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Tip/Warning if you have more than one Powerwall

Yonki

Member
Supporting Member
Mar 31, 2015
601
1,771
Pacific Grove, CA
Just had a Solar + 3 Powerwall system installed. Have been running off-grid while waiting for PTO. App shows 3 Powerwalls with a state of charge somewhere between 0% and 100%. Walls charge up to 100% during the day; house runs off Powerwalls when there’s no solar production.

After a week or two I got the feeling that the Powerwalls were discharging too quickly. As an example with nice round numbers, let’s say I was running off the Powerwalls for 13.5 hours between sunset and sunrise, and my house used an average of 1kW. So I would have drawn about 13.5kWh from the Powerwalls between when the panels stopped producing and when they restarted.

Since each Powerwall has 13.5kWh of energy, I basically used 1 Powerwall worth of energy overnight. But my app said I was at 50%, not 67% (as you’d expect with 3 Powerwalls). I did similar measurements and calculations over several days and concluded that my system was behaving as if I only had 2 Powerwalls, not 3 (even though the app always said I had 3). All 3 Powerwalls were on and glowing green on the sides. I also reset the Gateway and the Powerwalls multiple times during my testing to make sure that didn’t solve the problem.

I eventually got through to Tesla and had them run a diagnostic. Initially they saw nothing - everything looked fine. I asked them to look again and after more testing, they said something like “oh…it looks like one of your Powerwalls is in permanent standby.” So they confirmed that I had a Powerwall that wasn’t working correctly and opened a “Tier 2 ticket” or some such thing that hopefully someday will lead to the problem being fixed.

So my warning to everyone with multiple Powerwalls is:

You could have a completely non-functional Powerwall and the problem will not show up in your app and Tesla might never notice.​

So I recommend you do a sanity check (compare kWh usage vs % drained) periodically to make sure you have all the energy storage you paid for.

There were two other clues that I had a bad Powerwall. The first is that when I turned my Powerwalls off and on with the switch on the side, you could hear relays clicking inside 2 of them, but one was silent.

The second clue is that (labeling my 3 Powerwalls A, B, and C), I could turn off A and B, and C would continue to power the house. I could turn off A and C, and B would continue to power the house. But if I turned off B and C, there was no power.
 

BGbreeder

Member
Jun 19, 2020
560
355
Bay Area
Just had a Solar + 3 Powerwall system installed. Have been running off-grid while waiting for PTO. App shows 3 Powerwalls with a state of charge somewhere between 0% and 100%. Walls charge up to 100% during the day; house runs off Powerwalls when there’s no solar production.

After a week or two I got the feeling that the Powerwalls were discharging too quickly. As an example with nice round numbers, let’s say I was running off the Powerwalls for 13.5 hours between sunset and sunrise, and my house used an average of 1kW. So I would have drawn about 13.5kWh from the Powerwalls between when the panels stopped producing and when they restarted.

Since each Powerwall has 13.5kWh of energy, I basically used 1 Powerwall worth of energy overnight. But my app said I was at 50%, not 67% (as you’d expect with 3 Powerwalls). I did similar measurements and calculations over several days and concluded that my system was behaving as if I only had 2 Powerwalls, not 3 (even though the app always said I had 3). All 3 Powerwalls were on and glowing green on the sides. I also reset the Gateway and the Powerwalls multiple times during my testing to make sure that didn’t solve the problem.

I eventually got through to Tesla and had them run a diagnostic. Initially they saw nothing - everything looked fine. I asked them to look again and after more testing, they said something like “oh…it looks like one of your Powerwalls is in permanent standby.” So they confirmed that I had a Powerwall that wasn’t working correctly and opened a “Tier 2 ticket” or some such thing that hopefully someday will lead to the problem being fixed.

So my warning to everyone with multiple Powerwalls is:

You could have a completely non-functional Powerwall and the problem will not show up in your app and Tesla might never notice.​

So I recommend you do a sanity check (compare kWh usage vs % drained) periodically to make sure you have all the energy storage you paid for.

There were two other clues that I had a bad Powerwall. The first is that when I turned my Powerwalls off and on with the switch on the side, you could hear relays clicking inside 2 of them, but one was silent.

The second clue is that (labeling my 3 Powerwalls A, B, and C), I could turn off A and B, and C would continue to power the house. I could turn off A and C, and B would continue to power the house. But if I turned off B and C, there was no power.
Thanks for the tip. I will double check the math on the discharges.

I am deep in the "well, the switch doesn't do anything" with Tesla at the moment. They have run diagnostics and say that it is "OK", but don't have a response for "well, the switch doesn't do anything".

More when I know it...

All the best,

BG
 
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Yonki

Member
Supporting Member
Mar 31, 2015
601
1,771
Pacific Grove, CA
Guessing you may also be able to check the status through the TEG Powerwall API by browsing to https://TEG/api/powerwalls. If you are not already signed into the TEG, visit https://TEG/ first to sign in. Replace TEG in the URL with your local TEG IP address. (TEG = Tesla Energy Gateway)
I’ve been meaning to try out that API, will try this weekend. Thanks.
 

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