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Powerwall 2 Available Energy After 2 Years

FLB46169

Member
Mar 12, 2021
20
35
Ocala, FL
Just a follow up to my original post. Powerwall Support contacted me from my service request through the app. Their research shows each Powerwall now has a capacity of 10.3 kWh's. So 76% of original, and as they are quick to point out, above the 70% warranty number. I told them I was surprised at the speed of degradation over 24 months and will continue to monitor it. Thanks for all the responses.
 

Redhill_qik

Member
Aug 16, 2020
343
241
South SF Bay, California
Just a follow up to my original post. Powerwall Support contacted me from my service request through the app. Their research shows each Powerwall now has a capacity of 10.3 kWh's. So 76% of original, and as they are quick to point out, above the 70% warranty number. I told them I was surprised at the speed of degradation over 24 months and will continue to monitor it. Thanks for all the responses.
You mentioned in your first post that you have the reserve level set to 20%. How often do you think you hit this level over the last two years? Every night?
 

FLB46169

Member
Mar 12, 2021
20
35
Ocala, FL
You mentioned in your first post that you have the reserve level set to 20%. How often do you think you hit this level over the last two years? Every night?
Now, I hit this level every night due to our AC running with the warmer weather. I don't hit in in milder temps. If we expect multiple days with heavy cloud cover, I raise the reserve to give us at least 4 hours of backup.
 

SVDNN

Member
Sep 23, 2018
66
36
SF Bay Area
Just a follow up to my original post. Powerwall Support contacted me from my service request through the app. Their research shows each Powerwall now has a capacity of 10.3 kWh's. So 76% of original, and as they are quick to point out, above the 70% warranty number. I told them I was surprised at the speed of degradation over 24 months and will continue to monitor it. Thanks for all the responses.

Wow! I was not expecting that much degradation so quickly...I guess maybe we will be looking at getting these replaced under warranty:rolleyes:
 

eml2

Member
Sep 28, 2017
275
215
Massachusetts
I have my 2 PW2 for 3.5 years. The Total Pack Energy reported from owner-api as of today is 27.017 kwh. My PW2 are in the basement. Temp in the basement is between 50 - 70F. During the winter months, PW is often drained to 5%, sometimes down to 0%.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,874
12,597
Riverside Co. CA
I have my 2 PW2 for 3.5 years. The Total Pack Energy reported from owner-api as of today is 27.017 kwh. My PW2 are in the basement. Temp in the basement is between 50 - 70F. During the winter months, PW is often drained to 5%, sometimes down to 0%.

Thats a great result! My (2) powerwall 2s are inside my garage, which is fully enclosed and drywalled, and ranges from 50 degrees to a high of about 85 degrees or so in full summer heat. I use self powered mode, and my reserve fluctuates (by me self micro managing it, lol) from 5-10% in the spring - summer - fall, to 30-35% in the winter (or what passes for winter where I live).
 

sorka

Well-Known Member
Feb 28, 2015
8,283
6,246
Merced, CA
I have my 2 PW2 for 3.5 years. The Total Pack Energy reported from owner-api as of today is 27.017 kwh. My PW2 are in the basement. Temp in the basement is between 50 - 70F. During the winter months, PW is often drained to 5%, sometimes down to 0%.

That's like brand new capacity, right?
 

holeydonut

Supporting Member
Supporting Member
Jun 27, 2020
2,237
1,625
East Bay NorCal
I have my capacity tracked daily through the API. It's slowly but surely going down day by day as the temperature rises:
5/19/202140433
5/20/202140389
5/22/202140355
5/23/220140313
5/24/202140339
5/25/202140318
5/26/202140242
5/27/202140208

Wow, I really hope that change is tied to a steady rise in ambient temperature. Like has it really gone from like 70F to 90F or something in Merced?
 

sorka

Well-Known Member
Feb 28, 2015
8,283
6,246
Merced, CA
Wow, I really hope that change is tied to a steady rise in ambient temperature. Like has it really gone from like 70F to 90F or something in Merced?

In fact it has gone from 70 to 90 in the last month.

But typically BMSs report higher capacities as temps rise.
 

zƬesla

Member
Apr 16, 2020
425
161
US-NH
For what it's worth...
2 PWs installed in May 2020. In August 2020 when I started tracking it was at 27674. In March 2021, it was at 27268.
3rd PW installed in April 2021. Shortly after, logs show 40780 (and 40821 next day). Just over a month later, it's at 40812.
I do see a bit of variation, possibly based on how fully charged PWs are.
 

sorka

Well-Known Member
Feb 28, 2015
8,283
6,246
Merced, CA
I have my capacity tracked daily through the API. It's slowly but surely going down day by day as the temperature rises:
5/19/202140433
5/20/202140389
5/22/202140355
5/23/220140313
5/24/202140339
5/25/202140318
5/26/202140242
5/27/202140208

The next reading today is 40189...so still decreasing and up to now, I've only been using about 25% depth of charge in optimal temperatures. Next week it shoots up to a hundred and we'll start using the AC every day and will go through 80 to 90% of the depth of charge every day. If it turns out Tesla has a problem with a high rate of PW2 degradation, they'll make changes that make it harder to use them...either capping how quickly you can charge or how long and deep you can discharge them. On the 85 packs for the cars, with a single software update, the massively lowered the supercharging speed and on a number of cars artificially capped the capacity to prevent the batteries from being fully charged, so I don't believe for a second they won't do something similar here.

It's likely such changes would first be deployed for higher environmental temperatures. My PWs will be sitting in 110F temps for a about a month each summer which is when they'll get absolutely the highest usage at 100% depth of charge every day during that month. I asked them about instaling them in my 1500 square foot almost almost empty garage. The installer, who was Tesla employee, said it wouldn't make any difference in the garage vs outside in the breezeway for product performance and lifetime. I now believe he said that because it would have taken a few more hours to mount them on the wall inside and run the 10 feet extra conduit rather than what he did which is mount them on the walkway outside next to the TEG and inverter.
 
Last edited:

yblaser

Member
Aug 4, 2018
88
61
South Bay Los Angeles
Keep in mind that these values are the BMS's estimates of capacity. The estimate can be off by a decent amount especially if the battery isn't being cycled deeply. Personally I wouldn't put any value to changes less than 5%.
 
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jboy210

Supporting Member
Supporting Member
Dec 2, 2016
5,517
3,507
Northern California
Keep in mind that these values are the BMS's estimates of capacity. The estimate can be off by a decent amount especially if the battery isn't being cycled deeply. Personally I wouldn't put any value to changes less than 5%.
Agreed. Battery capacity is an estimate based on indirect measurements like Coulumb counting, etc. and can vary.
 

sorka

Well-Known Member
Feb 28, 2015
8,283
6,246
Merced, CA
Keep in mind that these values are the BMS's estimates of capacity. The estimate can be off by a decent amount especially if the battery isn't being cycled deeply. Personally I wouldn't put any value to changes less than 5%.

That's why I look at trends rather than what it did on any particular day:

5/19/202140433
5/20/202140389
5/22/202140355
5/23/220140313
5/24/202140339
5/25/202140318
5/26/202140242
5/27/202140208
5/28/202140189
6/29/202140211
6/30/202140182
 

getakey

Active Member
Jan 28, 2020
1,452
475
95762
I have 3 PWs and they were installed 18 months ago. How do you check total capacity?
Yesterday, my "from PW" was 15.9 kWh and it took it down to 54% charge. That would seem to be 29.4 total kWh or 73% of what it should be.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,874
12,597
Riverside Co. CA
I have 3 PWs and they were installed 18 months ago. How do you check total capacity?
Yesterday, my "from PW" was 15.9 kWh and it took it down to 54% charge. That would seem to be 29.4 total kWh or 73% of what it should be.

The easiest way I am aware of is the post made here by @mjhwa to provide a walkthrough on how we can do this using free google account and tools.

 

Redhill_qik

Member
Aug 16, 2020
343
241
South SF Bay, California
I have 3 PWs and they were installed 18 months ago. How do you check total capacity?
Yesterday, my "from PW" was 15.9 kWh and it took it down to 54% charge. That would seem to be 29.4 total kWh or 73% of what it should be.
If you have firmware 21.13.2 or higher then you can log into the gateway and then go to this REST API page.

Replace the IP address with your gateway IP addresses
 

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