AC Coupled Whole-Home Backup

[karamazov]

Hi all - newbie here hoping to get some advice.

I've had solar done before at my last house (in a residential neighborhood) but this time I am looking to DIY. Not only for my own knowledge, but because in my particular atypical situation I can't find a vendor that isn't going to charge me and astronomical amount of money to install a system.

Before we get into requirements, I'll describe my new property and why it poses some problems most people don't have (though I imagine on this forum there are a lot who are in a similar situation). I live on a decently sized rural property. My meter is on the electrical pole, along with a main breaker panel. This breaker panel is not the main breaker for the house - it has a few breakers on it that power my 230v 1HP well pump and 110v chlorinator. The main breaker on the pole also feeds the main breaker in the house, which is about 200 feet in another direction, not near the well.

My requirements are::
- Produce >= 100% of my needs during peak usage (around 40-50kW a day) and sell back to the grid
- Have enough battery backup to keep critical systems online during a multi-day outage (well pump, refrigerator, freezer at night, possibly AC during the day in the summer)

So far I have been working with shopsolarkits.com to get a custom kit built, though I did most of the research myself first. Roughly this is what the system I designed looks like:
- Sol-Ark 15k inverter
- 24x 380w mono PVs
- 4x 100Ah 48v Jakiper server rack batteries

Now given how far apart everything is, neither I nor the vendors I looked at had any solutions for doing a subpanel that holds the breakers for all of the critical loads that wasn't going to be a nightmare and require lots of new cable/trenching. So after reading through the SolArk documentation, it seemed like AC Coupled was the way to go for my situation, as it would allow my inverter to simply provide a micro grid of sorts to my entire home and well. My plan is to build a structure near the electrical pole (my utility provider requires that I have a fused disconnect switch installed 6-10' from the pole anyway) to house all of the equipment, also near where I am going to ground mount the panels. I am going to wire everything up and have an electrician do the hookup to the meter.

But there are a few potential issues that I wanted to get some feedback from someone more experienced in this area:
1. The rep from shopsolarkits said it would be better if I did a subpanel because I could potentially overload the inverter if the grid went down and I had a bunch of load on it. Looking at the specs for the Sol Ark 15k (which can provide 12kW continuous from the batteries), and given that my peak continuous usage is around 9-10kW from the data I have, I didn't see this as a huge risk. Also I didn't read in the inverter documentation anything about this being a risk, it seems to be a fault condition but it didn't say anything about damage.
2. In the Sol-Ark documentation, it mentions requiring a subpanel if you have AFCIs (which I do in my home), but it doesn't say why from what I can tell. If that really is the case then I am going to need to either do a subpanel anyway or replace all of my AFCIs with regular breakers (which I had been thinking about anyway given how annoying those things are, constantly tripping).

Looking forward to hearing some thoughts on this!

 

[Supervstech]

If I’m reading your description right, you have a sub panel at your home. The main panel is at the pole, and has feeders to your house, and the well, etc.

AFCI breakers are the new standard… NEC is trying to make it so EVERY breaker is AFCI… if you have them tripping frequently, they may be overloaded. Many electricians don’t understand the limits to them. They don’t like being on a circuit with several outlets on them. They really like to go to each outlet… so if you have one breaker for all the receptacles in the house, and several outlets are loaded with tvs and various loads, the AFCI acts up. I find it best to have a dedicated circuit to each room minimum…

Anyway, back to the question… the solark should be fine with your sub panel.

 

[karamazov]

If I’m reading your description right, you have a sub panel at your home. The main panel is at the pole, and has feeders to your house, and the well, etc.

AFCI breakers are the new standard… NEC is trying to make it so EVERY breaker is AFCI… if you have them tripping frequently, they may be overloaded. Many electricians don’t understand the limits to them. They don’t like being on a circuit with several outlets on them. They really like to go to each outlet… so if you have one breaker for all the receptacles in the house, and several outlets are loaded with tvs and various loads, the AFCI acts up. I find it best to have a dedicated circuit to each room minimum…

Anyway, back to the question… the solark should be fine with your sub panel.

Thanks for the input!

Just so clarify since you said it would work with my subpanel at the house, my intention is to have it powering the main panel at the pole, so everything at the house and the wellhouse, in case I didn't make that very clear in the original post.

I initially thought they chose the wrong size breakers for the AFCI, but the most troublesome one is a 20A breaker that only powers my microwave...and when it's not happy it will allow my microwave to turn on, but the second I try to cook anything it trips immediately. Oddly enough if I plug it into another outlet (also 20A AFCI), it works fine and never has issues. Probably a bad breaker or something, that's all I can think of.

 

[Supervstech]

Thanks for the input!

Just so clarify since you said it would work with my subpanel at the house, my intention is to have it powering the main panel at the pole, so everything at the house and the wellhouse, in case I didn't make that very clear in the original post.

I initially thought they chose the wrong size breakers for the AFCI, but the most troublesome one is a 20A breaker that only powers my microwave...and when it's not happy it will allow my microwave to turn on, but the second I try to cook anything it trips immediately. Oddly enough if I plug it into another outlet (also 20A AFCI), it works fine and never has issues. Probably a bad breaker or something, that's all I can think of.

Ahh.
That makes it tricky. You want to power the main panel, while powering the pumps and all loads.
Did solark mention why they wanted it installed on a subpanel?

 

[karamazov]

Ahh.
That makes it tricky. You want to power the main panel, while powering the pumps and all loads.
Did solark mention why they wanted it installed on a subpanel?

They did not, it just said that you should use a subpanel in the case that you have AFCIs. I reached out to their support but haven't heard back yet, hopefully they can clarify.

 

[karamazov]

In case anyone else comes across this thread and is in a similar situation, here's what the rep from Sol-Ark told me:

The inverter has built in protection to prevent damage from an overload. If the system ever was to overload (furnace), the inverter would shut down and then reset itself after about 2 minutes. This prevents damage from happening to the inverter and would allow you to shut off the load at the breaker panel.

The reference in the manual you are referring to regarding subpanels and AFCI/GFCI breakers is in contrast to multi-switch transfer switches not whole home panels vs. subpanels. Using your whole homes panel is totally fine. With the 15k, you do no need to install a subpanel as long as when the grid is down you manage your loads to prevent overloads (or turn them off after an overload occurs).