Exports to grid being capped at 4kw

[jgbaum]

I have a new 16.25kw and 2PW+ installation. We got PTO last week and started exporting our excess energy to the grid, sometimes at a rate of 10kw. Since Friday, however, I noticed that our production dropped at around 12:30pm when our powerwalls filled up (see plot below). Then I noticed that if I turned on equipment that drew a lot of power, our production would match that but go no higher. Looking deeper into it, when I go to the 'summary' screen on my gateway, I see a 'site export limit' of 4kw (screenshot below). Whenever we have excess electricity, we can no longer export anything over 4kw, which is frustrating. This seems to be a 'feature' that is supposed to be enabled only in Hawaii and Australia, and I'm not in either. I'm not sure how this happened and Tesla support has so far not fixed the issue, but I'm hoping they figure it out before I lose out on too much of my energy credits.

Just thought I'd share here in case anyone noted similar issues (or has a fix).

 

[arnolddeleon]

Hmm, is the information also correct in that your electrical panel 100A? Do you have a gateway or are you using the new backup switch with the PW+? Can you share your usage data as well?

I believe one of the new configurations that is supported with the PW+ is the ability to avoid a main panel upgrade. The tradeoff is you are potentially limited in power exports. 4 kW is suspiciously close to 20% of 100A. There is usually a 20% backfeed limit for a panel. Is the system correctly reporting your grid usage?

I suspect there is a misconfigured CT (current transducer) because it looks like system thinks the main panel is under full load and curtailing solar.

 

[jgbaum]

Thanks for the feedback @arnolddeleon. My main was upgraded to 200A, but Tesla inexplicably installed a 100A sub panel as part of my ‘whole home backup’. I have another thread on that here that includes the setup details: 'whole home backup' confusion

 

[arnolddeleon]

After looking at the other thread my one word response is yikes!

It looks to me like you have a configuration that was intended for a non-upgraded service/panel but it doesn't make sense for the configuration you actually have. All your generation is on a dedicated panel (built-in to the gateway). This makes it much easier to understand. You are limited to 100A of load because of the 100A breaker to your distribution panel despite the fact the you have 200A total theoretically between the grid and the your PW+. There is no reason to limit the output of the PW+ because there are no buses it can overload if it was pushing out 100A. The backup gateway is rated for 200A. I don't see any unprotected conductors or buses that could be exposed to current above its ratings between the gateway and main service panel and between the gateway and your distribution panel. I suppose there could be some odd code or local requirements, @Vines is the expert there.

The short version is I think Tesla enabled PCS on your system and you don't really need. The 100A breaker and possible undersized wiring is a different but related kettle of fish.

 

[jgbaum]

I posted this question on Reddit as well and got a few potential clues. The latest theory is it could be related to a misconfiguration of my CTs...I do not really know what CTs are, but I do see a couple of warnings on the 'cts' page when I login to the PW (screenshots below). Could this be a clue, or just a red herring? Any idea what the correct settings would be?

 

[bryan995]

FYI in installer mode there is an option to set an export limit. Not saying you should adjust it, but that is likely where it was set.

 

[jgbaum]

Thanks @bryan995. That was the first setting I looked at, but it was already disabled...

 

[jboy210]

I posted this question on Reddit as well and got a few potential clues. The latest theory is it could be related to a misconfiguration of my CTs...I do not really know what CTs are, but I do see a couple of warnings on the 'cts' page when I login to the PW (screenshots below). Could this be a clue, or just a red herring? Any idea what the correct settings would be?


View attachment 707374
View attachment 707375

CT = Current Transducer. It is a circular sensor that is placed around a wire and measures the amount of current passing through the wire. If they are not installed correctly you can have missing or incorrect direction current flows reported. And this means everything based on these current flows is incorrect. So, given the warning, you have to wonder how valid your numbers are. I would contact the installer and let them know about the warning and resultant numbers. They can often fix CTs issues quickly.

 

[cwied]

The warning specifically says “if not using the single solar CT option”, and that is in fact what the case is here. I wouldn’t think this warning is a problem, or that there is a CT problem, since the solar production curves look reasonable.

 

[jgbaum]

A Tesla electrician came by today and spoke to their internal tech support about this issue. Apparently my account was still stuck in PTO in their system for some reason, so exports were being capped. Supposedly they've requested to pull my house from that list and I should be exporting tons of clean energy any day now...

 

[KHYE]

A Tesla electrician came by today and spoke to their internal tech support about this issue. Apparently my account was still stuck in PTO in their system for some reason, so exports were being capped. Supposedly they've requested to pull my house from that list and I should be exporting tons of clean energy any day now...

Thanks for sharing your issues and posting the follow ups. I will be getting new system and good to watch out on this.

 

[charlesj]

20 days to get someplace? A whole bunch of non exported energy lost.

 

[jgbaum]

20 days to get someplace? A whole bunch of non exported energy lost.

Yes, I figure I've lost 400kwh or more that could have been exported. Then again I've only paid them $100 to this point .

 

[jgbaum]

It turns out they still haven't figured out the issue...latest update is that they think I potentially have settings applied to my account that don't match the product(s) that I have installed. So, I'm still capped for now and waiting on them to figure it out...

 

[charlesj]

It turns out they still haven't figured out the issue...latest update is that they think I potentially have settings applied to my account that don't match the product(s) that I have installed. So, I'm still capped for now and waiting on them to figure it out...

That's crazy stuff.

 

[jgbaum]

OK so 3 months after I filed the ticket and after many times telling me it was resolved (it wasn’t), I finally got an answer that makes sense. Unfortunately it also makes me furious. Apparently they placed an export limit on my system to comply with requirements from SDG&E. Does that sound right? Anyone else in San Diego being capped like this?

 

[gpez]

OK so 3 months after I filed the ticket and after many times telling me it was resolved (it wasn’t), I finally got an answer that makes sense. Unfortunately it also makes me furious. Apparently they placed an export limit on my system to comply with requirements from SDG&E. Does that sound right? Anyone else in San Diego being capped like this?

Not SDG&E specific but it happens that local transformer capacity and load projections limit how much power can be exported. You may be able to get a more complete answer from SDG&E about why the limit is there and if it's due to capacity concerns on the local lines and transformers see if they have plans to upgrade.

 

[charlesj]

I would understand if there were a limit on exporting peak power that may be an issue but that is far from limiting the overall kWh in a day or month one can send to the grid. That would be pure greed on their part and even that doesn't sound right as they sell your extra at retail and you are netted at the end of cycle.
Your neighbors would be the first customers to get the extra which may be before a transformer.

 

[skepticcyclist]

Do you also have battery backup? If so your best option at this point would be to put it in "Self Powered" mode to get the most out of your solar.

 

[RandyS]

@jgbaum

I have about 12 kW of solar in the SDG&E area (and just retired after working for them for 36 years) and I've never heard of SDG&E putting this type of limit on the amount you can export out of your solar system. There has to be another explanation for it...