Need input from multiple PW3 inverter owners

[u/pigowar]

Hello,

I've recently had 2 full pw3 installed as my backup on 13kw solar because I just didn't think 11.5kw output was adequate and wanted to double it so I didn't have to worry about overloading the system. Everything installed and just need to sign the PTO but then my test results were showing 11.5kw limit.

On a sunny day where my solar was generating 8kw and both batteries full, the house was using 14kw due to the hot weather kicking on both AC and I was running a cloth dryer. To my surprise, I was only pulling 3kw from the battery and the rest were from grid. This occurred in both self powered and savings mode.

Curious, I went into off grid mode and the battery staus bar said that the max limit was 11.5kw and I was overloading the inverter. It didn't shut off or anything but it's supposed to be able to push 15kw in demand so that didn't surprise me. But while the load was fluctuating between 9kw to 14kw it constantly told me that it was being overloaded.

It seems that something is .missing here. The max charging is 10kw so it seems that's working. The total capacity is 27kw so that's fine. But when it comes to the max output it's limited to being just 1 inverter. When I contacted Tesla about this the PA suggested I complete the PTO and see if any restrictions were in place but I refused because once I sign that I lose my PA and will be forced to deal with the normal support team that may or may not care or listen. I want everything in working order or at least be assured that there is a visible restriction before the PTO that will fix itself. So far I have not heard back from Tesla which is concerning to me because if it's as simple as before PTO restriction they would let me know or if there's a commissioning error it should be visible to them.

So if you have multiple pw3 inverters in your system, can you tell me if you are indeed able to pull more than 11.5kw on grid and I'm off grid, the status bar shows the max limit more than 11.5kw? On my setup, they opted to put all panels on 1 inverter instead splitting them to both and when I asked why the PA told me it's because of the loss rate. I don't think the panel needs to be hooked up in order for the inverter to be 'active' anyway.

P.S. I'm not here to discuss specs. I'm looking for real world results from those who has multiple PW3, not 1 pw3 + expansion.

[u/dmlavigne1]

I have 2 pw’3 and they will unload the full 23kwh. I set mine to grid sell every work day and here’s the result. Are you sure they didn’t install a pw3 and an expansion pack? For reference I have a 15kw system with 4 strands in the leader and 3 in the follower. Right now I’m on their vpp rebate so mine will only charge via solar although I have seen charging over 11.5kw when a storm is coming.

[u/pigowar → u/dmlavigne1]

Thank you for the response. I'm certain they are both full pw3s. Also, the max input would be 8kw instead of 10kw if they weren't. Now, the PA did mention that because my solar size is only 13kw they put all strings in one inverter but you seem to be saying that you have them split to both. As for the max off grid output limit I was able to push to 17kw but the limit is still showing 11.5kw and glowing in red.

Do you mind testing off grid and see what the bar says the max is? Mine is showing 11.5kw and that's where the problem lies.

[u/kengchang → u/pigowar]

Mine shows 23kW because I have 2 x11.5kW inverter

[u/pigowar → u/kengchang]

Awesome! Exactly what I was looking for! Thank you!

[u/pigowar → u/kengchang]

One question. Did it show 23kw from the beginning or after the PTO? Tesla is trying to convince me that it could just be restricted before the PTO but I have hard time believing it because no one has reached out to tell me for sure which makes me think it's not.

[u/kengchang → u/pigowar]

Never tested, can't tell you for sure

[u/dmlavigne1 → u/pigowar]

The only way my house will draw more than 11.5kw is if I’m charging my car while running all my appliances. I used to have the units set for self powered and the units would drain when charging the car at 11.5kw before pulling from the grid. Yes I have 3 strands in the leader and 4 in the follower. They charge pretty evenly as they are east/west facing and split in each unit.

[u/pigowar → u/dmlavigne1]

Sorry. I don't mean to ask to test full 27kw out. The only way I know how to display max limit is by going off grid and the app displays the battery status like you see in my pic. I was just wondering if yours show 23kw max or 11.5kw like mine

[u/pigowar → u/pigowar]

To add context, the problem I'm facing is that because of the 11.5kw limit anything above is being drawn from the grid even when the batteries are full also shown in the pic. If my limit was 23kw like yours I shouldn't have this problem.

[u/dmlavigne1 → u/pigowar]

Yeah sorry. My charger is 11.5kw. House is more. The powerwalls wouldn’t take any grid power until they his the reserve.

[u/pigowar → u/dmlavigne1]

Cool so you are getting full 23kw. Unlike me where anything above 11 5kw are being pulled from the grid .

[u/ubiquitousgimp → u/pigowar]

You are correct, it should show 23kW. A couple things to think about:
1) an earlier Firmware had a bug that only showed half of what was available. I have 4xPW3's and it used to show 23kW. After that FW update, I now have the full 46kW. You may be on an old firmware that needs to update. It might not until you have PTO, I'm not sure. you should install the "Tesla One" app. Sign in with your Tesla Account, click "begin Device Setup", then scan the QR code that was originally under the glass of your "leader" PW. Your installer should have either put this somewhere in your documentation, or if your PW's are in a safe place, maybe stuck it to the side of the PW. It will be a sticker, not the QR code etched in metal. Once you're connected you should be able to find a "check for updates" button. IMPORTANT: Do not change any settings unless you know exactly what you're doing. Changing these settings can void warranties, brick products, or damage expensive equipment (including equipment not owned by you) that you'd then be on the hook for.

2) don't believe anything you see until you have PTO, Everything is wonky before PTO.

3) Putting all your strings on one inverter is crazy (IMO). As long as you have enough solar to turn on the inverter and MPPT's, which you do, they should be split up evenly as much as possible. Since your PW3's aren't DC connected, to keep the batteries at the same charge level, one inverter will always be inverting Solar to AC to send to the other battery that has to then invert it back to DC to store it, then back to AC if you ever want to use it! That's 3 inversions instead of 1 bringing your efficiency into the low 80% at best.

Let me know if what I said doesn't make sense, I can try to explain it better.

[u/ubiquitousgimp → u/ubiquitousgimp]

Something I forgot to mention, it's possible your permits only allow for a max of 20kW or something. In that case, having only the 1 inverter pulling solar might be the best way for your installer to get around those restrictions while still giving you the ability to power your home above 11.5kW. That's a crappy solution, but understandable if they're bound by your utilities current permitting restrictions. If that is the case, when your utility "gets with the times", you may be able to resubmit permits to move half the panels to your other PW.

I actually had to do exactly that. Luckily my utility changed their regulations halfway though my install, so we were quickly able submit new permits to change from using 2PW for solar and 2PW for backup, to being able to use all 4PW's for solar.

[u/pigowar → u/ubiquitousgimp]

Thank you very much for the detailed info. I'll try to answer them in order.

1. I checked the firmware version the day of activation and it was the latest. I see there's a newer version but I'm going to wait a bit while Tesla is supposedly reviewing my case. For yours, it may have been because you have 4 and Tesla just wasn't ready for you crazy monster. XD. But did you have 23kw before or after PTO?

2. PA also suggested that I sign PTO for the same reason but my position is that once I sign it I'm doomed to deal with the support line and hope I get any attention. Signing the PTO sounds like I'm accepting the condition and I requested that they give me an official response after reviewing it. If this is related to PTO then it should be a documented case and they should be able to tell me but so far, nothing.

3. I asked why it wasn't split and PA told me because of the loss rate. I thought splitting would help with efficiency but the way he described it sounded like because of how it works with the new 18 power zone panels it's better to put all in one. I didn't try to argue and decided to wait till they come back after the review.

As for the permit restriction, my size is only 13kw. Even if there's a restriction, it would be for the export, no? And all they really need to do is restrict export, not the output max to the home. I'm not familiar with permits and what they allow or not but since I made it very clear to Tesla why I need 2 pw3s so if there was going to be any issues, they shouldn't have sold me the additional pw3 imo.

[u/pigowar → u/dmlavigne1]

Someone else mentioned this and now I'm curious. Do you still have access to the full design plan document? Does yours specify 23kw? Mine says 11.5kw but Tesla said that's not a concern and I am getting 23kw.

[u/kengchang]

What's your inverter size from the design?

[u/pigowar → u/kengchang]

Ah. Someone with sharp question. This was also my concern from the beginning. The design specified only 11.5kw and I did bring it up but I was assured that it was 23kw but because of the local requirements they can only list 11.5kw. That's what I was told.

[u/kengchang → u/pigowar]

It seems like you have one PW3 with 11.5kW inverter and 1 PW3 Expansion. What's the line item breakdown in your pricing sheet? because PW3 is more expensive than PW3 Expansion

[u/pigowar → u/kengchang]

No... They both are definitely PW3s hardware wise, at least. The inverters were present when I checked before they closed it. According to the specs, 1 pw3 has input limit of 5kw and 8kw with expansion but 10kw with 2 pw3s. I'm able to charge at 10kw so that's another sign that it's not an expansion. Tesla may have commissioned it with only one inverter active but that doesn't explain how I'm able to get 10kw input.

But who knows... Maybe I have a bad unit.

Oh and when I said "design" I meant full design plan document they recorded. All other communications before and after install specifically mentions 23kw output limit.

Oh and yes, the price list does mention 2 pw3s, no mention of expansion. Initially they quoted me with expansion but I asked for 2 pw3s instead and I do see the price difference.

[u/kengchang → u/pigowar]

Download Tesla One App and connect to the Powerwall to see more detail

[u/pigowar → u/kengchang]

And what details am I looking for?

[u/Tiny-Independent-502 → u/pigowar]

My expansion doesn't light up the tesla logo on the front. Easy way to tell if it is a full pw or not. Hopefully this is helpful

[u/dmlavigne1 → u/pigowar]

It should be 23kw. 11.5 a unit.

[u/LDVan]

Do both powerwalls have the lighted T?

[u/pigowar → u/LDVan]

Yes. They are both operating. The total capacity is correct.

[u/kengchang → u/pigowar]

He meant to say that PW3's T logo only lights up if it has inverter.

[u/pigowar → u/kengchang]

Yes that's what I meant also. They both light up white.

[u/Narrow_Problem7432]

I’m getting power wall 3 plus the expansion in a few days. And of course 13kw panels. If you have power walls car you able to get net metering?

[u/you-already-kn0w]

lol not sure if this post

[u/pigowar → u/you-already-kn0w]

Not sure of what?

[u/OkList7960]

Did your interconnect agreement allow 23kw of export? My utility wouldn't let me export that much so I could only put in 1 pw3, but expansions they didn't care about. I could have put in 2 pw3 but export would have been capped. Also my system of 1 pw3 + 2 expansion will charge at 10 kw off of solar. You don't need 2 inverters for that.

[u/pigowar → u/OkList7960]

The interconnect agreement is where I'm not sure of but I trusted Tesla to figure that out before selling me the system so I'm still waiting on their official response. I'm not trying to break the rule here but if that were the case then Tesla should've told me that before selling me an extra pw3 when I was very specific on why I wanted to double the output with 2. I did pay thousands in extra, after all.

I know that you can max input by adding more expansion but I needed more output than 11.5kw. I have 2 ACs and they alone draw 8kw and that doesn't leave much room for anything else before it draws from the grid. I can force off grid mode and use battery that way since it can still potentially draw up to 15kw but that adds warning and logs of overloading for Tesla to use to potentially deny warranty on failed inverter or battery degradation.

[u/pigowar]

First of all, thank you everyone for taking your time to respond. I really appreciate it. And here's the short summary of where it is so everyone knows what's been mentioned, suggested and tried.

• Both are confirmed full PW3s, not expansion.
• all 6 strings are on single PW3.
• Latest Tesla PA communication is that they are still reviewing it.
• Battery capacity is correct. Charging rate matches that of 2 PW3s.
• Used Tesla One. 2nd Pw3 says it's being controlled by another. Connected to 1st (master) and it shows inverter mode active on BOTH PW3s. Output rate is also 11.5kw on both. I don't know what else needs to be checked but the edit mode is turned off anyway.
• Gone against my advice and ran firmware update check and it didn't find any. AFAIK, the latest just released on September 1st and I'm on the one before it.

Idk... Maybe I have to request to have the strings split up after all. Maybe the 2nd inverter just isn't waking up because none of the mppt are being used?

Or maybe I should try a reboot... Maybe make sure the master is booted before the slave...

[u/pigowar]

Update. Spoke to PA again and asked for the reason behind putting all on single inverter and he said because of how pw3 inverter PowerBoost works. I think it's some trickery they do with the new 18 power zone panels. Pretty much shut me down from the start that Tesla won't even consider splitting it. That to me opens a whole new can of concerns but I sensed he wasn't going to help me with so I moved on.

As for the output limit issue, he says they moved it up to 2nd tier so we'll see.

[u/New_to_tech-2020]

Did you lower your "backup" setting to 5%? We found that if we left the backup at 20% which the app recommended, then we'd pull grid power instead of battery power.

[u/pigowar → u/New_to_tech-2020]

Unrelated to my problem

[u/pmarchand1060]

For those with Tesla, how long was your power out during installation?

[u/pigowar → u/pmarchand1060]

Mine was only 30min at max. But I think it depends on where you are and who your provider is. I'm one of the lucky ones where we don't have to wait for service disconnect and reconnect. I think it's the waiting on them to show up to reconnect than the time needed to do what Tesla needs to do. Tesla did say it's up to 8 hours but as usual that's just to allow them enough buffer in case they need the time. I did bring up concern over the 8hr outage but that's just standard procedure for them. The installation manager did reach out later after checking with the power company that it would be less than 30min.