they are basically useless after that time. IMO lead acid batteries will be gone in 10 years. there is just simply better battery technology now which continues to get cheaper daily.

    • Tom Courtney says

      On float for 40 years is very different to cycling once a day to 70%
      No way you will be looking at 40 years even with the old Exide 2 volt 400Ah Gut busters, not even 10 years, Go LiFePO4 Prismatic cells Much easier to care for.
      The biggest problem with all these battery systems is the smoke and mirrors of false claims by Manufacturers. Caveat Emptor…. I have a set of 7 year old LiFePO4 Prismatic cells they are at about 80% now. I doubt they will stay at that for the next three years, Who has a Laptop with a 10 year old battery that still holds a good charge, Get real….

      • The trouble with the LiFePO4 prismatic cells is that the main brands like Thundersky and Calb were inferior to good cylindrical cells. Many early adopter EV owners complained about the lifespan and QC. Higher quality cells under moderate 1C max use and cycling could easily last 25 years. Many of the cylindrical cells are rated at 5C continuous and 10C peak with a 2000 cycle life to 80%

    • Jack Wallace says

      Well pointed out John….I’ve been saying the same thing for years. Before Kennett sold of the SEC here in Victoria we could buy those 2-volt batteries for an average of about $12 each from the depot in Port Melbourne. ~ along with a lot of other things.) The batteries were regularly replaced regardless of use, and a friend of mine dumped her battery-bank a couple of years ago after getting 28-odd years out of them: bought second-hand.

      Unfortunately they were never warrantied ~ but it wouldn’t have mattered, since the SEC carked it before they did. In a world where you’re more likely to pay for a warranty than the product you need a lot of confidence the company will be around when (note: not ‘if’) it’s needed.
      Hi-tech is great….until something ~ ANY little thing goes wrong.

  5. Hello, our electricity bill shows we average over 60kwh per day in summer (QLD) – due to a ducted air conditioner – what size system should we be looking at if you say 6.24kw will not produce 30kwh? – because I was thinking of between 6 and 10kw of panels would be ample to save some money? – thanks

    • Ronald Brakels says

      In Brisbane, 6.24 kilowatts of north facing solar panels can produce an average of 25 kilowatt-hours a day. So 10 kilowatts of panels could generate an average of around 40 kilowatt-hours a day. But for the three summer months – December, January, February, the average per day will be around 47 kilowatts.

      You can use the PVwatts site to produce slightly optimistic estimates of how much rooftop solar will generate in your general area:


      Installing 6 to 10 kilowatts of panels will definitely save you money. Larger systems can increase payback times by decreasing the self consumption of solar electricity which reduces electricity bills by more than sending it into the grid for a feed-in tariff. But if you wish to generate as much solar electricity as you can, the maximum amount of panels a home in south-east Queensland can normally install is 6.66 kilowatts for homes with single phase power and 13.33 kilowatts for homes with 3 phase power.

  6. I currently run 4 banks of 48 volt gel cell batteries at 160 AH each through my 6000 watt inverter, the system runs my heating and pumping system for my Hydroponic/aquaponics as well as topping up my solar hot water system. (totally free hot water all year) I also have 5,2 kW array net to the grid and when we have a power outage my batteries automatically run my house for 6 hours before I need to kick my generator in the guts. My batteries are 9 years old and still going strong as my inverter will only accept power over 44 volts DC from batteries. Total solar on my place is 8.3 kW and my last quarterly electricity bill was $32.00 with 10c a kW H into the grid.
    I am interested in a ZCell once the price comes down to make it cheap enough to pay for itself in 7 years.

  7. The warranty says:
    “Maximum warranted kW hours during the Warranty period is the Nominal Energy of the Subject multiplied by 3650 (total amount of days during a 10 year period). For example a DCS PV 5.0 which has a nominal energy rating of 5.12kWh multiplied by 3650 = 18,688 kWh. Should the subject be cycled greater than 3650 and less than 3850 than DCS warrants the subjects nominal energy to be above or equal to 60%.”

    The warranty offers 3650 cycles and 18.68MWh, but if greater than 3650, and less than 3850 cycles, capacity may be 60%. That’s a reduction from 80% to 60%, for no more than an additional 200 cycles?

    Note that the *maximum” warranted storage is 18,688kWh, and that results in
    the 60% figure.

    I would expect that a company making exaggerated ROI claims, may also exaggerate battery performance, but that would by cynical.

    • Ronald Brakels says

      Thanks for catching that, a.thomas. Can you provide a link to that? Currently, I can’t find the warranty on the DCS site.

      • I found it in the comparison table’s link, Ronald.

        At least one Japanese LFP cell manufacturer claims 80% at 10,000 cycles, when their cell is operated at .03C. A token load, where calender life dominates capacity loss.
        I get the impression that DCS’s 80% claim applies to some undefined, but limited use, reducing to 60% when the “maximum warranted aggregate” is obtained.

        Their blog offers:
        “And how hard has the DCS PV 10.0 battery been working during this 31 days? As can be seen in the graph below the battery has only been fully cycled on 2 occasions!. We estimate that Rachel will cycle her battery a maximum of 100 times a year on average. That’s a 25 year life span before the DCS PV series battery arrives at 80% original capacity.”

        That sort of thing – if 25 years were possible.

        • Ronald Brakels says

          Sorry about that, a.thomas. DCS has just made some changes to their site and I wanted to check they hadn’t changed their warranty as well, but we are both working from the same page. The drop from 80% to 60% minimum capacity with just 200 extra cycles does seem odd, especially with their claims that it can potentially last over 20 years and that its decline in capacity will be very gradual.

          • DCS have indeed changed their site. Some of the ROI calculations showing the battery is little used when in a system, have been removed.

            Though 80% is invited, the warranty does not connect aggregate and capacity.

            3. “Maximum warranted kW hours during the Warranty period is the Nominal Energy of the Subject multiplied by 3650 (total amount of days during a 10 year period); For example a DCS PV 5.0 which has a nominal energy rating of 5.12kWh multiplied by 3650 = 18,688 kWh.”

            18,688kWh represents 3650 cycles where 100% capacity is retained. That hypothetical figure is the “maximum warranted kWh”.

            In practice:
            “Should the subject be cycled greater than 3650 and less than 3850 than DCS warrants the subjects nominal energy to be above or equal to 60%”

            If cycled for 3850 cycles, capacity can be equal to 60%. The superflous 3650 figure suggests a relationship to the hypothetical maximum aggregate, and that’s all it does,

            DCS emphasise the long life of the battery. LPF can offer lower calender loss than NMC, and perhaps 80% at 10 years if driven to church only on Sundays. On the other hand, the cells operate at 1C, 100% DoD, so cycle losses will be significant.

  8. Jack Wallace says

    Young Ron, it might be time to shift yourself and the horse out of SA. Even QLD might provide a better environment for developing your cognitive capacity. (‘Arithmetrical skill’.)

    —-> “The height and depth are the same but it is only 30 cm wide. Which is the length of a 30 cm ruler.”
    Any schoolkid knows y’can’t measure Widths with lengths. (Nor oranges with apples.)…Watt??

  9. andrew johnston says

    yer it all seems a bit to much as batts are so deer if they wont every one to use these they should take off all the gst and import duty’s from all solar shit and then it may be worth it and every one just mite take up the challenge i have spent to muck trying to kill my bill and with what i now know and have learned i would never have started

  10. I Love soler says

    Umm, I wish to disagree with your point of not being able to generate 30 kwh / day. I live on the coast in nth Qld. I have 2 systems. One is facing nth nth west and my best is 46.7 kwh for the day with 5kw inverter and 8 kw of panels the other is 4kw on nth west and 3.5kw on sth east and and even it has done around 42kwh. I have paid my systems off in around 3 yrs and will definitely be looking at some sort of battery storage system shortly as I like my air con in summer but still want to export power

    • Ronald Brakels says

      It certainly is possible to get 46.7 kilowatt-hours from a 5 kilowatt inverter and 8 kilowatts of panels in a day. With 6.24 kilowatts of panels that would be equivalent to 36.4 kilowatt-hours. But it’s not possible for 6.24 kilowatts of panels to average that over a year.

      • I Love soler says

        I’m not home at the moment so don’t have the figure to back me up but I only recently added the extra panels and so had 6kw of panels prior to this but from memory I reckon my system would have been in that ball park. From memory I think 43 kwh was the best with the 6kw of panels…Even my installer didn’t believe what it was putting out….Anyways not trying to have an argument i’m just pretty darned excited about my solar systems oh and we get the $$c feed in as well so it’s win win.

  11. Arthur Bradley says

    If they have only sold 300 units so far and make silly claims about their products then I am wary of their claims of battery life which are significantly better than industry averages. It would be quite disappointing if they really do have a good battery.

  12. 2 things

    1) A warranty is only as good as the viability of the company that backs it.
    Given the size of DCS – the length of the warranty – and the likelihood that if their estimate of durability is wrong then they will have a LOT of claims – I would be concerned.

    2) In the spec sheet they say 1C for charge and discharge, but 100A for continuous current at 48V.
    100A * 48V is 4,800 watts or 4.8KW or 0.48C for the 10KWA unit

    10KW is the instantaneous supported draw at that only at 25C for less than 10 seconds

  13. Have 40 panels and electricity is still the same as before I got the panels. I don’t understand any of it so I feel I’m stuck either way. I want to look into getting a battery but I was under the impression it would store my power that is generated through the day for me to use at night. That way I wouldn’t have to use from the grid. My electricity company pay only 6c kw for my solar feed in is that normal? Also do solar panels need to be cleaned? I’ve had mine for nearly 3 years. After paying for 40 panels and to be told I would save on my electricity bill to still get $700-$1000 bills quarterly is an absolute joke. Just under $4000 a year on electricity with 40 solar panels doesn’t seem right to me. I try and look into other electricity companies to see if I could get a better deal but I don’t understand most of it so I have no idea if it’s going to be worth switching or not.

    • Ronald Brakels says

      Hello Melissa

      If your grid electricity consumption is as high as it was before you got solar then it is possible you have a defective appliance such as a leaking hot water system. It is possible there are one or more people in the household who are being wasteful with power. A person I know ended up with a large bill because a child decided to leave a bar heater on in her room at all times.

      A feed-in tariff of only 6 cents is low and you you can use our tool to try to find a better deal:


      But if you have trouble using it just let me know what region you are in and I’ll try to find a decent deal for you.

      A battery won’t save you money at the moment. They still have to come down in price before they are cost effective.

  14. Derek Bolton says

    Hi Ronald,
    (Love your style and attention to detail.)
    Elsewhere on SQ I see a claim DCS (under ideal usage) adds only 20c/kWh, though that’s not including battery inverter.

    Current peak/offpeak differential in NSW runs at 39c. So it sounds like there is a saving to be had for some households on ToU, regardless of PV.
    But this being the case, why are such batteries not being rolled out at, say substations, where full usage would be easier to achieve, as well as other economies of scale?
    Or taken up by businesses, which would additionally benefit from being charged less for peak monthly demand? Maybe the ROR is not high enough for most.

    • Ronald Brakels says

      Hi Derek

      Under the right circumstances it may be possible for a home to save money by charging a battery with off-peak power and then using it during peak periods. But there are several problems that make it difficult. These include:

      – With discounts the difference between peak and off-peak charges may be around 32 cents in Sydney.
      – Peak rates only occur on weekends.
      – There are always some energy losses with batteries.
      – Most households have difficulty using a large home battery at a high capacity factor and smaller batteries have higher costs per kilowatt-hour.

      So while it’s possible some people may find it worthwhile the cost of home energy storage will have to drop further before it becomes worthwhile for normal homes. I go into it in this article:


      Utility scale battery storage at substations or wherever that’s just used for electricity arbitrage (buying low and selling high) doesn’t appear to pay for itself at the moment, but if it’s also paid to supply ancillary services or used avoid costly transmission upgrades it can:


  15. Michael Archer says

    hy Ronald, Thanks for your insightful article.
    Just one question though, why cant you expect 30kw/day from a 6+kw system.
    I have an antique 2.1 kw set that will routinely produce 12kw/day and is shaded out until about 9 in the morning. (Floreat Western Australia)
    My maths figure an equivalent of 28Kw
    Please comment

    • Ronald Brakels says

      Hi Michael

      In Perth a 6.24 kilowatt system can average 28 kilowatt-hours a day but in Queensland solar output, while still good, tends to be lower due to greater cloud cover. In Brisbane it’s about 26 while in Cairns it’s 26.6. As I mention, the system would have to be in a place like Longreach to approach 30 kilowatt-hours a day and give the very specific results claimed.

      Glad to hear your old system is performing well. What type of panels does it have?

  16. John Biasutti says

    Batteries are a great idea! But you don’t need to power your home in the event of blackouts.

    What you need is the lights to work.

    The refrigerator will stay cold for a day. The cooking can be done with gas.

    So a small battery hooked up to emergency lighting in a house (12V circuits) would provide the most effective means of dealing with blackouts.

    For those who are really really cheap there are always candles, these are a couple of dollars for a box of a dozen.

  17. Mal Tones says

    Hi, I see this post started 2017. Do you have any updates on DCS as they now offer a larger battery and I am very interested

    • Hi Ronald,
      Any more ideas on the DCS systems – about to buy a small off grid system and really need help.


      • Ronald Brakels says

        Well, if you go in with eyes open and are happy with what they offer and their warranties, that’s fine. But I’m not familiar with what they are currently offering, so if you let me know what you are thinking of getting I’ll have a quick look. But off-grid is very different from the on-grid systems I am usually looking at, so I may not be able to tell you anything useful.

  18. Bret Busby in Western Australia says

    So, eighteen months later, have they corrected their information, are their batteries any good, and, do they have a battery with capacity greater than 10kWh?

  19. Bret Busby in Western Australia says

    Ah – I got it wrong – it is not eighteen months later – it is thirty months later. Old age has this effect…

    • Ronald Brakels says

      They have changed their line of battery systems. I recall asking at one point if they wanted me to to put a line at the top of the article saying what they offered had changed and I could put a link to what they currently were providing, but I didn’t hear back from them.

      • Bret Busby in Western Australia says

        In looking at the Solar Quotes battery Comparison Table, at
        as it does not at present, appear to include it, I wonder whether adding a row with the label “Manufacturer’s web site” and including a link to the manufacturer’s web site (or, to a relevant web page for the particular battery), would be worthwhile. Where a URL is not available (which, in these times, would be an unfortunate shortcoming), putting something like “N/A” in the cell, would be appropriate.

      • Bret Busby in Western Australia says

        There is this;
        and this;
        but, without the latter one providing no explanation otherwise, I assume that the “Nominal Discharge Current” values specified, mean that the 13.5kWh battery will only, despite the “Continuous charge/discharge current” value, discharge at up to 3.75kW, and, with the “Long Term Storage Temperature” range of “0-30C”, I assume that the batteries are to be installed and kept in coolrooms, and are otherwise unsuitable for use in Australia, where temperatures between September and may, often exceed 30 degrees centigrade.

        As the batteries are expected to last, in use, for more than three years, I expect that installed usage lasting for more than five years, should be a scenario to which the “Long Term Storage”, and, therefore, the “Long Term Storage Temperature” apply.

        I note that the price for the 13.5kWh battery, as advertised on the DCS web page, is now “$10,750.00 AUD” (which should just be “10,750.00AUD”).

        So, the battery comparison table, could be updated, to include the current advertised price (which may change the “Cost per Total warranted kWh (1 cycle per day)” in the table?)

        Also, in thinking about it, does the “Cost per Total warranted kWh (1 cycle per day)” in the battery comparison table, take into account, both the Depth of Discharge, and the expected degree of degradation, over the warranted lifetime, of each battery in the table?

  20. Bret Busby in Western Australia says

    I notice that the DCS batteries appear to have been removed from the table at

    To quote the famous Julian Siumner Miller (?), “Whis is this so?”

    Have the DCS batteries ceased to be available?

    I note that they are still advertised, including a 15kWh model, at
    with a price of 9890AUD plus delivery (and installation).

    • Bret Busby in Western Australia says

      Ah – two typo’s – “Siumner” should be “Sumner”, and, “Whis” should be “Why”.

  21. Bret Busby in Western Australia says

    I note that, on the web page at
    the 15kWh battery is phosphate based, rather than using polony (as mentioned in the above article, for the smaller batteries).


  1. Is it time to get a battery for you home? – Jonathan Prendergast says:

    […] Finn Peacock from Solar Quotes recently wrote, one day in the future, everyone will have batteries in their home, and by then, […]

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