Tesla Powerwall Continuous Draw in Dual Installation

[Brovane]

According to the documents each Powerwall is supposed to be able to supply 5kw of power continuous and 7kw peak.

Shouldn't a installation with 2 Powerwall's be able to supply 10kw continuous?

 

[Bigtanuki]

You are correct. I am assuming you are not seeing that 10kW output. I had something similar that turned out to be a faulty cooling pump. I noticed that one of my two powerwalls had it's fan running hard while the other didn't have any fan action. This while charging my Model S at 12 kW. I checked the app and noted that while the units started off delivering 10kW the output started to fall after about 15 minutes. Since i was at about 12kW with the car charging I started out pulling ~2kW from the grid. The grid increased to pick up the load as the powerwall output fell, as expected.

After spending a good deal of time trying to make Tesla Energy understand my issue I finally got the offending Powerwall replaced under warranty. Fast forward about 6 months and I started to notice the same issue on the other original Powerwall unit. After many calls to Tesla Energy support (again!) I finally got some help. This was early April. I was told that I was now scheduled to have both of my Powerwalls replaced. I was told that there was some generic pump issue causing premature failure. However, since I was leaving on a 3 week vacation I asked to be reschduled to mid-May. I was told I would be contacted. Having heard that song and dance before, I wasn't surprised when I didn't receive a call after my return. So, many calls later, I was finally told that there was a shortage of PW units and I would hear from them, likely in June. I'm waiting....

p.s.

Note that Tesla says that the units won't fail catastrophically due to the pum issue. They just won't put out rated output. I'm thinking that condition constitutes a failure too, but what do I know.


Tesla Energy - If you're seeing this; you guys need to step up your game. The Powerwall 2 is a fabulous product and I am supremely happy with it, other than this issue. Install was wonderful and performance (with this exception) has met all of my expectations. Other than charging my vehicle during off-peak I haven't had to use any grid except during the middle of winter.


Bigtanuki
4.1 kWp PV / 2 PW2 units / 2017 MS90D

 

[Brovane]

Thank you for the reply.

I noticed a little bit difference behavior. I have never seen my power-wall system ever discharge above 6 KW and never consistently above 5.3kw. It will briefly spike up to around 6 KW and then start dropping back to around 5 KW. Even if I am putting a combined load over 10 KW on the house.

I think I am going to start with Swell Energy(My Installer) to question them and see how it goes from there. However to me something is not right.

 

[cwied]

I've seen the Powerwalls max out. As an aside on the cooling issue, Powerwall support told me that they'd be running a script intended to purge air from the cooling system for me next week because they saw high temperatures in my installation.

This screenshot is from a test I did April 30:

 

[boaterva]

Whoops, no picture. Can't you attach it here?

 

[Bigtanuki]

Thank you for the reply.

I noticed a little bit difference behavior. I have never seen my power-wall system ever discharge above 6 KW and never consistently above 5.3kw. It will briefly spike up to around 6 KW and then start dropping back to around 5 KW. Even if I am putting a combined load over 10 KW on the house.

I think I am going to start with Swell Energy(My Installer) to question them and see how it goes from there. However to me something is not right.

View attachment 306289

Are either or both of your fans running hard during max charging or output?

 

[Brovane]

Are either or both of your fans running hard during max charging or output?

That is a good question, I haven't checked that.

 

[Brovane]

Latest update from Swell is that Tesla ran some remote tests on my system. Tesla identified that the installer for my system (Horizon Solar Power) needs to come back out to recommission my system.

 

[Brovane]

Just got off the phone with Horizon Solar and the lady offered some more information.

Apparently my system never got the 2nd battery properly commissioned. Which is interesting because if I go directly to the gateway via IP and use the API to pull powerwalls status it shows both powerwalls serial numbers and that they are both in sync.

Not sure how both powerwalls could be in sync but only one powerwall working. They are sending a tech out on Thursday to fix the issue.

 

[Brovane]

Update:

One of my batteries is bad and Tesla will need to replace it. I have been given a ETA on how long this will take.

I do find it strange that despite one of my batteries being bad, the Gateway Display and Phone APP displays no errors that one of the batteries is not functioning. Apparently the battery has never functioned correctly since it was first installed.

 

[boaterva]

Update:

One of my batteries is bad and Tesla will need to replace it. I have been given a ETA on how long this will take.

I do find it strange that despite one of my batteries being bad, the Gateway Display and Phone APP displays no errors that one of the batteries is not functioning. Apparently the battery has never functioned correctly since it was first installed.

So it never works, the software thinks it did, but it's really busted.

Raises the question how you know the new one is any better.

 

[Brovane]

So it never works, the software thinks it did, but it's really busted.

Raises the question how you know the new one is any better.

Well according to Horizon when they went to recommission my unit, it comes up with a error that one of the batteries is bad.

Which to me also begs the question, what happened during the original commission process? I remember when Horizon was doing the commissioning it was late in the day and they had issues and had to call Tesla to assist in getting it commissioned.

For me the only way to tell both batteries is working is to place a continuous load of 6kw+ on system and see if it can draw this power from the batteries.

 

[miimura]

I had a similar but much more straight forward problem with my installation. When the batteries were installed and commissioned, the app showed a 13% SOC. After charging for a full sunny day it only showed 57% then stopped charging. It turned out that the breaker for only one of the two Powerwalls was turned on. Turning on the other breaker restored normal operation. There was no error indication in the app that anything was wrong, except the odd behavior.

 

[Brovane]

I had a similar but much more straight forward problem with my installation. When the batteries were installed and commissioned, the app showed a 13% SOC. After charging for a full sunny day it only showed 57% then stopped charging. It turned out that the breaker for only one of the two Powerwalls was turned on. Turning on the other breaker restored normal operation. There was no error indication in the app that anything was wrong, except the odd behavior.

To have one battery not functioning and the AP and Gateway to the customer show everything is just fine, I find that a absolutely horrible design by Tesla. At a minimum the Gateway should send send a alert back to Tesla that a tech might need to take a deeper look at the unit to make sure everything is functioning correctly.

I was suspicious shortly after the install that maybe both batteries were not functioning. However both batteries showed a solid green light. Then I went into the Gateway and pulled the Battery details by API and it showed both batteries and they were in Sync. I then dropped pursuing it further, until I started using my AC with TOU during peak times and noticed the battery not going above 5kw.

 

[Bigtanuki]

I would agree on all counts. My experiences with the Powerwall cooling issues were identified by me and I had to convince support that there was an issue. That was more than 6 months ago. My latest interactions with support have been much better with the powerwall support folks sounding a lot more like they really understand the system rather than just running down a script. Based on my experience with the cooling pumps and Tesla's response I'm thinking that there was a batch of units that failed prematurely. That being said, I would have been much happier if Tesla had contacted me up front once they identified the likely bad units. A system as sophisticated as the Powerwalls have been advertised as should be much better at self monitoring. Hopefully, they will get there in time.

As a side note, it seems like Tesla isn't falling into the trap of offshoring all of their support. Everyone I talked to on the phone sounded like a native english speaker and they all seemed to have a good understanding of the technical issues associated with the Powerwall.

As with all things Tesla things seem to be getting better with the current reality oversold, as usual. I'm happy enough with the Powerwalls to overlook a lot of the faults because from a practical standpoint, having ~27 kWh of power on hand keeps me fully utilizing my solar while charging the car and staying off of peak rates. I'm safely meeting the SGIP requirements to discharge the equivalent of 52 full battery charges annually. Even having to do a lot of manual hoop jumping is only a bit frustrating. At least with Tesla I'm reasonably confident that the functionality of the system is likely to improve over time and not remain stagnant. That's not something any other manufacturer is offering at this time, that I know of.

 

[Brovane]

The saga continues.

I found out on Monday that even though a case with Tesla was opened by the Horizon Solar tech on June 7th. The Tesla tech basically dropped the case with no explanation and did nothing to start a RMA!!!

Another case was opened on 6/18 and the bad Powerwall now has a RMA started which will take 4-6 weeks from 6/18 for the replacement unit to arrive. I talked to the support person on the phone about why a RMA wasn't started on 6/7. They reached out to the tech from 6/7 and that tech had no explanation as to why the RMA wasn't started.

To make things look even worse for Tesla. They confirmed they had received an alert on April 11th that one of Powerwall units wasn't functioning correctly. Yet nobody at Tesla acted on this alert and they just ignored it until I reported that my Powerwall wasn't functioning correctly when I couldn't get a continuous draw above 5kw+ from the two units. The phone person assured me that they now have a new team which just started this week to look at these alerts. I cannot fathom how Tesla is just figuring this out now that they should have a team looking at alerts from Powerwall's in the field. Especially when you consider they deny to the customer the ability to receive these same type of alerts.

Not real impressed. Having 2nd thoughts of ever purchasing a car from this company.

 

[Brovane]

Update on the RMA.

Called Tesla yesterday for a update.

Tesla told me they are waiting for Horizon Solar (Installer) to get back to them with a ship to address. Tesla instead of calling Horizon Solar main number was calling the installer that initiated the RMA process. Since Tesla regularly ships Powerwalls to Horizon I am not sure why they couldn't figure out the ship to address. Got the RMA# from Tesla and call back information and passed this along to the main office of Horizon and they are going to reach out to Tesla. Hopefully we should see some more action soon.

Interesting once the latest firmware update was done 1.20.0 my Tesla app shows 2xPowerwalls now. It also only charges the system to 50% now which more accurately reflects that I have only one battery working.

 

[boaterva]

Update on the RMA.

Called Tesla yesterday for a update.

Tesla told me they are waiting for Horizon Solar (Installer) to get back to them with a ship to address. Tesla instead of calling Horizon Solar main number was calling the installer that initiated the RMA process. Since Tesla regularly ships Powerwalls to Horizon I am not sure why they couldn't figure out the ship to address. Got the RMA# from Tesla and call back information and passed this along to the main office of Horizon and they are going to reach out to Tesla. Hopefully we should see some more action soon.

Interesting once the latest firmware update was done 1.20.0 my Tesla app shows 2xPowerwalls now. It also only charges the system to 50% now which more accurately reflects that I have only one battery working.

Well, at least your normal data (charging) shows something now (and not needed to do a high discharge (if you want to call it that) to prove the issue). Baby steps.

Yeah, I know, it's all nuts. Those of us on the car side adding your side know what you are facing. At least when you get to the car side, tons and tons of these sort of things have already been worked out.

 

[Brovane]

I was hoping to have better news after today.

Horizon Solar came out to replace the single Powerwall for my 2xPowerwall system that required replacement.

The Powerwall that was shipped as a RMA replacement was a refurbished Powerwall. After replacement of the bad PW they cannot get the refurbished unit to work. The Horizon Solar techs spend 2+ hours on the phone with Tesla and went through several layers of tech support and they couldn't get the replacement unit to work. They have escalated the issue internally within Tesla. To add insult to injury both PW's are now not working including the previous working good one. So after the work performed today my 2xPW system is completely non-functioning. Basically a $20k system at this point is a expensive garage decoration.

Let's just say I am not pleased at all.

 

[Brovane]

Latest update.

Nobody has reached out to me from Tesla.

However on Thursday I went into the garage and heard the fans going in both of my PW's and I then checked the app.

The PW's were putting out 8kw to the house which I had never seen before. So apparently sometime Wednesday or Thursday somebody from Tesla went remotely into my system and fixed the issue remotely and was able to get my system properly commissioned.

I confirmed on Friday that the system was now able to charge to 100% and I finally have a full functioning system for the first time.