SE Inverter question/option

[k-mal_808]

Aloha TMC folks, so long overall story here but I’ll try and keep short and to the point. I originally ordered an 8.16kw system, but due to roof size constraints, had to drop 3 panels and wound up with a 7.14kw system. Original plans called for the SE7600 inverter, but they installed a SE6000. Now Tesla wants to come back today to swap the 6000 for the 7600. My question is which inverter, if you could choose, would you prefer for the 7.14kw system? The reason they want to swap if anyone is curios....they did a revision for the building permit after install and forgot the revise the inverter, so my approved permit has the 7600 and my utility interconnect has a 6000. I guess the easier revision now is the interconnect being that I’m still in the PTO process. Any thoughts? I need to let them know ASAP as they have a tech scheduled this afternoon. My initial thoughts are to keep the 6000 as I have panels facing all four directions and will most likely never see the full 7.14kwp. TIA.

 

[Redhill_qik]

The SE7600 (7.6kW) will guarantee that you have no clipping and get the full amount from the solar panels, but the amount of loss from the SE7000 (6.0kW) is likely to very small over the entire year with clipping only happening a few days year when you optimal solar conditions and since you said that you have panels aligned with all four directions the panels won't hit the optimal conditions at the same time.

Personally, I would let them go ahead and do the swap as you will have more margin and will be able to get the inspection done sooner.

 

[BrettS]

Yeah, it’s a tough call. Obviously the bigger inverter would guarantee that you wouldn’t have any clipping, but like you said, you’re probably unlikely to see any clipping with the smaller inverter anyway. It’s also my understanding that the inverters are slightly more efficient at higher loads, so theoretically the smaller inverter might be slightly more efficient than the larger one, but again it’s not really going to make a significant difference.

The smaller inverter is cheaper (and they won’t have to pay someone to go out and replace it) so will they give you a credit to keep the smaller one? Additionally if you want to purchase the 25 year warranty extension from SolarEdge I believe that will be slightly cheaper for the smaller inverter as well.

 

[k-mal_808]

Ran the PVWatts calcs with the two different DC:AC ratios and the smaller inverter wins out by a very small margin on yearly output. That coupled with the fact that I already have it hardwired with monitoring set up, and customized to my liking, has me leaning towards keeping it as is. I'll ask about a potential credit for keeping as is. Thanks for the feedback.

Edit: asked about the credit and as I suspected, not gonna happen. Told them I'd let them know which size today or tomorrow.

 

[getakey]

no credit? They quoted system with larger inverter and charged you that price? Furthermore, by keeping smaller inverter they are saving labor to swap them. I'd push back

 

[gpez]

@k-mal_808 do you know which "trim" you were supposed to get and what "trim" you received? SolarEdge has a few different variants on both the SE7600 and SE6000, with I believe the "H" model (SE7600H / SE6000H) being the high end. The "H" models have improved efficiency over the "A" model (99.0% vs 97.5%). SolarEdge Single Phase Inverter with HD-Wave Technology | SolarEdge I'll ignore the trim question for now but if you were supposed to get an H but didn't or got an H and weren't supposed to I'd index on keeping the H model regardless. The H may be the only one they sell, not sure though as my install used IQ6 micros.

All else being equal: as you noted you'd likely never hit the full 7.14kW with your panel set up and likely will actually get more efficiency out of an undersized inverter. That said, I'd absolutely ask for (demand) a credit if you paid for a SE7600 as they retail ~$300 less than the SE6000.

The other thing to consider is if you have any near-term plans to add more panels. If you do then you'd likely need to upgrade your inverter at that time so installing the larger one now gives you that room.

EDIT: Here are listings for the SE6000H vs SE6000A so you can see the difference.
SolarEdge SE6000A-US Single Phase Inverter SE6000A
SolarEdge HD Wave SE6000H-US Inverter - Wholesale Price SE6000H

Also interesting to note that the max DC power input for the SE6000A is 7,500w but the SE6000H is 9,300W.

 

[BrettS]

no credit? They quoted system with larger inverter and charged you that price? Furthermore, by keeping smaller inverter they are saving labor to swap them. I'd push back

I agree that it makes sense to get a bit of a credit, but I also felt it was a bit of a long shot. Keep in mind that Tesla quotes a whole system price. They don’t really quote specific equipment or inverters, so it would be hard to argue that you were promised a specific inverter.

In the end it’s maybe a $200 difference between the two inverters. It would be nice if they would give him a $200 credit, but in the grand scheme of things it’s what, like 1% of the system cost?

It was worth asking for, but I’m not sure it’s really worth pushing.

 

[gpez]

I agree that it makes sense to get a bit of a credit, but I also felt it was a bit of a long shot. Keep in mind that Tesla quotes a whole system price. They don’t really quote specific equipment or inverters, so it would be hard to argue that you were promised a specific inverter.

That's good info. There's no bill of materials with the quote? The statement the OP made around "original plans" made it sound like it was part of the contract and quote.

 

[k-mal_808]

I agree that it makes sense to get a bit of a credit, but I also felt it was a bit of a long shot. Keep in mind that Tesla quotes a whole system price. They don’t really quote specific equipment or inverters, so it would be hard to argue that you were promised a specific inverter.

In the end it’s maybe a $200 difference between the two inverters. It would be nice if they would give him a $200 credit, but in the grand scheme of things it’s what, like 1% of the system cost?

It was worth asking for, but I’m not sure it’s really worth pushing.

Agree on all points. I asked, they said no, I'll leave it that. Like you said, they don't have a specific inverter model or size in the contract, so I don't have much to argue. Another point worth mentioning is that keeping the 6000 would keep my PTO on track to happen in the next week-ish, whereas changing to the 7600 would require a revision that would delay a few weeks. They would then retroactively submit a revision for the building permit(which is already approved and closed, lol). Path of least resistance is leave it as is, but I wanted to be sure I wasn't missing anything before committing.

 

[k-mal_808]

That's good info. There's no bill of materials with the quote? The statement the OP made around "original plans" made it sound like it was part of the contract and quote.

Original plans submitted to the building department for the permit. Not on my contract. The contract has the generic inverter and equipment verbiage.

 

[k-mal_808]

@k-mal_808 do you know which "trim" you were supposed to get and what "trim" you received? SolarEdge has a few different variants on both the SE7600 and SE6000, with I believe the "H" model (SE7600H / SE6000H) being the high end. The "H" models have improved efficiency over the "A" model (99.0% vs 97.5%). SolarEdge Single Phase Inverter with HD-Wave Technology | SolarEdge I'll ignore the trim question for now but if you were supposed to get an H but didn't or got an H and weren't supposed to I'd index on keeping the H model regardless. The H may be the only one they sell, not sure though as my install used IQ6 micros.

All else being equal: as you noted you'd likely never hit the full 7.14kW with your panel set up and likely will actually get more efficiency out of an undersized inverter. That said, I'd absolutely ask for (demand) a credit if you paid for a SE7600 as they retail ~$300 less than the SE6000.

The other thing to consider is if you have any near-term plans to add more panels. If you do then you'd likely need to upgrade your inverter at that time so installing the larger one now gives you that room.

EDIT: Here are listings for the SE6000H vs SE6000A so you can see the difference.
SolarEdge SE6000A-US Single Phase Inverter SE6000A
SolarEdge HD Wave SE6000H-US Inverter - Wholesale Price SE6000H

Also interesting to note that the max DC power input for the SE6000A is 7,500w but the SE6000H is 9,300W.

Sorry reading out of order. Both models in question are the H models. Unfortunaly I have zero room for more panels, hence having to downgrade from 8.16kw to 7.14kw due to lack of roof space.

 

[gpez]

Sorry reading out of order. Both models in question are the H models. Unfortunaly I have zero room for more panels, hence having to downgrade from 8.16kw to 7.14kw due to lack of roof space.

Ah - totally skipped the part about roof space in your OP, my bad.

If it were me I'd stick with the SE6000H. Less hassle, likely better anyway in the long run.