Need Advice: Expanding My Solar System Due to EV Commute

[generalmilk]

I recently joined the CA solar installation trend and opted for the NEM2 with a 6.12kw SolarEdge system. After two months, I'm realizing I need more capacity. My wife and I have been working from home, and our system was based on past consumption. However, I've started commuting with an EV, and our current setup won't suffice.

We live near the SF fog line, impacting our solar production. Data from the past two months indicates a yearly production of about 10mwh. Last year, our consumption was 7.2mwh, but with the EV commute, I anticipate 12-13 mwh. It's frustrating to need an expansion so soon.

I've considered the following options to add just 1kw:

1. Expanding with the Original Solar Company: It is likely to cost a lot and increase my ROI, since the inverter (5kw) needs to be replaced. My existing system was about $2.8/w, not too bad at a time that everyone and their dogs wanted solar installation, but no way I can get such rate in expansion.
2. DIY with SolarEdge: This involves adding 3 panels and upgrading to a 6kw inverter. The downside is the inverter cost and potential loss of the installation company's warranty.
3. DIY with Enphase iq8m: Here, I'd add 3 panels and the necessary Enphase components. This might allow me to integrate the outputs into a single monitoring system like in this post. This method might be cost-effective, future-ready due to the microinverters, and could retain the original system's warranty (if the company remains in business). However, it might be challenging for a DIY approach, so really need some advice on how to do it.

Any suggestions or other options? I'd appreciate any advice!

 

[BillG]

If you engage your install contractor to expand the system they may want to pull a permit. Pulling a permit may (I am not 100% sure yet how that works) bump you into NEM 3.0 which you really want to avoid...
Adding 3 panels to a SE system and swapping the inverter is a piece of cake, anyone could do that. PG&E will be none the wiser...

I did a job last year where we added a ginormous 66 panel Solar Edge ground mount to an existing small Enphase NEM 1.0 enphase system. It was pretty complex and involved multiple sub panels and an MPU. As a contractor, we absolutely do NOT want to touch a system installed by others so we took great care in maintaining a clear separation. I was not aware there were monitoring solutions that combined SE/Enphase systems. To me that is needlessly increasing complexity and failure points by orders of magnitude.

 

[MichaelK]

How are your panels oriented right now? All facing South? One option is to add parallel arrays facing in different directions, say East, or West. This will let you continue to use the inverter you have right now. All the arrays need to be the same voltage (within 5%).

That South facing array won't be anything more than 5-10% output at 7am, when the sun is almost due East. But, an East facing array will be. As the sun swings across the sky, at ~10am, the East and South arrays will both be at ~50%. As the sun reaches South, the output of the East array starts dropping towards zero, whereas the West array starts making more power. Finally, as the sun reaches sunset, the Western array will be at full output, while the East and South are close to zero.

So, you more or less produce about the same number of instantaneous watts, but more total watthours over the course of the whole day.

 

[generalmilk]

If you engage your install contractor to expand the system they may want to pull a permit. Pulling a permit may (I am not 100% sure yet how that works) bump you into NEM 3.0 which you really want to avoid...
Adding 3 panels to a SE system and swapping the inverter is a piece of cake, anyone could do that. PG&E will be none the wiser...

I did a job last year where we added a ginormous 66 panel Solar Edge ground mount to an existing small Enphase NEM 1.0 enphase system. It was pretty complex and involved multiple sub panels and an MPU. As a contractor, we absolutely do NOT want to touch a system installed by others so we took great care in maintaining a clear separation. I was not aware there were monitoring solutions that combined SE/Enphase systems. To me that is needlessly increasing complexity and failure points by orders of magnitude.

Thank you Bill!
You just reminded me that I can just add 3 panels without replacing the inverter, it will likely still bring in some additional production. My question is since the system is installed by a contractor, I don't even know the string configuration, can I still do it without them voiding the service warranty?

 

[generalmilk]

How are your panels oriented right now? All facing South? One option is to add parallel arrays facing in different directions, say East, or West. This will let you continue to use the inverter you have right now. All the arrays need to be the same voltage (within 5%).

That South facing array won't be anything more than 5-10% output at 7am, when the sun is almost due East. But, an East facing array will be. As the sun swings across the sky, at ~10am, the East and South arrays will both be at ~50%. As the sun reaches South, the output of the East array starts dropping towards zero, whereas the West array starts making more power. Finally, as the sun reaches sunset, the Western array will be at full output, while the East and South are close to zero.

So, you more or less produce about the same number of instantaneous watts, but more total watthours over the course of the whole day.

Thank you for your suggestion. I attached a photo of my roof. The house is facing south and south west. I added a north arrow on the picture. Unfortunately our roof doesn’t have the best layout, so we used most spaces on south, east and west side. I can barely find 3 spots on the south side as illustrated, that’s where I intended to install the new panels. The north side is rather empty, but it’s north and there is a slope behind the backyard with tall trees casting shade in the morning.

Our roof is a bit flatter, I had clipping (6.12kw panels + 5kw inv) for about 3 hours on a sunny late July day, so I guess all the panels are producing in the noon.

 

[BillG]

Thank you Bill!
You just reminded me that I can just add 3 panels without replacing the inverter, it will likely still bring in some additional production. My question is since the system is installed by a contractor, I don't even know the string configuration, can I still do it without them voiding the service warranty?

Similar to car warranties, they would have to prove your addition caused the failure. I dont think they can blanket say "AH, you touched it warranty void" . The only
SE has 25 opti's max per string. if you have 22 panels or less, you can add 3 no problem. If you have to have another string, that just means you have to run another home run to the inverter.

 

[BillG]

Whoever installed that left excess rail all over the place. Slide the panels over and bolt on some more mods. I think you could get 2 more on your East elevation, 2 on your south and 2 more on the West; all on the existing rail!. AND it would look alot better... For the safety Sallies, I'm aware and dont care yhat there may have been set back requirements for fire dept roof destruction access.

 

[400bird]

How are your panels oriented right now? All facing South? One option is to add parallel arrays facing in different directions, say East, or West. This will let you continue to use the inverter you have right now. All the arrays need to be the same voltage (within 5%).

Not with a Solar Edge system. Everything panel has an MPPT.

My question is since the system is installed by a contractor, I don't even know the string configuration, can I still do it without them voiding the service warranty?

You might be able to see the string config in the Solar Edge monitoring portal, but your installer might not have given you that access level. I can see it in mine.

Whoever installed that left excess rail all over the place. Slide the panels over and bolt on some more mods. I think you could get 2 more on your East elevation, 2 on your south and 2 more on the West; all on the existing rail!. AND it would look alot better...

I halfway wrote this response, then saw yours. 100% agree. Even the setbacks don't look bad. He'll just be too close to both sides of the south facing eve/hip.

My question is since the system is installed by a contractor, I don't even know the string configuration, can I still do it without them voiding the service warranty?

Legally, they'd have to prove you caused the failure. But be ready for them to ignore that and say

"AH, you touched it warranty void"

? sorry, I couldn't help myself.

Thank you for your suggestion. I attached a photo of my roof. The house is facing south and south west. I added a north arrow on the picture.

Those panels on the northwest aren't going to do much for you, even less come winter.

 

[generalmilk]

Not with a Solar Edge system. Everything panel has an MPPT.


You might be able to see the string config in the Solar Edge monitoring portal, but your installer might not have given you that access level. I can see it in mine.

I halfway wrote this response, then saw yours. 100% agree. Even the setbacks don't look bad. He'll just be too close to both sides of the south facing eve/hip.


Legally, they'd have to prove you caused the failure. But be ready for them to ignore that and say

? sorry, I couldn't help myself.


Those panels on the northwest aren't going to do much for you, even less come winter.

Thank you everyone, these are all great suggestions!

I really like the sliding idea!! Unfortunately I don't have the layout access and the installer refused to give it to me.

But these are minor issues now. Yesterday I just found out our approval from PGE was for a much smaller sized system than what we have!

It was for 16*360 and SE3800 which was an old design, and was later revised to 17*360 and SE5000 on 03/29. But it seems the installer, Better Earth never bothered to make the change in the application. The submission confirmation was on 03/31. I'm really mad at them now!

 

[generalmilk]

Similar to car warranties, they would have to prove your addition caused the failure. I dont think they can blanket say "AH, you touched it warranty void" . The only
SE has 25 opti's max per string. if you have 22 panels or less, you can add 3 no problem. If you have to have another string, that just means you have to run another home run to the inverter.

It seems SE5000 has a max input voltage of 480 per string, and each of my 360 panel has a voltage of 40.8. I thought that means I can only put 11 panels on one string?
Never mind, from the picture it is clearly single string.

 

[Hedges]

I think Solar Edge optimizers output lower voltage than PV panel and you can have more panels in series, up to about 25, without exceeding max voltage of inverter. But double check that.

I think with Solar Edge you can also make an array with two strings in parallel, e.g. 11s2p.
Ideally those two strings of different orientations. Panels in a given string normally all one orientation, but Solar Edge optimizer allows at least some variation in orientation.

Do you already have permission to operate from PG&E?

 

[generalmilk]

I think Solar Edge optimizers output lower voltage than PV panel and you can have more panels in series, up to about 25, without exceeding max voltage of inverter. But double check that.

I think with Solar Edge you can also make an array with two strings in parallel, e.g. 11s2p.
Ideally those two strings of different orientations. Panels in a given string normally all one orientation, but Solar Edge optimizer allows at least some variation in orientation.

Do you already have permission to operate from PG&E?

Thanks Hedges! I do, and my system has been working for 2 months

 

[Hedges]

In that case, adding panels/strings may go unnoticed. If your export ever exceeded 3.8 kW they could notice, but only if they programmed to catch it.

 

[generalmilk]

In that case, adding panels/strings may go unnoticed. If your export ever exceeded 3.8 kW they could notice, but only if they programmed to catch it.

Well, my system is 5kw, they may already exported more than 3.8kw sometime in July. I feel my nem2 status is even in jeopardy

 

[JBertok]

I like the suggestion to slide the panels on the existing rails on the Southwest and Southeast-facing sections to add 3 more. There appears to be plenty of rail up there, maybe it was a rushed job, looks horrid but works out good in this case. You can add a total of 5 more if 2 are added to the Northwest roof too, albeit with lesser daily output for those.
Using the existing extra rails means you don't have to alter the conduit, and it keeps the parts list low. It might be necessary to pull another pair of conductors through the conduit if splitting the string becomes necessary.

Need to identify the model of the panels, optimizers, rails, panel-mount for rails, and rail mounting hardware for the optimizers.
Also need to identify if this is two or one string currently, and which panels are on what string if already 2, so the calculations can be done for adding more. With only 17 panels and the big chunk of Northwest facing modules, I'm going to guess it's all one string.
And, need to find out if you can get the inverter into optimizer pairing mode, or if it's locked out.
(Keep track of the serial numbers of the new optimizers into which position they are installed; you'll need that later for the App.)

As an additional benefit, you'll be inspecting the existing work done by the installation company and may decide, based on what you find, that you never want them near your home again. It happens...
Far as warranty goes, the equipment is unlikely to have issues, and even if something fails you might be able to pursue manufacturer warranty or for even less hassle just purchase a replacement (panel, optimizer, etc.) The inverter is the only expensive item. The main thing I'd be focused on for warranty is stuff caused by the installation itself - roof leaks, penetration problems, conduit, electric junctions, etc.

 

[zanydroid]

I think adding 3 panels onto an existing string where there's another cook involved (your solar company) is asking for complications. I prefer to keep things cleanly separated to avoid finger pointing / having to escalate to legal means, and that is how I did my DIY expansion this year. Did not reuse anything. Old system was HoyMiles micros, new system is also HoyMiles but completely separate monitoring, rails, conduit, etc.

3 panels is most likely below SolarEdge official minimum; this would be determined by the minimum string voltage and maximum boost voltage of after optimizers. As well as the voltage of the strings when optimizers are in shutdown mode. The minimum is in the specs for the optimizer. I was looking at it out of curiousity last week and I believe it's 5 per string.

My latest obsession is believing that no MLPE >> microinverters >> optimizers with the current state of the industry. Optimizers are too proprietary and they have a lot of lag to make up vs microinverters. Of course nothing beats "bare" panels, which in the US means RSD.

3 panels is also below the official minimum of a lot of string inverters. There are ways to use hacked optimizers to boost the voltage, but this is a very artisanal approach that is likely to cause long term maintenance issues (what if the optimizers fail and you can't replace them? what if you go senile and can't explain how to fix it?).

3 panels is fine for microinverters (it scales down to individual panels on individual roof planes, the bottleneck at that point is the extremely high labor and ugliness of wiring in such small arrays), and you can save by using multi-port non-Enphase microinverters.

 

[zanydroid]

Well, my system is 5kw, they may already exported more than 3.8kw sometime in July. I feel my nem2 status is even in jeopardy

I don't know how the 3.8kW crept in. I see you have a 5 kW-AC system, and if you are overpaneled as you should be PG&E has you down for 5kW-AC export.

 

[400bird]

But these are minor issues now. Yesterday I just found out our approval from PGE was for a much smaller sized system than what we have!

Ouch? That's rough.

It was for 16*360 and SE3800 which was an old design, and was later revised to 17*360 and SE5000 on 03/29. But it seems the installer, Better Earth never bothered to make the change in the application. The submission confirmation was on 03/31. I'm really mad at them now!

The giant paperwork error along with the stupid looking rails makes me think this isn't a top notch solar installer, but that's just my opinion.

 

[Hedges]

The stupid looking rails aren't so bad if you can fit another panel. Unmount panels and slide rails to preferred location. Might be a rather long cantelever.
I wouldn't care about panels hanging over both sides of a ridge when there is an entire face available for walking.

Does Solar Edge have a limited export feature using CT?
That could let you sit at 3.8 kW all day long. Additional power would be collected if you had loads.

 

[zanydroid]

The giant paperwork error along with the stupid looking rails makes me think this isn't a top notch solar installer, but that's just my opinion.

Is there a correction possible with PG&E? I thought there was a process in place for that. What did the installer offer as compensation? They may also know how to correct. You could go straight to CSLB or trigger arbitration but it’s probably smarter to try to be cooperative

Also note the DC AC ratio on the original application is past the standard ratio. I thought PG&E app and engineering review was supposed to have a shot at catching it.