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Solar storage batteries: Tesla Powerwall and 17 others put to the test


An independent trial of 18 solar power batteries has been running in Canberra since 2016 to see how well they meet their performance claims over time. Batteries from Tesla, LG Chem, Alpha ESS and others were put to the test by ITP Renewables, and not all survived. Check out the summary here:


What a great project being run by ITP.

Reading that ITP has had numerous issues with most of the battery installations, and that several of the suppliers/batteries are no longer available, suggests the market is far from mature. Although notably several major European PV and battery storage suppliers in their public marketing material suggest otherwise. Interesting also that one of the two Tesla Powerwalls has also needed to be replaced during the trial.

Cycling each system several times a day is a stress test unlikely to be recreated in the home, but a great way of accelerating the results.

The one caution not noted in the summary reports concerns a test result based on a sample of ‘ONE’. Any battery model successfully passing the test will have demonstrated it’s potential to be reliable. Any battery model that has developed a fault is not necessarily reflective of every battery in that production batch or design.

By the time the three+ years tests reach completion, the batteries at market to consumers are unlikely to be identical to the models obtained for testing.

I can’t see how the results will be useful in choosing with a high degree of confidence a reliable product suitable for residential use. The results so far suggest anyone investing in residential batteries need to be assured of the warranty and technical support for the typical ten years of expected battery life.

I wonder what cost reliability/failure replacement insurance to cover a home install for ten years might be?


Thanks @mark_m. I’m glad you’ve found the article interesting. You’re right that the trial has some limitations. It is a test of one sample of each model (not counting replacement samples), but so are almost all CHOICE reviews - it’s of course impractical and expensive to test multiple samples for almost any review, whether it’s storage batteries or toasters. And even with an accelerated test program, products are often out of date at the end of the test (same problem we faced when testing lightbulbs, for example). This trial can be seen as a test of the state of the market as much as of individual products. It’s for that reason that we decided not to make specific brand or model recommendations at this stage, though the broad conclusion is clearly that a major brand with strong warranty support is the safest way to go for consumers.


That is a reasonable approach for Choice to adopt.
The typical Choice tests are about safety, user features or controls, performance and suitability for the task, etc.

For a home storage battery system, many of the features or details are remote from the user in an everyday situation. For most homeowners a battery system that operates without any need for attention, faults or checking, IE invisibly, might be the “holy grail”. The core promise is technical performance to specifications, delivery of capacity and reliability over time.

The battery testing Choice has presented is certainly useful in understanding the market and products are not without risk.

If we look to other Choice reviews and consider reliability, Choice falls back on the annual member surveys to report brand and product line reliability. It is a massive data base of committed members.

The Choice header " The best solar storage batteries: Tesla Powerwall and 17 others put to the test", does not hit the mark. Reading the content helps clarify and guide any decision for anyone ready to splurge on a battery system.

Is there really a best battery, given the discussion of a sample of one?
Fine for a basic performance test of a washing machine, but not for a reliability trial that is not statistically significant. Reading the content helps clarify and guide any decision for anyone ready to splurge on a battery system.

Hopefully Choice can include residential home storage batteries in the reliability surveys to complement the ITP progress reports. This might be the one big step Choice can make to provide the best information on how reliable and well supported each supplier, installer and brand are on the day! Members only?


I am quite uncomfortable about the number that failed or had to be replaced. In crude figures only about one third have had no problems so far. The numbers are probably too small to say much about individual makes or models and as you say the market is moving very fast. Nonetheless as a sample of the market at a point in time the failure rate is alarming.

I am reminded of senior IT manager who was always getting presentations of the latest hardware or software. One time the salesman concluded his spiel with “this has only been out for weeks it is leading edge equipment”. The manager replied “you mean bleeding edge”.

It is not amazing to find that such batteries only have quite short warranty periods in comparison to their anticipated (prayed for) working life.


As the manufacturers’ claims usually go, if it has been announced to the market it is state of the art but its real qualities (or lack therefof) behind the hype are unknown. It could still be a pen and paper exercise; there might be a prototype undergoing evaluation; it could be in stages of manufacturing engineering; it doesn’t exists in a practical sense.

If you can place a firm order it was once state of the art and might still be for another few weeks. A newer ‘more advanced’ product has been hyped and will be announced shortly.

If you can ‘hold it in your hand’ it is one or more generations old.


And once the sale was done the sales person collected commission for a job well done, and moved onto the next ‘Wally’?

Shades of the same in the Residential Solar Power Industry. With a battery system selling for typically the cost of a second car how good are the consumer protections?

Choice does a great job with consumer advocacy. More battery systems will follow the great residential solar panel uptake. Seeing Choice involved at this stage of the emerging battery storage market is good news.

Perhaps there is a gap for Choice to fill given the industry already has issues? The one aspect not covered is no one is naming the installers or brands with poorer outcomes. An aspect of consumer education Choice has not been backward in doing for other services and products.

Please excuse Finn’s blunt pointed language commenting on the PV industry as a whole.


Yes it does.

We (and media) seem to believe the marketing spin of the benefits of batteries, however, if their reliability is an issue then it is concerning as it will not only damage the reputation of all batteries (even the reliable ones) and result in poor environmental outcomes (waste of energy and resources).

Batteries have been spruiked as a quick fix, but at this stage from Choice’s (ITP’s) appears there may be more that may meet the eye.

Edit: Maybe Choice should look at doing a customer survey of residential battery systems to see if their poor delivered and installed battery experiences is representative to that in the market place.


Thanks for comments so far. @phb and @mark_m, I am keen that we survey our members (or the public) about reliability of solar storage batteries, but the market is too new and the number of people owning these products is probably too low to get the same kind of analysis that we get with more routine appliances such as fridges and vacuum cleaners.

We did a member survey on solar systems last year, which measured reliability and satisfaction with the systems, components and the installers. Only 9% of respondents (i.e. fewer than 100 people) had a battery as part of their system. We were able to measure the interest in and attitudes towards batteries, but there wasn’t enough data to measure individual brand reliability.


You are welcome. Perhaps for further consideration?

A sample of 100 is far greater than the one of each type currently with ITP Renewables.

Even independent of brand or supplier, knowing the frequency of problems across the sample would be indicative of what new users might expect?

If the data suggests xx% of owners have had battery issues irrespective of brands it helps make a more informed decision to dive in or wait if the upfront cost and payback is not a major concern.

The second general result might be the reliability and type of system controller/inverter (IE Hybrid or separate, AC or DC coupled)?

Choice does not need to make a recommendation on the best battery product. It has chosen not to with the ITP report. However given the rate of change and development and very high investment value compared to a stick blender or fridge, it would appear an important target.

Simply knowing the range of brands actually purchased and system sizes installed is also useful. In particular as a base line and for Choice to build on.

Alternately Choice might be able to negotiate access and publish the detailed industry reliability and performance data for battery systems by brand and age and actual faults. To date these appear to be protected from general consumer view. Not something that should be hidden. It is not likely a matter of national security, just yet? :thinking:

Nationally the number of systems is statistically significant, is it not?


A great article and research by ITP on the facts on solar power batteries and their performance in the real world however, from a personal perspective I noticed that Enphase was missing from the list.

We have a solar array of 5kW which consists of 20 x 250 Watt panels running off 20 Enphase Microinverters and we were planning, when costs were justifiable, to install the Enphase AC Battery system which is modular and can be added to at any time.

This is a direct add-on to our current setup without the need to swap out inverters or any other component thus eliminating any nasty surprises.

The specs for these batteries on the Enphase website are impressive so it would have been nice to see how they would have performed in real world testing.

I have included the link below for those that are curious or just want to know about the Enphase storage solution or Enphase products in general.

Again a great article and research by ITP and it’s understandable that there are only so many products you can test so there is always going to be some that get missed.



hi Nickh64,
I also installed an Enphase micro Inverter system (6.6kw) last year, March.18 -
… I looked at the Enphase Batteries Dec.17 when I was “Ordering” but decided their capacity was too small - I think it has increased since then .… … I installed a Tesla Battery in May.18-

I agree with Mark- more results from ‘current users’ - most of us could provide ‘stats’ on ‘Solar Production’…



I agree with Mark also happy to go down that path as our previous 3 bills have all been credits with the last one being just 2 weeks ago and, with our average back to grid output being anywhere up to 2800kW during the peak summer period quarter we again considering battery storage.

Just a couple of questions.

  1. How easy or difficult was it to integrate the Tesla Powerwall to the Enphase microinverters?
  2. When the sun goes down I assume that everything runs off battery if they are charged but is it set up to run the house in a total power blackout?



Hi @nickh64. ITP advises that they did look at including an Enphase battery system, but identified some technical issues with controlling the charging and discharging in the same way that they do for the other batteries in the trial. They are still keen to include them in a future phase and are talking to Enphase about that.


As far as I am concerned, the main technical problem with them (very high cost per kWh is another “problem”, IMO) is their extremely limited max discharge rate. They may have changed specs recently, but last I checked they could only discharge at a rate of 270 watts, so you would need 9 or 10 of them just to run a 2.4kW electric jug!


Once again Standards Australia is attempting to impose rules that will prevent battery installations in domestic residences. It happened a couple of years ago, and it appears they are at it again now.
With their proposed siting clearances and fireproofing requirements, it will be very difficult to find an allowed location in many houses.


Here’s a good article from Finn Peacock on Solar Quotes Blog regarding batteries, and why they are not necessarily a good idea for many people. He goes into some detail about the mistakes many make when deciding to buy a battery.


With all the great work it does, creating Australia specific standards, many have a focus towards consumers - read locally specific needs.

Does it make us all safer?
One argument is that if by spending a billion dollars more on additional compliance saves just one life a year it is worth it, and you can’t put a value on a life. However life is not without risk. Insurers existence depends on that simple fact!

Optionally, there may be more important things to spend our limited finances on. That is not for Standards Australia to decide?

Without a reliably developed and audited public cost benefit analysis the consumer is left to ponder whether Standards Australia has delivered what is really needed. Yes, SA will have a supporting risk assessment.

The second step in this is each time similar decisions are made is the cost risk benefit comparable with every other community based decision pending standardisation? Transparency and reason needs to apply in consideration of the cost burden on everyday simple living expenses.

We seem to be able to have a house full of other lithium technology based rechargeable devices, all of which have a potential to start fires. It is a risk already recognised and accepted.

Perhaps a fire detector in the Solar Power battery system, interconnected to the Qld Govt legislated all of house smoke/fire alarm system might be a better solution. And a simple do not install the battery immediately next to your only escape route?

For a better understanding of why Australia is different in this instance. Perhaps as one Solar Quotes tech head jokingly puts it, the electrons spin in the opposite direction down under! :rofl:

I eagerly await the realisation by Standards Australia that motor vehicles can exceed the typical upper speed limit of 110kph.


Standards Australia rules could be our equivalent of the many different local regulations in the US about solar, that do nothing but protect the utilities and their shareholders. Solar panels are illegal in some jurisdictions in the US, resulting in the ‘tile look’ low efficiency panels on the market - just the beginning of indirect pushback.


I’d not be surprised if a notable subset of standards that actually benefit from consideration of ‘local factors’ exists, but I’d also be interested in a realistic assessment of how many ‘Australian Standards’ do nothing more than reinvent the wheel. Where there is emerging technology I imagine there could be more benefit, assuming it is emerging in all places where it exists on the planet and not that Australia is just slow off the mark (ie just emerging here) - Solar/etc might fit into this category to some degree. Motorcycle helmets would be a textbook case of where Standards Australia should have adopted already more than adequate overseas standards long ago - thankfully this is happening …

A very slippery slope … the law of diminishing returns promotes the misuse of the public purse? Though with the prices Standards Australia charge for their work I’d expect they’d be making billions :wink:

I’m sure common sense will prevail … :rofl:

Don’t hold your breath !!!