Last week, my Powerwall 2 turned seven.
To celebrate, I stumped up $10 for a 1-month subscription to the excellent, third-party, NetZero Powerwall monitoring app and ran some diagnostics.
The results: just 6.4% degradation after seven years, averaging 0.7 cycles per day. I reckon that’s excellent.
If you’ve got an ageing Powerwall and the NetZero app, I’d love to hear your degradation numbers – post them in the comments. Let’s build a library of long-term real-life experiences.
Not Even Halfway Through Warranty
I’m also part of Tesla’s VPP, which (although winding up) came with a nice sign-up bonus: a warranty extension from 10 years to 15. I’m not even halfway through the warranty period – yay!
Honestly, if a meteorite flattened my battery tomorrow and I had to buy another, I’d go Tesla again. Two reasons:
1. Proven quality over time
Most battery hardware on the market looks solid when it’s new. But the truth shows in the long term. In that sense, my Powerwall 2 is performing far better than I expected.
Granted, you can’t buy a Powerwall 2 anymore, and the Powerwall 3 uses a different chemistry, but Tesla has earned confidence in its manufacturing quality and warranty support.
2. The app
Once the white boxes are on the wall, you’ll likely never physically interact with them again. The app is where almost all the product experience lies. It’s the interface between you and your energy system, the thing you check weekly, daily, or obsessively throughout the day. It’s what you must configure when you change electricity tariffs, need to change backup settings, or ensure your EV is not gonna guzzle expensive peak grid electricity.
The Tesla Powerwall app is, bluntly, a nine-and-a-half out of ten. Intuitive to configure, so the battery control software can get on with minimising your bills, while the interface is clear, responsive, and beautiful. It makes sense of what’s happening in your home at a glance. It shows solar generation, household load, battery state, and – if you have a Tesla car – EV charging in one tidy view.
Compare that to many other brands. Yes, they’ll have all that data, and if you look hard enough, you’ll find plenty of configuration settings, but the app feels like a teenager made it in their bedroom between Fortnite sessions.
The Tesla Powerwall app provides a terrific user experience.
Does Your Solar Company Take Their App Seriously?
Two stupidly simple User Experience (UX) tests will tell you if your solar company takes their app seriously:
- Do you keep getting logged out? With cheaper brands, you are constantly being prompted to log in. With Tesla, I can’t remember the last time.
- Does it take you straight to what matters? Tesla opens with my home’s status. Badly designed solar apps make me pick a solar system (or ‘plant’) every time. Ridiculous when most people only have one energy system in their home. Even if you do own multiple solar systems – let the user choose a default one to display!
Tesla even lets me put a widget on my home screen and my watch.
Small Details Matter
These are small details, but they make the difference between an app you use daily and one you avoid. And if you avoid the app, you’re not getting all the benefits of having a smart energy system in the first place. It goes without saying that if they can’t get these two things right, there’s no hope that they’ll make configuring your system for max savings intuitive. So you won’t, and that will cost you $$$.
So, seven years in, I’m still firmly in the Tesla camp. The hardware has stood the test of time, and the app is still miles ahead. If you’ve got a non-Tesla system with an app you actually enjoy using, I want to hear about it in the comments – because for me, the app is the product.
Phase Shift is a weekly opinion column by SolarQuotes founder Finn Peacock. Subscribe to SolarQuotes’ free newsletter to get it emailed to your inbox each week along with our other home electrification coverage.
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Ours is 7.5 years old, and have similar numbers to you
Capacity: 12.68kWh
Degradation: 6.07%
Energy Charged: 26,847kWh
Energy Discharged: 23,385kWh
These figures came from Home Assistant, so i dont need to buy a subscription and can graph over time.
We are based in Melbourne
Huh, you’re praising pretty basic functionality. My NeoVolt app (and webapp) clearly shows my house load, solar, battery state, charge. discharge etc. If I had an EV it would show that too. And I never have to re-logon to it.
Nice selection of historical data and diagrams too, which can be exported for further analysis.
Meanwhile on the Amber groups, I’m seeing endless issues with Tesla and VPP integration.
I’m in most of the Amber groups and haven’t seen any of your so-called “endless issues” with Tesla and VPP integration at all.
The most common issues that I’m seeing are with Sigenergy, particularly with their export limits not funconitionly correctly for those on FE with SAPN.
An interesting post, Finn. Particularly your last comment.
“……because for me, the app is the product”.
I suggest that the most important part of that statement is the first bit. Because you are an energy needs, I think your needs and interests are different to the great majority of solar energy and battery purchasers.
I for one, a keen supporter of renewable energy, have an absolutely different point of view. As does almost everyone I know. I would probably look at the app a number of times after my next system is installed and then rarely after that to check the system is working properly. Some of my friends would probably never even use it. To most people the product they purchase would be the panels, inverter and battery or perhaps even more likely the electricity bills they don’t pay.
Perhaps the more important questions are “Do you use the app? Regularly? What does it do for you? Do you care?” Even those answers would be biased on this this site of enthusiasts.
https://protonsforbreakfast.wordpress.com/2025/01/10/powerwall-battery-degradation-winter4/
I have been monitoring my Powerwall 2 for 4 years now. And although I love the product – and I don’t believe there’s anything better out there – I am sceptical about these low degradation figures.
I measure battery capacity each winter by waiting for days in which the Powerwall fully discharges from 100% to 0% (self-indicated) with little or no solar re-charge. In the UK we have many such days but perhaps in Australia this never happens!?
I find degradation of 0.4 kW/year or about 3% per year.
I still love the product and suspect that all competing products from a similar era are worse. But that’s what I measure.
Best wishes
Michael de Podesta
P.S. Thanks for the blog
I find the Fronius app is well laid out and easy to use.
Shows me everything I need to know.
Yeah, I agree to a point. But have to side with Finn re the Tesla app. I used Fronius app exclusively from 2017 to 2021. Still use it occasionally, but got my Powerwall in 2021 and rely on that for daily system (re)configuration to maximise solar car charging – because I don’t have a WiFi enabled charger.
Yes indeed, the app is the product. Unfortunately I only have a “dumb” phone, so my decision will be based on whether it has a browser-based control panel that I can use from my laptop. Or is this concept going the way of the dinosaur?
My Fronius setup still allows me to
Log in via the browser to change more advanced settings like setting charge times etc.
I don’t see the browser view going away.
Hi Finn,
Thank you and your team for your excellent blog and web resources.
I have the Huawei Fusion App which shows me similar data.
I find it easy to use.I dont have an EV or a home battery yet..
Its about 5 minutes behind.
Its great to see where, when and how much energy we are using, and where its coming from.
On another subject, I need to automate three or four largish ( 3 to 6KW) floor heating loads and one airconditioner plus a car charger and home battery when I purchase these. The hotwater is heated with a heat pump (850W) on a timer.
I’ve enquired about Catch Solar Control relay but it aparently can only control one load even though it has six channels.Not sure how the Monacle App would work using multiple Catch Control relays. Do you have any suggestions of how I can maximise self consumption and minimise grid energy consumption, with automation?
Regards Phil
My Bluetti AC300 is now 3 years old and their app has improved over that time. I do tend to spend a lot of time using it.
It gives me all I want on one screen. SOC, PV, Grid (imports) and any DC or AC load. (No EV here yet, but it would not have the ability to monitor that).
Tapping on the SOC gives SOC for each of the modules and the current state of the BMS of each.
It has a total lifetime PV generation and CO2 saved estimate and $ saved total on the main screen. It also has historical data.
They have a grid connect model now and I expect the app for that might have more features.
There was a bad batch of PW2s from ~ 2019 that have been causing owners much grief. Tesla thankfully have been honouring warranty as they have lost 30%+ capacity since installation.
As to the app, boy you are easily pleased. Seems rather limited and restrictive to me, and the feature set seems to be getting reduced over time.
My new Sofar system works with the Solarman Smart monitoring system for phone or PC. I have it set up on my PC.
This is a decent display and easy to see what is going on but has little or no control over anything.
To make any adjustments to how the system is operating you need to use the buttons on the inverter. This is easy though because the inverter has nice LED displays plus a decent sized LCD screen like a phone.
Apps are funny things. They always seem to miss something you want, but provide other stuff that you never realised you were missing.
Everybody has their views of course, but I like the Tesla app for some things. Was playing with it a few weeks ago:
Round trip efficiency = 88% (not brilliant, but similar to Finn’s)
Age of battery based on usage = 3.7 years (equivalent of 1180 cycles).
Physical age is 4.5 years (installed 2021), so looks like will easily outlast 10 year warranty period.
Haven’t figured how to get capacity figures yet, so can’t judge degradation.
Fronius app is helpful for costing info and has excellent reporting functionality. Which is good for lazy people like me who only want to examine minutiae every few years. Or when I get fed up with current energy provider.
Whoops. Just realised PW2 is 3.5 years old, not 4.5. So is actually about right for both physical and usage age.
“Once the white boxes are on the wall, you’ll likely never physically interact with them again.”
Would have agreed a week ago but…..
My nearly 5-year old PW2 died a couple of days ago. Some interesting info from app:
Stopped working @ 11:30 AM on 26 August.
Discharged battery to (indicated) 0% @ 11:47 AM.
BUT CONTINUED TO DISCHARGE AT 0.3kW/HOUR UNTIL 9:25 PM.
So that suggests it still had 3kWh available when App first showed 0%. The app warns you about erratic behaviour below 5% charge so not sure what to make of how it behaves below 0%.
I noticed problem at about midday on 26 August and contacted supplier (Stag Electrical) immediately. Received acknowledgment. Next morning app said “one or more Powerwalls are disabled due to an internal fault that requires replacement. Contact your supplier to schedule service”. Updated supplier with that message.
Few weeks ago I gave supplier 1star review. Still waiting for response to service request ……
Hi Tony
I that’s where the fun begins. When things go wrong. I think that Finn’s statement about warranty support by Tesla is a joke.
Finn helped me when my Powerwall 2 died from a lightning strike on our property (no other electrical damage) – Tesla after Finn’s VLOG replaced the unit.
I had concerns with the installation method (we had an underground coms cable to the gateway battery- designed by the installer – organized by Tesla) the 18mths later lightning 1.5kilometers from house – and the Powerwall died again. This time Tesla wiped their hands from it and didn’t even want to investigate the how and why’s.
My advice stay away from Tesla as far as you can, otherwise you will discover they don’t care about customer support. Some we’ve got a $13k white useless box on the wall of the house that they could even be bothered to recycle.
Stay away from companies that don’t want to even talk to former customers
Hi Dave,
Had similar problem with my SolarEdge system. We’re on a rural property and because of system config. backup unit and inverter have 50m comms link connecting them. I asked the installer if the link should have surge protection but he said no. Previously I’ve had problems with long comms links being fried in electrical storms.
Last Jan we had electrical storm and system partly died. No app monitoring, but kept producing. I called supplier who called SE. Told supplier I suspected comms link that wasn’t surge protected.
After a month of no response, I got letter from SE saying because of “lightning strike” (it wasn’t a strike, just remote electrical storm) my whole SE system would no longer be covered by warranty!
Eventually, with help from Solar Quotes, and threat to take the matter to NSW Fair Trading, SE agreed to come look at my system. And what did they find? The comms link was fried. They replaced that and system is working again.
But took 3 months to fix.
Glad to hear your Powerwall is performing well Finn.
I have just installed a Sigenergy system (inverter, battery, DC charger & gateway) and so far couldn’t be happier with it. I agree with you, for me the app is the most important part of the system and I would rate the Sigen app (at least) 9.5 out of ten, much better than I was expecting. It’s early days yet so will have to wait and see how things go in terms of long term performance, but the whole Sigen system seems very well designed and integrated with the user in mind.
I previously had a Solar Edge system which generally performed well but their app isn’t as user friendly as the Sigenergy one. And don’t ask me about SolarEdge support!
Same enthusiasm for the mySigen app here! Of course, there is no such thing as a 7 year old one to compare on that front. But one thing that would make me not opt for Tesla (apart from the musky one) as an alternative is the size through stackability that Sig gives. With 4×8 for 32kWh, I couldn’t imagine playing with a measly 13.5kWh.
Ditto here re SolarEdge inverter, added AC-coupled to new Sigenergy system, very happy with it.
Ditto re SolarEdge support – software support non-existent, but hardware support excellent (i had prompt replacement under warranty).
Sigenergy app is great, and they listen – i requested an ability to charge battery on request, and it appeared in the app pretty promptly.
That said, i write my own interfaces to integrate with home mgmt, and whereas SolarEdge API was cloud-only and has withered and no longer accessible, Sigenergy API is excellent with choice of direct access (which i use to bypass internet) or via cloud.
Power outage here from Fri night to Sun night, and a new power outage since this morning [storms], the home battery is sitting on 49% and whole house running fine
Just been following the Netzero instructions for connecting to the Powerwall Gateway for diagnostics. But I cannot find a password sticker inside the Gateway door or in the (paper) Powerwall user manual.
There is a sticker with a part number (TPN) and serial number (TSN) but neither works as a password (last 5 digits according to
https://docs.netzero.energy/docs/diagnostics/Powerwall2 )
Looks like I will have to contact my installer (Solarpro) for this information.
I was using the iPhone Netzero app as the Mac app is not able to run diagnostics.
I will post the diagnostics when I get Netzero working. It will be interesting because I now have two PW2 – one installed in 2018 and the other last month.
Where did you get the 2nd Powerwall 2 from? I have been wanting to add another to my first but only now can afford to do so.
Considering selling the PW2 and putting in a different brand of more capacity for better value.
I considered a Powerwall 3 for my new battery installation but it lacked the flexibility of modular systems.
I eventually settled on a Sofar system because the inverter can have from one to six 5kWh batteries attached to it.
Your second option might be best. In June I was contacted by my original installer who had obtained some stock of PW2. There was a small window for installation from 1st July (Federal Rebate started) and, I understand, 1st August when the superseded PW2 would be no longer eligible for credits. Mine was installed on time and the rebate arrived in the bank in late July.
So far the expanded system is going well. Sometimes I manually charge them (via the updated Tesla app) during off-peak times when I know there will be several overcast days and they easily power the house during peak times.
Finn, for this old-timer, Victron monitoring & control is ideal. The touchscreen controller in the workshop between kitchen & garage can be tapped on the way past, with off-grid frequency flagging capacity excess for usage decisions.
Sitting in the sofa, a click on the PC duplicates the interface in my browser – no need to put down the coffee cup. (The GUImods package update gives individual string yields second-by-second on a mouseclick.)
Histograms of hourly yield, consumption, SoC, AC voltage & frequency, & string yields back to dot require a cloud login. I can see when visitors in the old house are up & making breakfast.
The MG4 auto-starts charging on plug-in, but the Victron phone app is great for checking progress from the sofa, and manual stop. I now disregard “Surplus Solar Only” charging, just dumping 7.2 kW, with the 46 kWh house battery filling cloud gaps. The 3 banks have an average cycle count of only 61 after 1.5 years, anyway. (The Jikong BMS phone app is great.)
Yes Eric,
The Victron app is hard to beat for sheer number of parameters you can check.
Possibly too nerdy for the average foot fan though.
They even have sensors for water tank levels (important in a boat)
Do you have any screen shots of the EV app?
I know the “charge on solar” function simply didn’t work when they released it, but was led to believe a few software updates later it was working?
Cheers
ah, so I’ll ask the question – if the Tesla app is so good, why did ya need to subscribe to a 3rd party app for 10 bucks a month!
Has sophisticated automations for many scenarios & use applications; also string info; also brilliant OCCP ev charging for non Tesla EVs & chargers. Great app.
The PW3 by itself has been excellent & the AI usually takes care of things well. Netzero provides a more prosumer interface for those who want it.
Have been using those two for 12 months now & the combo is excellent, plus the Netzero support, development & execution of new features. For my Mach-E & Wallbox, this has been fantastic.
The Tesla app is good as long as you don’t want to do “fancy” stuff like do a bit of extra charging early hours of the morning at off peak rate while also running in time based mode and doing primary charging from the grid during shoulder rate period.
Netzero also does other stuff that the Tesla app doesn’t offer…like notifying when firmware updates are pushed to the system and degradation status of the battery.
The latest versions of the Tesla app/gateway firmware have been jigged so that battery delays charging from the grid for an hour or two during shoulder tariff period to “optimize” performance of the system. On grey days I frequently get to 3pm and the battery isn’t fully charged.
My overall assessment of my PW2…..good when it’s working but response by Tesla to support requests have been abysmal.
I’m a fan too but Tesla batteries actually start life at over 14 kWh capacity. Measuring degradation against 13.5 kWh nominal capacity is a bit disingenuous.
Exactly, I’ve still got the pdf brochure from when mine was installed- useable capacity 13.5kWh and full capacity of 14.0kWh.
Does the Tesla Powerwall expose attributes and controls to third-party apps such as Home Assistant to allow for automated forced charging and other things?
I love my PW2 as well, but would disagree with the comment that the app is “a nine-and-a-half out of ten” and “Intuitive to configure”. The app does not actually provide any means to configure when to start or stop charging of the battery. The best one can do is to put the PW in TBC mode and played with the import/export $ rates, and hope and pray that the Tesla AI would operate the PW in the way you want. There is no way to tell the PW to start charging at full speed at a particular time to take advantage of free or even negative grid rates, e.g. The capability is there, as that’s how VPP works. It is just not available in the app to the end user.
As I mention above, the “Storm Watch” function now has a feature to manually start charging for a user-selected number of hours. However this starts charging immediately and cannot repeat (eg each day).
I have put in a request to Tesla to add a start time option … maybe we will see it next year.
BTW this manual charging “advanced” feature needs an iPhone to be paired to the PW.
Let’s not forget — Tesla isn’t even a battery manufacturer. Powerwalls use Panasonic/CATL cells assembled in Nevada, wrapped in branding and a slick app. Just because you pay more doesn’t make the product better. I’ve had great results with Growatt — same proven chemistry, solid app, and far better value for Aussie households. And being impressed by 6–7% degradation over 7 years? That’s completely typical today across brands. Guarantees only set a conservative bar (30% in 10 years for legal cover), but in reality these batteries all last much longer.
Hi Finn,
Great article – very interesting!
Curiously, my 7.5 PW2 has had zero degradation since installation!
Current capacity is 14,083 Wh from a rated capacity of 13,500Wh.
Gotta be happy with that.
Info also taken from NetZero app
Hi
I have an alphaESS system – I don’t think I have seen anyone else mention them. – 7KW panels, 5KW inverter and 10.1KW 96V battery. The app, which I run on my PC and Android phone is excellent in terms of provided info and ease of use. It’s always awake – no need to log in. The system is fairly new – about 6 months old and I look at it very often – the novelty hasn’t worn off yet. Also as a retired electronic engineering person I have more than an average interest. Not sure about configuration capabilities as I have not wanted or needed to change anything so far. The only comment I would have on batteries at this stage is 10KWH is not big enough and doesn’t always carry my aircon etc load through the night – especially in winter. Thinking of adding another module – especially now the subsidy is there.
Hi Rob,
As always, we recommend people check the one star reviews because cheap inverters attract cheap installers who don’t offer great support.
Leave your own reviews if you have some insight to share.
Cheers
Finally got the Netzero app to “connect” to my Gateway. I thought it was a Gateway 2 but a very helpful person from Tesla Support advised me it was a Gateway 1. This meant I had to configure a “legacy” password in accordance with the Netzero online instructions (downloading the Tesla One app, temporarily joining the Gateway wifi with my iphone and setting a new password…)
The diagnostics reports:
1. Powerwall 2 built 2018, lifetime discharge 18,954kWh
Degradation: 5.4% (capacity now 12,771 Wh) – pretty impressive for 7 years of service
2. Powerwall 2 built 2024 (installed July25), lifetime discharge 400kWh
Degradation: 0% (capacity now 14,478 Wh – rated capacity 13,500 Wh!)
So.. I think there is a little fudge factor in the degradation value – the battery starts with a capacity greater than the rated capacity.
It seems that the “balance” issue with dual Lion caravan batteries – where they must be the same model and should be approximately the same age – does not apply to Powerwalls
I’m fighting Telsa to get my Powerwall 2 replaced under Australian Consumer Law- due to the poor quality. Finn’s is a classic example only losing 6.4% at sevens years old. I’m sitting at 24% degradation at 5 years old and Tesla refuse to comply with Australian Consumer Law and replace it- due to it not being of acceptable quality.
Tesla can generate a graph of the degradation over time- they sent me a graph back to 2023 that showed it had already lost over 2kWh capacity. So I requested a graph from installation be provided (to prove it actually start with 14.0kWh total and 13.5kWh useable capacity.) It was at that point my Emails were ignored. IMHO Tesla have something to hide- proven by them not supplying that graph.
I’ve lodged a complaint with the state business/ consumer affairs, and with the ACCC. I’m locked out of my Gateway 2, so can’t check the degradation myself – Tesla are the only ones who can reset the password. They’ve disable the old methods to reset it yourself. Dodgy