sonnenBatterie Evo. Finally! A Decent Battery From sonnen.

sonnenBatterie EVO battery review

The sonnenBatterie Evo. You could install it in the middle of a field – but think of the voltage-rise!

Just the other day, Finn was having a whinge about sonnen batteries.  He mentioned a few problems the current sonnenBatterie Eco has:

  • You can’t install it outside without a protective cabinet.
  • Its power output is low compared to similar-sized batteries.
  • Backup power is an expensive optional extra.
  • Even with the backup option, it can’t charge from rooftop solar panels when the grid is down.
  • It’s expensive.

But now, less than a week later, sonnen has launched their new battery — the sonnen Evo.  It mostly addresses these concerns — except for the last one.  Sonnen gave no pricing information at the launch.  But as Sonnen has always positioned itself as a premium brand, it’s not likely to be cheap.  

Update December 7th 2021: Sonnen has told me they expect the sonnen Evo to cost around $14,000 including installation, which is a much better price than I expected.

The sonnen Evo has the following features:

  • 10 kilowatt-hours of usable storage.
  • 5 kilowatts continuous power. 
  • AC coupled — this lets it work with any solar power system or no solar system.
  • Built-in backup can provide 5 kilowatts of continuous power.
  • The battery can charge from solar in a blackout, but only if the solar power system is 6 kilowatts or less.
  • A warranty that will last any normal household a full 10 years, while retaining a minimum of 80% of original capacity.  This is much better than most lithium solar battery warranties.

Update December 7th 2021: Sonnen has told me the sonnen Evo can be used with Virtual Power Plants (VPPs) other than those offered by sonnen and not just their own, as I originally had written.

Sonnen says the Evo battery should be available in early 2022. 

What Is sonnen?

Sonnen is a German company founded in 2010 that’s been making home battery systems for over 11 years.  They supplied the first modern home battery systems for on-grid use rather than off-grid.  They were originally called sonnenBatterie but shortened it to sonnen, so they don’t have to pay as much when sending a telegram.  Their name doesn’t start with a capital letter. That’s because, before 1990, Germany had two capitals and reduced the number of capitals in the German language to compensate.  

The sonnen Evo also has a longer name, the sonnenBatterie Evo, but try not to use that when sending a telegram.

Imported From Germany

The sonnen Evo is imported from Germany.  Sonnen won’t assemble it in Adelaide despite all the support they received from the South Australian government to set up a factory here.  At the battery launch, sonnen said they would keep that capacity for “future use”.

I could have told the South Australian Government not to spend valuable resources attempting to set up battery manufacturing in South Australia.  (In fact, I think I did.)  While they should welcome any solar battery manufacturer who wants to set up shop here in SA, they should treat them the same as any other business.  This is because we live in a world of limited resources, and it’s not possible to give more resources to one business without reducing the resources available for everyone else. 

Governments should stick to what they are good at which is punishing bad things, not promoting good things.  This is why the police are in charge of catching bank robbers, and families are in charge of Christmas presents. 

Components Made All Over

At the launch, they didn’t say where the sonnenBatterie Evo’s battery modules are manufactured.  But unless they’ve changed their ways, sonnen will source them from two high-quality battery manufacturers in China1.  The battery inverter probably also isn’t made in Germany, but elsewhere in Europe.  Other components could come from all over the place.

This is not a problem.  These days a successful international company can successfully source high-quality components from around the world.  Companies that pull it off should be boasting about it, not hiding the fact.

sonnenBatterie Evo Tech Specs

Currently, there’s no datasheet available for the sonnen Evo. 

Update December 7th 2021: The datasheet is available here.

But sonnen presented slides with technical information at the online launch, and I’ve scattered them through this article.  Here’s one giving an overview:

sonnenBatterie Evo technical specifications overview

Battery Capacity

The battery has a total (or nominal) capacity of 11 kilowatt-hours.  But to protect it from capacity loss, its maximum depth-of-discharge is around 91%.  This makes its usable storage capacity 10 kilowatt-hours.  It should stay reasonably close to that amount within its warranty period, as sonnen promises it will maintain at least 80% of its original capacity. 

If more storage is desired, up to three sonnen Evos can be used for a total of 30 kilowatt-hours of usable storage when new.  It’s possible to add even more if a device from SwitchDin or another manufacturer is used to manage them. 

Update December 7th 2021: Sonnen says it’s not necessary to use SwitchDin to go over 30 kilowatt-hours of storage, but it can provide benefits.

Evo Battery Modules & Chemistry

The sonnenBatterie Evo has two 5.5 kilowatt-hour modules.  Here’s the information sonnen presented:

sonnenBatterie Evo battery module specifications

Lithium Iron Battery Chemistry

The battery chemistry is lithium iron phosphate (LiFePO), or just lithium iron for short.  This is the safest lithium battery chemistry.  This doesn’t mean batteries using this chemistry are safe; it just means it is easier to make lithium iron batteries meeting a high standard of safety than other types.  If a battery module manufacturer and/or battery system producer don’t ensure they are safe, they won’t be.  But I definitely expect sonnen batteries to be low risk.  They have a good track record of not burning down homes in Germany. 

Lithium iron batteries don’t use cobalt.

At the launch, they made it sound like they were doing us some big favour by not including cobalt because:

  • It’s toxic.
  • It may not be mined ethically.

But using iron instead of cobalt for stationary storage is both cheaper and better.  While cobalt2 can allow batteries to be more compact, sonnen would have to be drongos to use cobalt in a battery made to be installed outside. 

sonnenBatterie Evo Power

The sonnen Evo can supply 5 kilowatts of continuous power.  Like pretty much all lithium batteries, it can also – briefly – supply more.  Its 5 second surge capacity is 7.2 kilowatts, and it can supply 8.6 kilowatts for one-tenth of a second. 

If the battery is new with 10 kilowatt-hours of usable energy storage, it will provide 5 kilowatts of power for up to 2 hours. 

AC Coupled

The sonnenBatterie Evo is AC coupled.  This means it operates independently from the solar system, so it doesn’t matter what type of inverter your solar power system has.  It can also be installed in homes without rooftop solar panels.   

sonnenBatterie Evo power unit specifications

This is the sonnen Evo’s power unit, which includes the battery inverter.

Sonnen Evo Efficiency

At the launch, we were told the sonnen Evo’s inverter efficiency is 94.4%. But this is not the same as the battery system’s round trip efficiency, as it only represents energy going one way.  If we assume the efficiency is the same when the battery is charged and discharged, the inverter’s round trip efficiency would be 89.1%.  But there are also energy losses from the batteries, electronics, and cooling fans.  This means the total round trip efficiency of the sonnenBatterie Evo will be significantly less.  Possibly much less.

I asked what the round trip efficiency was…

But sonnen didn’t answer the question. 

In the latest report from the Canberra Battery Test Centre, the sonnen Eco was found to have a round trip efficiency of about 80%.  The sonnen Evo may do better than this but, unless I hear otherwise from Sonnen, I would not expect it to be above 85%.

Operating Temperature

The sonnen Evo’s operating temperature was given as -10ºC to 50ºC.  This is a good range for Australia.  Some batteries conk out at 45ºC, which is a problem because severe heatwaves are when power is needed most.  So far, no Australian capital has ever hit 50 degrees, but it may only be a few years before this changes.


Sonnen gave no information on noise output.  The sonnen Evo has cooling fans, so I don’t expect it to be completely silent when they’re operating.  But I do expect it to be fairly quiet.  After all, there are a lot of sonnenBatteries inside homes.   

The cooling fans are claimed to last 60,000 hours.  As they may only be used a few hours a day, if that’s true, they should have no problem reaching the end of their warranty. 

Outdoors Installation

The system’s Ingress Protection rating is IP56 which makes it suitable for outdoors installation.  This rating means it’s able to resist strong jets of water.  I definitely don’t recommend hosing it down, but if someone did do that, both the hoser and the hosee should be fine. 

This IP rating is a big improvement on sonnen’s previous batteries, which had to be installed indoors or in a separate expensive, industrial, steel cabinet.

EVO Battery Dimensions And Weight

The image below gives the sonnenBatterie Evo’s dimensions and weight:

sonnenBatterie Evo installation specifications

The system is made to sit on the ground and can’t be wall-mounted.  We weren’t told what kind of clearances around the unit may be required.

Sonnen EVO Backup

Unlike their previous home batteries, where backup capability was an expensive additional extra, every sonnen Evo has backup built-in.  It can supply 5 kilowatts of continuous power during a blackout, the same as in normal use. 

But it will only be able to charge the battery in a blackout using solar power if the solar inverter is 6 kilowatts or less on the same phase as the sonnen Evo.  

The battery has a black start capability that you can use during a blackout (if you have 6 kilowatts or less of solar inverter capacity on the backup phase).  If the battery is flat, and the panels are producing enough power, a button on the unit can be pressed that will cause the battery to start charging.

When a blackout occurs, the change over to battery backup won’t be instantaneous.  Sonnen said the delay should be under a second. 

sonnenBatterie Evo backup specifications

Backup Power To 1 Phase Only

The sonnen Evo is a single-phase battery. Most homes only have single-phase power, so this is not a problem for them.  For homes with three-phase power, it’s also not a problem in normal use. 

As far as your electricity bills are concerned, it will operate the same as if your home was single-phase.  But during a blackout, the sonnenBatterie Evo will only supply power to the phase it’s connected to.  This means all your essential loads will need to be on that phase.  It also won’t be possible to run three-phase devices, such as many large air conditioners or three-phase solar inverters from backup power.

If a property has three-phase power, it is possible to put a sonnen Evo on each phase, but obviously, this won’t be cheap. 

Excellent Warranty

The warranty document isn’t available yet, but sonnen said the warranty is 10 years or 10,000 cycles — whichever occurs first.  As no normal household will ever come close to cycling the battery over 1,000 times a year, the warranty should last the full 10 years.  It also promises the battery will retain at least 80% of its original capacity.  This is excellent. 

Some battery warranties won’t last a household a full 10 years if they cycle it an average of one per day, and most lithium battery warranties only promise they’ll retain 70% or 60% of their original capacity. 

Virtual Power Plants (VPPs) allowed

Update December 7th 2021: Sonnen has told me the sonnen Evo can be used with any VPP and not just with sonnen’s VPPs as I had originally written.

sonnenBatterie Evo Price

At the battery launch, sonnen gave no prices, but this One Step Off The Grid article suggests a sonnenBatterie Evo will cost around $14,000 before installation.  While sonnen says the installation will be easy, it can still easily add a couple of thousand dollars to the cost of a battery.  This is because it has to cover not just the cost of installing it but also after-sales service.

Update December 7th 2021: I’ve been told by sonnen they expect the installed cost of the sonnenBatterie Evo will be around $14,000.  This can depend on the property’s characteristics.  This is a much better price than I expected.  

Evo A Big Improvement

The sonnen Evo is clearly a large improvement over the company’s earlier offerings thanks to:

  • Ability to be installed outdoors.
  • An increase in continuous power output to 5 kilowatts.
  • Built-in backup.

So if you have 6 kilowatts or less of solar inverter capacity or less on the phase you want backed up3 then the sonnenBatterie Evo may be a good choice for those who don’t mind paying a premium for a well-built battery system with a good warranty from a company with the longest track record.


  1. It’s common practice for companies to have more than one supplier for vital components. Otherwise, one factory fire or bribery scandal (in some countries, officials are scandalized if they don’t receive bribes) can wreck your business.
  2. Cobalt is German for goblin.  This is because, a long time ago, German miners used to blame cobalt contaminated silver on goblins.  But they haven’t done this for weeks now.
  3. Or don’t mind if the battery can’t charge from solar when the grid is down.
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. Very interesting. On the latest battery testing results didn’t Sonnen perform the best?

    Also, aren’t the batteries they use Pylontech?

    Lastly, These specifications are a long way behind the newer Power Cap graphene supercapacitors which have a 20 yr warranty with zero degradation, and virtually zero risk of fire. (They do have a little bit of lithium in them to reduce any self discharge)

    Have you seen, tested or investigated these?

    • Joseph King says

      This Pylontech sounds interesting. I had a quick Google and if I have read the stats correctly I could have a battery that was twice the capacity of the our 10kWh LG for the same price. I would have liked that.

    • Ronald Brakels says

      If you are referring to the Canberra Battery Test Centre, their sonnen Eco developed a fault and so didn’t do well:

      Last time I was present when sonnen gave information on how they sourced their batteries they didn’t say who they got them from, but — if you believe the warranty — sonnen uses great batteries and pylontech are great batteries…

      So far I’ve not been impressed with the prices or real world performance of any batteries described as supercapacitors. They may improve, but I’ll only believe independent testing of full modules, not individual cells.

  2. Would it be acceptable if i chose to use Sonnen rather than sonnen? I guess they want their name to stand out and capitalising it does not do that in the German language, but here in Australia we have a different system.

    This is an interesting development (assuming the hype of the presentation is matched in reality) as it will presumably, and hopefully, instigate some serious competition to bring about a more realistic pricing structure, among other things.

    How arrogant of Sonnen to attempt railroading consumers into using their version of VPP. But they may choose this path just as we consumers may choose our path.

    Here in WA there are precious little choices when it come to electrical energy and further restricting choices probably will not work so well in our market. But why should Sonnen care? WA is a small market they can ignore. Yes, and we will ignore them.

    eePhilosopher Ronald Brakels will no doubt have interesting and insightful perspectives about this.

    ee = electrical energy

  3. Trevor Jolly says

    In re. the “3. Assume positive intention.”, I can’t help noting the lack of ‘positive’ information with which to make valid assessments. ie. PRICES of comparative products. Personally I’m a fan of quality suitable (agm/etc??) batteries-banks. I’ve had nearly 40 years of experience, and watched the technology/warranties*/etc. improve beyond measure and the prices drop almost as dramatically. AND there are no ‘conditions’ applied by the manufacture. In fact most of the hi-tech junk inherent in ‘modern’ batteries is unnecessary and only provides scope for more things to go wrong. Finally, what I’d REALLY like to see are details (photos? prices? etc) of the systems Ron and Finn/others have installed. As said previously: the real ‘value’ of this (or anything else) can only be assessed by comparison with (a) what’s available and its cost, and (b) exactly what EACH INDIVIDUAL needs. (eg an air-conditioner vs. a small desk fan.)
    * How do 12VDC deep-cycle AGM LA batteries with an unconditional 3-year warranty (expect over 5 years, properly treated) @ UNDER $2 per AH sound. (That’s a whisper over $1500 for a 10kW bank (of them) OR at the price put in TWO, balance usage between them and keep the DOD at, say, 15%. How long they last will depend on varying factors, including ‘cycling’: THAT can be pre-decided by the owner (I personally do most of what I want with a consumption of between 3&4 kWh per day, and compile my battery-bank accordingly. The GOOD news is that their IS life after death: completely worn out batteries can simply and cheaply be rejuvenated. (Not as good as new, but well worth the small effort.) A final comment re. the (often ‘required’) ancillaries: NOBODY needs inverters, chargers, etc.etc. that cost ridiculous sums when cheap little units (applied to different needs) will do the job for a small fraction of the cost. eg. a 300-Watt inverter ($125 at ‘Autocheap’) will run the lights AND a medium-sized TV in a not-too-large household. Another such will run a couple (or
    three) of computers. Reducing usage (switching off unused lights etc.) can make a HUGE difference. (I’ve long found a 2kW generator will run short-term things like microwave ovens, etc. for pennies a week) My typing finger’s getting sore, so will end here. But the options are out there. I think sharing information and ideas has a great deal more merit that haggling-over/pushing the latest gee-whiz ooh-aahs.

    • Des Scahill says

      Reply to Trevor Jolly

      Hi Trevor,

      I like your comment that “In fact most of the hi-tech junk inherent in ‘modern’ batteries is unnecessary and only provides scope for more things to go wrong.”

      The law of diminishing marginal utility is alive and well into today’s consumer orientated society.. So much so its become ridiculous at times.

      • Trevor Jolly says

        Hi Des. In the world in which I grew up EVERYTHING was hands-on and the KISS principle prevailed. I do have a high regard for modern developments in technology, medicine (at my age that matters), and many other things. But my personal line-in-the-sand lies where individual CHOICE is sacrificed to somebody else’s idea of ‘what’s good for you’. (eg electronic ‘management systems’ without which the ~over-expensive!~ product won’t work.). And that applies to basics, too. Pet hate just for the moment are ‘must-have’ ‘Anderson plugs’, which can do NOTHING that I can’t achieve with a couple of short bits of copper-pipe. Not only can one get a better connection, at ANY voltage/amperage, and very simply incorporate an appropriate fuse, but one can also save money, time and efficiency on conductors. And the kicker? Y’know what you’ve got, how to monitor it, and (when necessary) how to fix it. The idea that your battery (as opposed to a multi-battery ‘bank’) needs to be delivered/sited with a forklift, and MUST be installed by a ‘qualified expert’, and then monitored/governed remotely by some stranger/’algorithm’, strikes me as abhorrent. All the best.

  4. Warwick Duncan says

    I don’t actually give a toss about sonnen batteries but that was so delightfully written I ended up reading the entire article. Nice work Ronald!

  5. Geoff Miell says

    The sonnen Evo’s operating temperature was given as -10ºC to 50ºC.

    Is there any information on low (or high) ambient air temperatures reducing energy storage capacity and output power performance?

    Is power backup ‘seamless’/’uninterruptible’ or is there a time delay to switch over?

    • Ronald Brakels says

      Derating at higher temperatures is a definite possibility. I’d say it’s likely as we are just given it’s operating temerature without any qualifications. The switchover to backup is not seamless and sonnen says they hope it will be under one second.

  6. Michael J Keaney says

    We still seem to be stuck at around $14K for a 10 kWh battery.

    Where I live, I pay 22.5c per kWh and can export for 9.5c per kWh.

    As I have a 6kW solar plant, it is reasonable to assune I can fully charge and discharge the whole system every day of the year.

    So basically I can store $1.30 worth of my free electricity every day, for 10 years. That’s not even $5K worth of savings, how do I justify the other $9K.

    It seems that batteries have long way to go before they are going to become the renewables nirvana that is so ofter promised, or am I miising something here?

  7. Brian Crook says

    Curiosity rears its head. Is it known why the battery blackout charging requires the solar inverter to be 6 Kw or less?

    • Tim Latimer says

      Hi Brian – this limit is for solar installed on the batteries back up circuit. The reason it is 6kW is during a grid blackout the sonnen system has to manage the power output of the AC coupled inverter, as excess energy is unable to flow to the grid. The energy being produced can be used to either power the household demand and/or charge the batteries. The limit removes the risk of having too much power without anywhere for it to go.

    • Further to what Tim said, this issue applies to all AC coupled batteries that work in a blackout and support grid connected solar inverters in a blackout. As Tim said, when isolated from the grid, the battery needs to be responsible be balancing supply and demand in the home. Grid tried solar inverters are designed to just pump out as much power as there is sun, on the assumption that excess just goes to the grid. When not grid connected any more because of a blackout, the battery (which is the devices that has isolated you, and pretended to be the grid so now needs to take responsibility for the issue it created), needs to manage that excess power. When you have more solar output than household loads the battery manages this as follows :-

      1. If the battery is not full, it can absorb that extra power by charging the battery.

      2. when there is more solar power than the household needs, and the battery can absorb charging, the battery can raise the frequency slightly, which triggers a mechanism in all Australian approved grid tied solar systems where on high frequency they must either shutdown or throttle their output.

      The issue with item number 2) above is that this does not happen instantly, and takes time. So to avoid voltage spikes etc in the home etc, in the very short term we can only rely on item 1) above. So the backed up solar can’t safely exceed the capacity of the battery to charge (absorb excess power), for long enough for it to be able to signal the solar to slow down, and for the solar to actually throttle.

      So this limit, is typically dictated by the specification of the battery charger to absorb power charging the battery.

      If you have an AC coupled battery vendor, who does not specify this limit, I would have significant alarm bells ringing that they “don’t know what they don’t know” and I would not buy it until they could explain how they manage this problem.

      When Tesla started selling the PW2 here, they were not aware of this issue, and initially told people including myself that there was no limit, and they could support any size solar system. But in subsequent discussions I had with senior engineers there, they eventually realised the problem, and now they have a 7kW limit.That is the peak charging capacity of the PW2. I would assume it is likely that sonnen have a slightly lower peak charging capacity, or are being a little more conservative to help better ensure they can further reduce the risks of power spikes.

      It is not unlikely they have taken a more “conservative” approach, by the fact that they are only aiming for a switchover in the seconds range, rather than Tesla’s often sub second changeover (though this could also just be that this is a simpler and cheaper implementation). While quicker changeover is “nice”, so you have less disruptions during changeover (ie your computer does not shutdown and reboot), it is not without its challenges in terms of managing excess power. The short “break” for the sonnen, is more likely to ensure that the solar shutdown, at least for the changeover. This reduces the chances of a voltage spike if the home isolates when there is very low home loads + battery is 100% full with limited ability to absorb excess power, and solar is running 100% flat out. With the PW2s quick changeover, the solar might be still running and this could possibly cause voltage spikes if Tesla have not ensured there is enough capacity to absorb this for a short period of time (which they might have done or they might have been prepared to just live with it on the basis that it is a rare event and they think they can get away with that).

  8. Do you have any more insights to this :-

    “If a property has three-phase power, it is possible to put a sonnen Evo on each phase, but obviously, this won’t be cheap.”

    Eg :-
    1. if you install 3 batteries, 1 on each phase, does this give real 3 phase support (ie phases are all in sync and thus you can drive real 3 phase loads and things like 3 phase solar inverters).

    2. Can it support 3 phase solar inverter.

    3. Can it support single phase inverters on the 3 phases.

    AC coupled single phase batteries on all phases can be a can of worms, with a lot of gotcha’s in implementation. Particularly if they want to support solar in a blackout, as I suspect is pretty important blackout protection is one of the main reason to install a battery that in all likelihood is too expensive to ever make a payback. 1 big gotcha is the fact that for AC coupled batteries that support solar in a blackout, probably use frequency shifting to control solar output. This tends to cause lots of problems that are not easy to solve unless the system is designed from the ground up to get around these problems. For example, because if it support solar in a blackout, it likely uses frequency shifting. If it is a single phase battery, this shifting very likely happens at different rates at different times on the different phases because of different loads and generation on the different phases. If this happens and the 3 phases get out of phase, then it clearly can’t really support 3 phase loads and solar inverters. Because of this, people like Tesla only support PW2 backup on 1 phase, even though you might have a PW2 on all phases.

    There would be ways around this. For example, if the “single phase” batteries are interconnected (probably via DC), I guess there would be the possibility of shifting power between phases to solve of of these issues. ie this would allow excess power from solar to be absorbed by whatever battery has capacity and reduce the need to throttle solar on the different phases at different rates. But to date, I have not seen any AC coupled batteries that implement this.

    Also, do you know if there is any ability to charge this battery with a generator if needed in an extended blackout?

  9. Anne & Brian Crook says

    So if one has a large Endphase system, you cannot solar recharge the Sonen Evo during a blackout?

    • Ronald Brakels says

      As long as there are less than 6 kilowatts in total of Enphase microinverters on the phase the sonnen Evo is on, it will be able to charge from solar in a blackout.

    • I know nothing about this battery. But I do know a bit about AC coupling and Enphase systems. And the answer is probably a bit complicated.

      The 1 word answer is that, yes, you should be able to get the enphase solar to work in a blackout. But the implementation of this might be a lot more complicated than 1st meets the eye depending on your circumstance, so you probably should discuss this with a reputable installer with good skills in Enphase and AC coupled batteries.

      But on face value I will give you a little more detail. If you are all single phase and below 6kW, it should be trivial and no different to any other solar inverter.

      If it is single phase, and above 6kW (as it sounds like you might be), I suspect you will still be able to get it going. You might just need to get someone to reorganise you enphase strings a little so you can have 6kW on the backed up side of the battery, and the rest on the grid side. In this way the 6kW or less on the backed up side of the battery should still work in a blackout, but the rest will shutdown with the grid (which is what you want to avoid exceeding the specification of the sonnen). In fact, if you have a large enphase system, you might already have the strings broken down, and coming to multiple breakers in the switch box. If this is the case, and one of the strings is 6kW or less, it should be trivial for the sparky installing the battery to do this. If there is not 6kW or less string, it might require a little more work, but I would be confident the right installer should find the way forward for you.

      But where it gets more complicated if you have a 3 phase enphase system. But let me assure you, with the right installer, and right help you should be able to get this working with solar on 1 phase. But out of the box, it probably won’t work unless your installer gets a very specific profile that is NOT the default installed here in Australia. If your enphase system is very old with the original Envoy, you might dodge this bullet. But if it is remotely new (ie certainly anything installed after 2016), you will no doubt have the newer Envoy-S which has some extra “functionality” that you will need to work around.

      The problem with 3 Phase is to comply with AS4777.2015 rules for 3 phase micro systems which required these systems to totally shutdown if there was a loss of power on 1 phase. So the system monitors for this, and if it detects a loss of power on any phase, it shuts down. This will happen, even although this type of AC coupled battery creates its own microgrid, and keeps 1 phase up. The enphase micros on that phase can’t start for the single reason the other phases are down. But there is a workaround. You need to get your installer to install a profile which disables this feature. Once you get that, you should be able to keep the enphase inverters on the backed up phase up and running.

      But please note, that certainly when I got this sorted out some years ago, the level of knowledge about this within the installer community, and even with the people I could talk to at Enphase was not good. And i could believe it might be hard to find people that understand this issue. So there is some chance it might not be easy to find people who understand these complications. But hopefully with more AC coupled batteries out there these days, hopefully it is better understood.

      My advice to you if you want a battery, make sure your installer commits to delivering you a solution that will support solar in a blackout. And then when they have finished the install, test it yourself before you pay them.

      • Hi Matthew, is there any chance you have more details about this, specifically what profile is utilised? I am going through this exact issue now in my search for a single phase AC coupled battery to my 3 phase enphase system in Sydney

  10. Robin Memory says

    A question on charging the battery in a blackout please Ronald. (And thanks for the great article) . We have 8.5kW of solar on two arrays. Could I turn off the smaller array to leave 5kW being used only, and therefore keep charging the battery during a blackout? ( I realize that I would lose the benefit of the other 3.5kW being provided to the house). Thanks

    • Ronald Brakels says

      My understanding is that would technically work, but it may not be considered safe to have the battery configured to charge from solar if there are more than 6 kilowatts of solar inverter capacity on a phase. The warranty may not allow it.

  11. Craig Worland says

    I have today been given a quote in perth of $12,490 for the Sonnen evo.

    My issue is this battery does not seem to like working in a blackout.
    And has what appears to me to be a very poor quality inverter if its efficiency is 80 to 85%

    • Blackout Operation

      “My issue is this battery does not seem to like working in a blackout.”

      My Evo did not operate during blackout upon installation. I was aware in advance there was a software issue and that a fix would come by the end of the year.

      The fix did come on 30Dec, however it has created a new problem (and not just my unit according to Sonnen). Since then the battery has been charging and discharging from/to the grid. I export 2.5 to 3 kWh to the grid every night, and reach 0% SOC prior to sunrise, every night.

      To their credit, Sonnen are proactively working on my case (and others) whilst listening to my concerns. I have no problem with the company, but I have lost much faith in the product.

      Some interim band-aids have been tried, but so far to no avail. The Xmas shutdown has not been helpful.

      • Update. Sonnen have reverted my unit to the previous software. I did not export to grid overnight, but the blackout function is no longer working!

        • I was about to order a Sonnen Evo, I primarily want it for blackouts (and the ability to charge from solar in a blackout), I certainly don’t want to be charging the battery from the grid – kind of defeats the point!!
          It’s a bit worrying if they have yours (and others) having issues that it’s not doing what it’s supposed to and the fact that they’re saying it’s a software issue is even more concerning!
          I think I’ll hold off on any order until this issue has been resolved.

          • Has this been fixed?

            Also from Perth and recently quoted $14700 for supply and installation.
            No mention of the above problem.


    My installer says Evo not available atm due to compliance issues.
    Anyone received their battery, or confirm delay?

    • Tim Latimer says

      Hi Paul,

      Tim from sonnen here. I can confirm that we are waiting on the certification by the clean energy council. This is the final step in the certification process.

      Good news is the product is in the country and ready to go out to installations as soon as approval is complete.

      Thank you,


  13. Thanks for your response Tim.
    Hopefully before Spring!

  14. Battery Efficiency

    “I asked what the round trip efficiency was…But sonnen didn’t answer the question. ”

    I monitor my battery and many home systems with Home Assistant. Since startup on 16Dec, I have input a total of 284.2 kWh (including the 4 kWh it came with) and output 220.5 kWh to 0% SOC this morning. (see my next blog as to why it is zero %)

    That’s a round trip efficiency of 77.5%.

  15. Noise

    “Sonnen gave no information on noise output. The sonnen Evo has cooling fans, so I don’t expect it to be completely silent when they’re operating. But I do expect it to be fairly quiet. After all, there are a lot of sonnenBatteries inside homes.”

    Mine is not quiet. Installed outside and 3 rooms away, from inside it sounds like a water tap is running somewhere. Outside it is louder than my aircons. The real problem is that it generally doesn’t cycle, it runs all day till after bedtime. On NYE bedtime was 12:30 am, and it was still running then.

    However, Sonnen have advised me that a batch of cabinets (assembled in Turkey) arrived with underrated fans (x3) installed. (Supply issue and substitution perhaps?) They are running too fast and too hot, creating too much noise. Quality checking did not pick it up because when installed, the labels are hidden.

    Again, to their credit, Sonnen have finally got replacement in stock and I am expecting installation of the correct fans within a week. As to the running too long issue, there are adjustment that can be made to the cut-in thermostat temps to allow the fans to cycle correctly with internal temperature variations.

    I will update how the new fans go after install.

    • Ronald Brakels says

      Sorry to hear about the problem, but I am glad to hear Sonnen are getting around to fixing it. I definitely will be interested to hear how it goes.

    • I’m in the process of getting an Evo installed and reading about it having these problems is a bit alarming. It’s being installed to be able to charge from solar in a blackout situation. If what you say is true then the firmware issue is quite dissapointing and this really leaves a bad taste.

      And being assembled in Turkey!! What the?? They are supposed to be assembled in Wildpoldsried, Germany. The Sonnen website states this specifically. This makes it feel like a bait and switch routine.

      How do you check to see where it was manufactured and where it was assembled?

      I’m really hoping that this isn’t a common issue.

      To Ronald, have you heard any other reports of this kind? Whirlpool forums don’t have much on the Evo and I couldn’t see any mention of issues.

      I’ll check some solar Facebook pages but I’ve only seen positive comments so far.

      This report really takes the shine off

  16. My comments became scattered because I replied to individual posts. In summary, I have the following issues.

    Blackout feature not working initially; a software ‘fix’ caused unscheduled charge/discharge from the grid, so software was reverted to original and blackout feature now fails.

    Fan operation noisy and running almost constantly, blamed on wrong fans being fitted. Replacement fans were identical so Sonnen now scratching their heads as to why inventory tracking indicated mine were the wrong ones, and now they are unsure which other units have the wrong ones. The ambient thermostat was set too low and has now been adjusted to 35°. Since then, first hot day was yesterday and the fans only operated when ambient was above 35° but they don’t react to internal temps up to 82°. Still noisy.

    I have measured capacity at 9.31kWh, well below the advertised 10kWh.

    I have measured Round Trip Efficiency at 78%, less than desired/expected.

    New issue is ‘Ramp Rate’, both up and down, of ~14W/s. The other day I had production 8kW, charging 5kW, consumption 1kW, and 2kW feed-in. Then a cloud came over and production dropped instantly to 2kW. But my battery needs to ‘ramp down’, and it doesn’t react quickly. So initial parameters were production 2kW, consumption 1kW and charging 5kW. The extra 4kW imports from the grid! Eventually the system will reach net zero on the grid; production 2kW, consumption 1kW and charging 1kW. BUT, at only 14 W/s the battery takes ~5 minutes to ‘ramp’ from 5 to 1, importing from the grid this whole time. This happens in reverse too, say boiling a kettle at night and drawing from the battery. When the kettle boils, and consumption suddenly reduces, the battery continues to discharge to the grid until it slowly ‘ramps’ to the new steady state. In fact, every time ‘net zero’ to the grid is disturbed, the battery charges/discharges to/from the grid.
    Sonnen (AU) have been excellent, but their product is not. They asked me to give them until Monday. Hmmm.

    • I must also add, I have had 3 events involving large discharge rates. The latest was just yesterday when the battery, already at 100%, began discharging at 7.4kW. Concerning is not only that it was in excess of specification, but that there was no ‘ramp up’, the change was instantaneous.

      That discharge went straight to grid because I was producing excess at the time.

      It then took 7 minutes or so to return to steady state, and in that time I had exported 5% of capacity. This stuff is very visible to Sonnen, and they are truly going out of the way to find both the cause, and a solution, but I am not confident they can….by Monday.

      They have entertained all possibilities for me so far including return of the product

  17. Hi Batts – thanks for the detailed explanation but this is not how I thought it worked. I provided this and the install company said Yes:
    In simplified terms, is this how it works?
    1. Solar power powers the home
    2. Spare solar power charges the battery
    3. When the battery is ‘full’, spare power goes to the grid
    4. When there is no sun, battery powers the home
    5. When battery is ‘fully’ discharged, grid powers the home
    At no point did I think that the battery would charge from the grid or discharge to the grid. Thanks

    • Yes @Trevor G that is correct. Mine is behaving badly.

      There are only two scenarios when battery should interact with the grid.
      1. Time of use mode – useful for charging using off peak tariffs.
      2. Changing the backup buffer higher than the current SOC.



    Well it’s D-day tomorrow so I thought I would test the battery and examine its performance since I last spoke with Sonnen Australia.

    I am pleased to report positively.

    Blackout function: I tested this today and it works! Ran off grid for about half an hour, loaded up to about 4kW, the inverter on the same phase came on line and was producing to offset consumption. The only remaining issue is that during off grid operation, neither Sonnen or Solar Edge inverter data is available, other than battery SOC. This might be an install issue, but still to be investigated.

    Fans: Its still only come on on the one day ambient was above 35°. I have questions to ask about the other temperature sensors and expected fan integration.

    Ramp Rate: like magic, this has been resolved. The battery now stabilises within 4-6 seconds to large changes of charge/discharge demand. 14W/s has become at least 500 W/s, so no longer a significant factor.

    I also have unanswered concerns re the battery capacity and round trip efficiency, and the cause of the over-spec random discharge rates, and whether these issues are systemic or just in my system.

  19. I finally got my Evo installed today and too early to say much.

    The fans have been going the entire time since commissioning though and it is a warm day here at my place in Brisbane. My weather station is saying its 35C with a feels like of 42.7C. So I will see how it goes over night as it cools down.

    I got the app logged in to see what was happening and the numbers are matching the ones generated by my other monitoring in place.

    The adventure continues.

    • Tim, if you type in the ip address you can log in to a different dashboard with more information than the app. The initial ‘User’ pw is on the label on the battery.

      Did the fans turn off?

      • The fans have been going flat out since commissioning. It’s definitely not quiet and much louder than our larger split system air conditioner. The ambient temp has been down to 21C.
        My installer said they haven’t come across this issue before.
        I had a conversation with Sonnen about it on Friday and they are going to get back to me on Monday hopefully.

        Checked out the dashboard, and can see the extra settings that aren’t visible in the app.

        Firmware version
        Software version 1.8.7

  20. Sonnen have become a little bit shy with me and my installer. I think my experience has raised questions they cannot or will not answer.

    Good luck to all the new owners, but mine is going back.

  21. We’ve just had an Evo installed in Perth, so thought I’d add my 2 cents.

    We ordered December 6th and were advised stock was available. Turned out not to be the case so it was finally installed on 24th of Feb.

    Installer did a good job. Neat and tidy including adding an extension to our panel to house the power meter, Solar analytics unit and bypass switch. Happy with all that.

    Less happy with a few other things. After installation, the battery does a 24 hour self test and set up. After that ours just switched to fault condition and won’t charge. Monitoring reads the house consumption to be exactly the same as the generation – obviously not correct as we are exporting all day.

    Had the installer back in to do a physical double check and then passed to Sonnen support who initially said “looks fine from our end” and then “someone will come look asap” but with no ETA. It’s been a week now and still currently no idea when someone can come look at it. Will update once we learn more.

    A few people asked about noise. I can say it’s loud. Very. Sounds like an industrial fridge when it’s on. For reference, we have a fronius primo in the same space and I don’t think that’s loud at all. The Evo can be heard over our car running.

    Anyway, that’s our story so far. Happy to update with how it works in practice, once it works.

    • 1 month update.
      Well, we are a.month later and still waiting for someone to come out. We have been advised by email that we will need to have both batteries replaced. No one has been out to inspect in person though. Last communication a few days ago said batteries have been shipped but waiting for them to get to WA.

      Other than that, our solar analytics is still not working although I finally got a reply to the ticket after 2 weeks. We are also losing between 10 and 20% of our export capacity at the sunniest part of the day due to over voltage. Our 5kw fronius now averages about 4.3kw unless we are drawing a lot of load locally. Hopefully this is temporary and due to the malfunctioning battery. Will know when it finally charges.

      Will post again when there is some update.

      • My Sonnen Evo is being replaced this week with a Powerwall 2. The original installer is doing the job and has been most helpful, however the installer reports a diminishing relationship with Sonnen.

        The Evo has been functioning okay since my decision was made to return it, however it still suffers from sub-80% efficiency, usable capacity of only 9.2kWh, and several seconds of reaction time or slow ramp rate. Measured internal temperature consistently reaches 83 degrees before charge rate is reduced and/or cooling fan operates

        • I really hope it doesn’t come to that for us. We picked the Sonnen as we we wanted the long term backup capability – as in it can keep charging while the grid is out. The installers who would quote here for a Powerwall told us you couldn’t do that with one, regardless of what Teslas own site information says.

          Fingers crossed, we got a call earlier today saying the battery modules are in Perth now. Shall see how it plays out over the next few days.

          • About 6 posts above this one I pointed to the Whirlpool forum.


            There, someone has written, “The Powerwall islands one of our 5 kW solar inverters with 7.2 kW of panels connected to that and so charges the Powerwall on a daily basis when we have an extended outage – so could go on indefinitely in backup mode.”

          • I am as confused about this as you are. I even sent a link to our original installer for testla’s documentation on how to run off grid but just got “not possible” as a response but with no explanation why. When the next installer I spoke too said the same thing I kind of gave up.

            It’s apparently out there and exists but Perth says it doesn’t.

            Oh and the first installer doesn’t supply Sonnen gear so he wasn’t trying to push us to that. It’s all very odd.

      • Quick update. Good news and bad news.

        The good news is I got a call from the contractor that Sonnen is using in Perth to book a time for them to replace our modules.

        The bad news is the earliest date they can do it is 3 weeks away. So a full 2 months after original install.

        Here’s hoping it starts up after this.

    • Bonus update.
      After our installer went into bat for us again, Sonnen chased up their service contractor and got our module replacement brought forward.
      The service tech replaced our modules, and checked the fans. Turns out our fans are ok but the thermostat is broken. They will be back to replace that later.

      End result of the new battery modules is unfortunately no change. Still no charging and after a day the unit is back to showing red status and “contact service” message. Next step is apparently a new inverter although waiting for a response from.sonnen again.

      Will keep you posted as we hear more.

    • Not sure if anyone is still following this but thought I’d update again. Last advice from Sonnen was new parts would be at service contractor 21st of April.

      As far as I know they were but it took 2 more weeks of chasing to get the service contractor to confirm receipt and then they advise earliest they can come to install is June 1st.

      So as of next week we will be three months since install without it working at all.

      If anything new happens I’ll follow it up here.

  22. Trevor Gross says

    Thanks James C & Batts for your honest feedback – So glad I waited to make a decision on the Sonnen Evo. Going to wait a few months before researching again.

    • Happy to share as I couldn’t find a lot of direct experience being shared when I was researching.

      However it ends up, I will post a follow up.

      Still hoping they can actually make it work.

  23. Part 1

    I thought I’d put my experience with my Evo in as some added info for whoever might have one or get one.

    Mine was installed in early February. It’s had issues with the fans running all the time. Sonnen sent a tech out and we got a partial fix for that by adjusting the thermostat to kick in at 35C. That’s mostly stopped the fan running 24/7. When it’s hot it needs to run the fan but they don’t turn off again sometimes when everything cools down. It seems to change the next day after the battery has got to zero SOC. And it stays off until heats up and off in the evenings. Which is better than it was. So a permanent fix for that is still to be found.

    I’ve waited to get a few months of data to determine the battery efficiency. The highest daily efficiency I’ve seen was around 92% and the lowest was around 66%. The average is sitting at around 82%. That’s taken from the data you can download from the Sonnen portal.
    So not sure what to make of that yet but that covers sunny and rainy weather periods.

    The best day had since installation we drew about 200wh from the grid. I’ve also got a SMA home manager 2 that correlates the data. And I cross reference that against the data from AGL for my consumption. So I’m confident the metering is correct.

    Being a small battery at 10kwh we get more out of it during the day than it’s stated storage amount as we do all our heavy consumption use during the day. Dishwasher, use air con and such. So the battery supplies while they are clouds etc. So there has been days it’s discharged over 15kwh into the house. It definitely charges and discharges at 5kw no worries.

  24. Part 2

    It does seem to have a second or two lag in reacting to power draw changes. Not sure if real or a polling interval thing though. My home manager is the same. So its ‘real time’ data is not displayed instaneously. The Evo doesn’t like my ceramic hot plates though and definitely doesn’t react fast enough to stop them from drawing from the grid. So that could indicate the Evo not being fast enough to react. We still draw from the grid even with lots of battery capacity available. 8w here, 40w there, it fluctuates. Adds up to watt hours a day but still that could also indicate the slow to react to power draw change issue.

    I’m following that up with Sonnen. I’d like it to react faster.

    I’ve got mine wired for backup on a 5Kw solar inverter. The backup hasn’t worked 100% of the time. When I’ve tested, it flicks over to backup in about half a second. Lights go off lights go on kinda like blinking. But it is spasmodic in actually going to backup. I’ve haven’t extensively tested but it seems to work if SOC is 100%. But it doesn’t always flip over to backup at SOC < 100%
    Again Sonnen are aware and supposedly a firmware fix is coming.

    Other than that it's doing what I expected. I'm talking with Sonnen and they are doing things, albeit slowly. I have confidence they will get these issues sorted. They're a big company going nowhere and it's a new product still.

    Find me any battery they didn't have teething issues? Whirlpool is full of threads about issues people have had or are having with other 'big name' batteries too.

    • Hi Tim, I truly hope Sonnen resolve your remaining problems, and that they are just teething issues.
      Your fan experience is the same as mine. If you monitor ‘tmax’ you may discover very high measured temperatures with no fan operation, I never understood this.
      Reaction time was always an issue for me, and the system constantly drew small amounts of energy from the grid as a result. My Powerwall replacement was installed 2 days ago, it draws zero from the grid so far.
      To properly measure daily efficiency, you need to compare power discharged overnight, with power to recharge to 100% the next day. I set up home assistant monitoring to measure these parameters between 2pm through to 2pm, not midnight to midnight. This approximates what I want to compare but is invalid on days when the charge cycle is slow or when cloud interrupts the charge discharge cycle. The only complete measure of efficiency is the lifetime figures, but you need to factor in that the battery probably came with 40% SOC, so you need to add this to the input side of your equation. That will drop you 82% figure slightly. The other thing you could do is calculate efficiency when the SOC is at the same figure as on install. You should be able to see your startup SOC on the portal.
      You infer the battery capacity exceeds spec. You may see you get more than 10kWh on a given day, but that’s only because during the day it keeps topping up. It smooths the highs and lows of solar production which is great, but you will discover, sadly, that the actual capacity is only 9.2kWh.

    • Thanks for adding your experiences here Tim. Really hoping that some firmware updates can make these kind of issues go away. It should be possible at least.

      For now – I would just like to be able to turn our unit on – but time will tell.

      • I saw your update James and sorry to hear that its dragging on for 3 months. I was lucky that the installer I have is responsive to the issues I was having and were talking to Sonnen for me also.

        GI Energy were very good in getting things sorted out for me.

        I can report that the firmware update has fixed the back-up working intermittently. It now works consistently and kicks in nearly instantaneously. I have my PC’s on a UPS though. The changeover time is blink and you’ll miss it.

        The fan issue is sorted and everything is working as advertised.

        The only thing is the time it takes to react to changes in power consumption. We still use about 400 – 600 watt hours a day when good sunny days and full battery charge.

        For the last 30 days we are at 95% self-sufficiency.

      • James, you remain very patient. Perhaps it really is time to push for a DOA-based full refund?

        My money has been much better spent on my replacement Powerwall. Its [proven] capacity is 15kWh, much better than spec, and superior to Evo’s 9.2kWh. It’s running at 90% efficiency despite it appearing to consume about 100w when idling. There is zero fan noise, and reaction time is only costing about 180Wh per day. Much better value, IMHO. I have not been able to fault it in any respect. In terms of future-proofing, I can piggyback a second battery in a smaller footprint than the single Evo.

        Once again, good luck with yours.

  25. No feed back anyone? All problems resolved or not? Just curious.

    FWIW, I have installed a 2nd PW2. Consuming about 250Wh per day in “running costs”. 87.5% efficiency. 29.9kWh capacity. @nd battery was $5k cheaper than the first due to price reductions and a recent rebate offer.

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