Powerwall 2 Available Energy After 2 Years

[FLB46169]

First time poster, long time visitor. I'm trying to understand the current energy retention level of my 2 year old Powerwall 2's. They don't seem to be holding the kWh's I expect. I'll share some numbers I've got and would like to hear from others if I'm looking at this the right way.

My two Powerwalls are set to 20% reserve and they hit the reserve level around 3 AM this morning. The Tesla app actually showed 18%, the browser version showed 22%. All good so far.

At about 1:10 PM today, the app shows that 17 kWh's were sent to the PW 2's and both the app and browser show 100% batteries.

Here's what I'm trying to figure out. 17 kWh's seems low for batteries that are supposed to hold 27 kWh's new. That equates to 63% of the original usable capacity. And that's the "To" the PW number. If the 90% roundtrip number is correct, that's only 15.3% "From" the PW's when I need it.

80% of new would be in the 21.6 kWh range for 2 new batteries. I'm sure there is some degradation, but 63% would be under the warranty provision and concerning.

Attached is a screenshot showing the PW activity I'm referencing.

Looking forward to help on whether I'm looking at this correctly, or this is normal behavior. Thanks.

 

[jjrandorin]

Have you contacted tesla energy support with your concern? They are warrantied to have at least 70% capacity for at least 10 years, so thats where you should start if this is what you believe.

Rather than "doing the math", on the day before a day you expect to have good sun, why not set your reserve to zero (even better if you have an EV so you can drain them on demand) and drain your batteries to zero, then when they hit zero, switch to backup only and let them fill completely up, and see what it reports that total is.

 

[FLB46169]

Understood, just wanted to see if I was looking at this correctly before I make the call. I put in a service request in the App and waiting for them to respond.

 

[jjrandorin]

Understood, just wanted to see if I was looking at this correctly before I make the call. I put in a service request in the App and waiting for them to respond.

I wouldnt bother with a service request in the app, personally. Response times to that is basically "very long" to "non existent". Call them (old school phone call) if you want to talk to someone and have them examine it, and possibly escalate to the next level. With a phone call you will hear from them "now", with an app request you MAY here from them in a week or two.

 

[FLB46169]

Thanks for the recommendation. I contacted Tesla and they are able to pull the capacity for each PW. They pulled mine and after two years, my usable capacity is down to 10 kWh's per battery. So at 74% of original capacity, they see no issues at this point. There is no way to measure this on our end. Tesla is able to pull the signal on their end.

So, in my case, I've got 26% degradation after 2 years since PTO. They jumped to the warranty response very quickly. Not enough to trigger a warranty issue. Should be an interesting next 7 years 11 months.

At least I now know what percentage to change my reserve to based on my home usage.

 

[wjgjr]

FYI, others have worked out a way to see this number using the cloud-based API. One thread:

Discussion: How to get status information from your Powerwalls

Since we have a warranty that specifically covers degradation over 10 years, is there any way to actually monitor it? When I log in to the gateway, i don't see it. I know there are a few undocumented json paths for more info, but I don't know them all. Just wondering if there is a way other...

teslamotorsclub.com

This might be a way to validate that the numbers roughly match the 74% number Tesla provides and also watch for it to drop below 70%.

 

[wwhitney]

FYI, others have worked out a way to see this number using the cloud-based API. One thread:

Discussion: How to get status information from your Powerwalls

Since we have a warranty that specifically covers degradation over 10 years, is there any way to actually monitor it? When I log in to the gateway, i don't see it. I know there are a few undocumented json paths for more info, but I don't know them all. Just wondering if there is a way other...

teslamotorsclub.com

When I try that method, curl step 1 gives me a response that includes "Endpoint deprecated: Please update your App." Any pointers to the current procedure?

Cheers, Wayne

 

[getakey]

Thanks for the recommendation. I contacted Tesla and they are able to pull the capacity for each PW. They pulled mine and after two years, my usable capacity is down to 10 kWh's per battery. So at 74% of original capacity, they see no issues at this point. There is no way to measure this on our end. Tesla is able to pull the signal on their end.

So, in my case, I've got 26% degradation after 2 years since PTO. They jumped to the warranty response very quickly. Not enough to trigger a warranty issue. Should be an interesting next 7 years 11 months.

At least I now know what percentage to change my reserve to based on my home usage.

wow, that is a lot of degradation. Hoping you got some lemons and that it is not a common issue

 

[jjrandorin]

Thanks for the recommendation. I contacted Tesla and they are able to pull the capacity for each PW. They pulled mine and after two years, my usable capacity is down to 10 kWh's per battery. So at 74% of original capacity, they see no issues at this point. There is no way to measure this on our end. Tesla is able to pull the signal on their end.

So, in my case, I've got 26% degradation after 2 years since PTO. They jumped to the warranty response very quickly. Not enough to trigger a warranty issue. Should be an interesting next 7 years 11 months.

At least I now know what percentage to change my reserve to based on my home usage.

TBH I have a somewhat similar situation myself, which is why I mentioned to you to call via phone. I have about 25% degradation, according to Tesla Energy Tier 1 support, and my powerwalls are about 1.5 years old. For about 24 hours it made me frustrated, then I thought to myself: There is no way that these things wont degrade another 5% in the next 8.5 years. So, I am not sure how you feel about it, OP, but what this means to me is that at some point they will drop below the value for warranty replacement, and they will have to be replaced.

OP, I use self powered mode, no idea what mode you use. I have not changed anything about my usage pattern at all. My reserve is set to 20% right now, and I go from 100% to about 25% daily, and am using virtually no energy from the electrical grid, same as I did last year.

Said another way, I am continuing to "use my powerwalls" with the expectation that, at some point in the next couple of years, they will lose another few percentage points of capacity, and will need to be warranty replaced. I have no qualms at all about "using the battery" because I am simply using it in the manner it was designed.

I came to the realization that I would much rather have this much degradation in the powerwalls now, than have them be at 26% in year 9 or something, where they would likely (with my luck) drop below the warranty value right after the 10 year installation anniversary.

 

[jjrandorin]

One more thing I will say on this as I feel its somewhat relevant. With also owning a tesla vehicle, I am aware that, there is a somewhat random nature to how various batteries perform over time. In the model 3 forums, it has sometimes been referred to as a "battery lottery". What i mean is, sometimes, one persons battery does a little better (or worse) over time than another persons.

My model 3 is at the high end of capacity left for its age / mileage, with something like 7-8% degradation over a 2.5 year timeframe. I take no particular steps with it, I plug it in every time it hits my garage to 90% charge. There are pages (and pages and pages and pages and pages and pages and......) of back and forth discussions about batteries on these boards, but in general, some people just have one that degrades a little more / faster than others.

I expect this to be the case here too. My model 3 is at the high side of capacity left (low degradation) while I feel my powerwalls is at the lower side of capacity left at this point (higher degradation) but as I mentioned I realized I was actually somewhat happy with this, since its enough degradation to believe they will get warranty replaced at some point over the next 8.5 years.

 

[h2ofun]

One more thing I will say on this as I feel its somewhat relevant. With also owning a tesla vehicle, I am aware that, there is a somewhat random nature to how various batteries perform over time. In the model 3 forums, it has sometimes been referred to as a "battery lottery". What i mean is, sometimes, one persons battery does a little better (or worse) over time than another persons.

My model 3 is at the high end of capacity left for its age / mileage, with something like 7-8% degradation over a 2.5 year timeframe. I take no particular steps with it, I plug it in every time it hits my garage to 90% charge. There are pages (and pages and pages and pages and pages and pages and......) of back and forth discussions about batteries on these boards, but in general, some people just have one that degrades a little more / faster than others.

I expect this to be the case here too. My model 3 is at the high side of capacity left (low degradation) while I feel my powerwalls is at the lower side of capacity left at this point (higher degradation) but as I mentioned I realized I was actually somewhat happy with this, since its enough degradation to believe they will get warranty replaced at some point over the next 8.5 years.

Assuming they do not find a contact comments that lets them out of the warranty

 

[getakey]

For PWs, is the warranty replacement prorated or just replace in full. By prorated, I mean if you got 5 years out of them before <70% is reached, do you have to pay 50% of the replacement?

 

[h2ofun]

For PWs, is the warranty replacement prorated or just replace in full. By prorated, I mean if you got 5 years out of them before <70% is reached, do you have to pay 50% of the replacement?

great question

 

[h2ofun]

One more thing I will say on this as I feel its somewhat relevant. With also owning a tesla vehicle, I am aware that, there is a somewhat random nature to how various batteries perform over time. In the model 3 forums, it has sometimes been referred to as a "battery lottery". What i mean is, sometimes, one persons battery does a little better (or worse) over time than another persons.

My model 3 is at the high end of capacity left for its age / mileage, with something like 7-8% degradation over a 2.5 year timeframe. I take no particular steps with it, I plug it in every time it hits my garage to 90% charge. There are pages (and pages and pages and pages and pages and pages and......) of back and forth discussions about batteries on these boards, but in general, some people just have one that degrades a little more / faster than others.

I expect this to be the case here too. My model 3 is at the high side of capacity left (low degradation) while I feel my powerwalls is at the lower side of capacity left at this point (higher degradation) but as I mentioned I realized I was actually somewhat happy with this, since its enough degradation to believe they will get warranty replaced at some point over the next 8.5 years.

And with the SGIP requirement that the batteries have to cycle, if there are issues, I guess I would find out sooner than if I just had them on backup mode only.

 

[Redhill_qik]

Thanks for the recommendation. I contacted Tesla and they are able to pull the capacity for each PW. They pulled mine and after two years, my usable capacity is down to 10 kWh's per battery. So at 74% of original capacity, they see no issues at this point. There is no way to measure this on our end. Tesla is able to pull the signal on their end.

So, in my case, I've got 26% degradation after 2 years since PTO. They jumped to the warranty response very quickly. Not enough to trigger a warranty issue. Should be an interesting next 7 years 11 months.

At least I now know what percentage to change my reserve to based on my home usage.

This may only be for Powerwalls that have been upgraded to v21.13.2, but after you login to your TEG Powerwall Gateway (https://teg/ or https://#.#.#.# where # is the TEG IP address) then you can use this API URL https://teg/api/system_status (replace teg with the IP address if that is how you logged in) to get the JSON data for each PW that you have. The field(s) that you want to look for is nominal_full_pack_energy and there will be one for each battery_block. The reported value is in watts, so for my two I am getting 27470 combined and individually 13782 and 13688 (6.5 months in service).

 

[jjrandorin]

This may only be for Powerwallrs that have been upgraded to v21.13.2, but after you login to your TEG Powerwall Gateway (https://teg/ or https://#.#.#.# where # is the TEG IP address) then you can use this API URL https://teg/api/system_status (replace teg with the IP address if that is how you logged in) to get the JSON data for each PW that you have. The field(s) that you want to look for is nominal_full_pack_energy and there will be one for each battery_block. The reported value is in watts, so for my two I am getting 13782 and 13688 (6.5 months in service).

I havent been able to get that to work on 20.49 which is what I am on now, but figured it might be firmware version related.

For PWs, is the warranty replacement prorated or just replace in full. By prorated, I mean if you got 5 years out of them before <70% is reached, do you have to pay 50% of the replacement?

Thats a good question actually. My expectation is simply "replacement with a refurbished, like new unit" (I dont expect a brand new one, but do expect one thats been refurbished like new). Assuming I am still visiting this website either in a moderator capacity or regular user capacity when I reach that point, I will post and let people know my experience with the process.

I suspect that will happen in the next 12 months or so, unless my units stop degrading all together, and batteries dont work that way, so I actually feel like I am in decent shape to exercise the warranty in the next 12-18 months.

 

[h2ofun]

I havent been able to get that to work on 20.49 which is what I am on now, but figured it might be firmware version related.



Thats a good question actually. My expectation is simply "replacement with a refurbished, like new unit" (I dont expect a brand new one, but do expect one thats been refurbished like new). Assuming I am still visiting this website either in a moderator capacity or regular user capacity when I reach that point, I will post and let people know my experience with the process.

I suspect that will happen in the next 12 months or so, unless my units stop degrading all together, and batteries dont work that way, so I actually feel like I am in decent shape to exercise the warranty in the next 12-18 months.

What is your feeling in the future as to what percentage of batteries might have this issue? Or could tesla be assuming most folks would not even notice?

 

[holeydonut]

TBH I have a somewhat similar situation myself, which is why I mentioned to you to call via phone. I have about 25% degradation, according to Tesla Energy Tier 1 support, and my powerwalls are about 1.5 years old. For about 24 hours it made me frustrated, then I thought to myself: There is no way that these things wont degrade another 5% in the next 8.5 years. So, I am not sure how you feel about it, OP, but what this means to me is that at some point they will drop below the value for warranty replacement, and they will have to be replaced.

OP, I use self powered mode, no idea what mode you use. I have not changed anything about my usage pattern at all. My reserve is set to 20% right now, and I go from 100% to about 25% daily, and am using virtually no energy from the electrical grid, same as I did last year.

Said another way, I am continuing to "use my powerwalls" with the expectation that, at some point in the next couple of years, they will lose another few percentage points of capacity, and will need to be warranty replaced. I have no qualms at all about "using the battery" because I am simply using it in the manner it was designed.

I came to the realization that I would much rather have this much degradation in the powerwalls now, than have them be at 26% in year 9 or something, where they would likely (with my luck) drop below the warranty value right after the 10 year installation anniversary.

Lol, my "glass is half full" perspective is that since the measurement of the "out of spec" battery is made by Tesla themselves, then they simply always tell you that the battery is at "71%" capacity. They can keep denying your warranty claim until 10 years and 1 day.

I used to work with a major automobile manufacturer and that was one way to make sure those hippies in California wouldn't be able to claim that insanely long warranty on their fancy hybrid car batteries.

Good luck to any consumer who is willing to find a way to do a test to prove their batteries dropped below 70% when "fully charged".

 

[sorka]

Thanks for the recommendation. I contacted Tesla and they are able to pull the capacity for each PW. They pulled mine and after two years, my usable capacity is down to 10 kWh's per battery. So at 74% of original capacity, they see no issues at this point. There is no way to measure this on our end. Tesla is able to pull the signal on their end.

So, in my case, I've got 26% degradation after 2 years since PTO. They jumped to the warranty response very quickly. Not enough to trigger a warranty issue. Should be an interesting next 7 years 11 months.

At least I now know what percentage to change my reserve to based on my home usage.

At your current rate you'll dip below 70% in a few months. The interesting thing will be how many times they need to replace your powerwalls over 10 years.

Once summer heat hits, I'll be cycling through 100% of my powerwall capacity (reserve set to 0%) running my AC in 110F weather. The powerwalls are outside. They are going to get absolutely fried.

On the day of the install, I asked the installer about putting them in the garage but he said it would take a lot longer and it made no difference to the life of the batteries. He totally lied because he wanted his job to be quicker and easier. I notified Tesla later after I did more research and realized that my summer temps are way outside the maximum 84 F optimal operating range. I offered to let them relocate my powewalls inside my garage where the temperature maxes out at about 85F when it's 110F outside. They replied that they could do it for $3300. I replied back that I wasn't spending money to extend the life of their product that is already warrantied for 10 years. When my 3 PWs dip below 70% in 2 years or less, I'll let them decide if they want to keep replacing them or move them to a more hospitable environment.


Has nobody yet discovered the API to pull capacity from the powerwalls?

 

[sorka]

I came to the realization that I would much rather have this much degradation in the powerwalls now, than have them be at 26% in year 9 or something, where they would likely (with my luck) drop below the warranty value right after the 10 year installation anniversary.

Almost guarantees your PWs will be replaced sometime in the 10 year warranty period with a more robust chemistry.