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.
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Powerwall 2 Available Energy After 2 Years
- Thread starter FLB46169
- Start date
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.
Wow! I was not expecting that much degradation so quickly...I guess maybe we will be looking at getting these replaced under warranty
eml2
Member
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).
I have my capacity tracked daily through the API. It's slowly but surely going down day by day as the temperature rises:
| 5/19/2021 | 40433 |
| 5/20/2021 | 40389 |
| 5/22/2021 | 40355 |
| 5/23/2201 | 40313 |
| 5/24/2021 | 40339 |
| 5/25/2021 | 40318 |
| 5/26/2021 | 40242 |
| 5/27/2021 | 40208 |
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.
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.
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.
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.
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Agreed. Battery capacity is an estimate based on indirect measurements like Coulumb counting, etc. and can vary.
That's why I look at trends rather than what it did on any particular day:
| 5/19/2021 | 40433 |
| 5/20/2021 | 40389 |
| 5/22/2021 | 40355 |
| 5/23/2201 | 40313 |
| 5/24/2021 | 40339 |
| 5/25/2021 | 40318 |
| 5/26/2021 | 40242 |
| 5/27/2021 | 40208 |
| 5/28/2021 | 40189 |
| 6/29/2021 | 40211 |
| 6/30/2021 | 40182 |
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.
Discussion: How to get status information from your Powerwalls
I havent seen anything like that in my model 3 either. its 2.5 years old as well. In any case, I wanted to validate what the "simple math" showed, which si why I wanted to know how to get data out of it. I am an IT person but not a coder. That is a concerning amount of degradation after only...
teslamotorsclub.com
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
