Need help : want to ac couple to a Enphase grid tied.

[629658]

Wow, OK. Do they do this for all projects (seems ridiculously unscalable), or is this specific to using SolArk / ESS that they're not used to?

I don't think this kind of adjustability is available in microinverters.

One other thing unique to batteries is that theoretically the curve can be adjusted so that they absorb active power from the grid in some conditions. Although unless they're also going to give you the electricity for free at those times, this feels like something that will piss off a lot of people.

I modified my old interconnection agreement to be able to grid charge my ESS. Which is what I do at times. We elect to be on TOU. It is a beautiful thing with Solar and ESS. In winter I charge my ESS early AM for usually 2 cents per kWh. Then on batteries the rest of the 24 hr period. In summer I’ll charge again in early AM and keep them at 100% until say 0900 at 2-3 cents per kWh. Then all my PV production will be grid sold at 12-20 cents per kWh. It makes our bill a credit balance each month that we carry into the fall.

 

[zanydroid]

I modified my old interconnection agreement to be able to grid charge my ESS. Which is what I do at times. We elect to be on TOU. It is a beautiful thing with Solar and ESS. In winter I charge my ESS early AM for usually 2 cents per kWh. Then on batteries the rest of the 24 hr period. In summer I’ll charge again in early AM and keep them at 100% until say 0900 at 2-3 cents per kWh. Then all my PV production will be grid sold at 12-20 cents per kWh. It makes our bill a credit balance each month that we carry into the fall.

I’m sure I surprised them by applying for 95kWh.

OK, the fact that you were at 95kWh probably put you on the extra scrutiny list :laugh: With that size battery if the SolArk is misconfigured it will persist in dumping something bad to the grid for a couple hours.

That sounds like a pretty permissive ESS policy, but you also seem to be directly exposed to the spot wholesale price.

 

[zanydroid]

I get battery storage for ...

Didn't have a chance to read the link, but I think they also subsidize in areas subject to aggressive Public Safety Power Shutoff

 

[629658]

Apologies for making this confusing, probably cause it's how I feel right now! Yes I suppose I am treating this like an off grid capable inverter as well. yes having a bit more capability down the road seems like a better idea to me. I would prefer to go off grid, but I'm poor. Does it make much sense to choose an anemic inverter that can be paralleled, then buy a second one in a year or so? So with the lesser wattage inverters they would supply all they can, and if not adequate for the load than the grid would supply the rest that is required correct?
Battery topic. I'm in the middle of a dyi Eve cell battery. BC I'm cheap.
Not sure if I need to be permitted, quite sure the utility company would rather I didn't do any of this!
Thanks for your help and hanging in there with me! Eric R.

You could use them here as no one was interested or had any knowledge about batteries. They went through my inverter with a fine tooth comb. I can’t say enough about how the Sol Ark saved me as it ticked every box and gave them zero opportunity to deny it.
I’m sure there are other brands that work equally well. I know Sol Ark is more expensive but if you consider the 30% federal tax credit it makes it palatable. If you can’t go it I get it. You do what you can. One thing to consider what ever brand you choose is if you go small and/or cheap that money is gone when you upgrade. If you buy better now it will at least keep you in the game down the road.

 

[zanydroid]

Does it make much sense to choose an anemic inverter that can be paralleled, then buy a second one in a year or so? So with the lesser wattage inverters they would supply all they can, and if not adequate for the load than the grid would supply the rest that is required correct?

Lower end inverters usually cannot do grid / generator assist. That is a higher end feature, that intrinsically requires more hardware in the inverters.

Hard to say whether you want to get an anemic inverter. Once you buy into an inverter, you can only parallel more of the same kind. If you parallel across types of inverters, you are back to AC coupling, with all the issues discussed so far.

The higher end inverters are all going to be like 2x the cost of Megarevos etc. They'll probably get cheaper eventually.

I expect UL listed hybrid inverter and battery prices to plummet in the next few years, so not clear how much an investment in SolArk etc will hold up.

If you go with a weaker/lower end inverter you need to compensate for that with design skills, skills at asking questions properly and translating them properly to execution, or skills at reducing the scope of your requirements.

Probably the easiest system is an off-grid AIO, unpermitted, that powers / offsets a subset of your loads without grid interaction of any sort. And you pick loads that are easier to drive.

 

[629658]

OK, the fact that you were at 95kWh probably put you on the extra scrutiny list :laugh: With that size battery if the SolArk is misconfigured it will persist in dumping something bad to the grid for a couple hours.

That sounds like a pretty permissive ESS policy, but you also seem to be directly exposed to the spot wholesale price.

I’m sure the self install didn’t help either. I was notified Monday that it was approved and check was cut. A lot of things fell our way on this project. We have been solar customers of theirs for 9 yrs. We have been in contact with several at the utility for years now so that did help

 

[629658]

We have a great POCO. Very solar friendly and willing to help with all the paperwork. I cannot say enough good about Ameren Illinois.

 

[X propane]

The higher end inverters are all going to be like 2x the cost of Megarevos etc. They'll probably get cheaper eventually.

Darn I was thinking the Megarevo, might be a decent option for my current needs.

 

[Hedges]

Didn't have a chance to read the link, but I think they also subsidize in areas subject to aggressive Public Safety Power Shutoff

Two safety shutdowns and one additional requirement (either poverty/health, or have a well pump) to get the $1000/kWh figure.

https://www.cpuc.ca.gov/-/media/cpuc-website/files/uploadedfiles/cpucwebsite/content/news_room/newsupdates/2020/residential-equity-and-equity-resiliency-matrix.pdf

 

[zanydroid]

Darn I was thinking the Megarevo, might be a decent option for my current needs.

There is are one or two threads for it, have you asked there?

IMO it’s a bit underbaked but maybe it will get there.

I don’t trust EG4/Megarevo to get the California certifications so it has dropped off my radar.

 

[629658]

Two safety shutdowns and one additional requirement (either poverty/health, or have a well pump) to get the $1000/kWh figure.

https://www.cpuc.ca.gov/-/media/cpuc-website/files/uploadedfiles/cpucwebsite/content/news_room/newsupdates/2020/residential-equity-and-equity-resiliency-matrix.pdf

Heck we have a well. And I thought $300 was too much. It is a great rebate. I have $1000.00 out of pocket for my 95kWh ESS. I also get to claim the 30% FTC so you do the math. I was offered another $300 per kWh of inverter but declined that one as it would have triggered a new less favorable interconnection agreement. Our inverter got classified as a replacement for end of life GT inverter so we get to keep our 9 yo agreement.

 

[Hedges]

"A fool and his money are soon parted"

And just who is the fool, now?!

 

[629658]

"A fool and his money are soon parted"

And just who is the fool, now?!

Honestly I feel a little guilty. I added up all we have spent over the past 10 years on solar about $90k give or take. Out of pocket less than $20k. I pay a lot in taxes but…

On the plus side we are now almost totally energy independent. Haven’t been on the grid at all in almost 2 weeks.

 

[Hedges]

My father avoided accepting any benefits he was entitled to from the government, understanding they were bankrupt. Decades ago.
I've paid some fat tax bills (more zeros than you would likely believe), so when I do get a partial rebate I feel no guilt.
Just cut another couple checks a few days ago, balance due is like my starting salary years ago, total taxes paid is a princely sum.
I am going to need a decent amount of retirement income for various utilities, taxes, insurance. Other than that we can be frugal.

 

[wheisenburg]

Auto transformer usage in the USA will not pass inspection. Many threads on this subject. Those that advocate their use in these forums 100% of the time fail to mention this to the newbies. So they buy the stuff install it and then fail inspection and lose the money they spent. Sad but happens all the time.

Interesting. Guess what Enphase has inside their System Controller 2 to generate split phase from their 240 Volt inverters? That's right, an autotransformer. It is certified. Maybe because they have done the integration and testing work.

 

[Ampster]

Auto transformer usage in the USA will not pass inspection.

I agree generally for standalone operation, however when inside devices like the above mentioned Enphase System Controller or an Low freguency inverter which have UL listings they are used a lot and pass inspection based on the devices UL listing.