Non backfeed but Grid tied?

[eggsnbak0n]

So I'm in the early stages of planning my solar / battery for a custom lake home build. My power on the lake is extremely cheap .10 kw/h Along with the cheap power is that the solar generation is most likely going to be limited, so here is my plan and question:

I want to generate as much power as possible that remains cost effective without back feeding into the grid, which simultaneously reducing the power needed from said grid due to solar generation.

The home will have 2 200Amp "mains" installed. So there is a possibility that 1 panel could be connected to the batteries while the other is grid tied only in my assumption. Was thinking one panel for essentials and the second panel for non essentials.

What's the best inverters for this situation? I was looking at the 6000XP indoor with a pair of EG4 batteries, however I'm not sure this can load balance with a grid without back feeding?

Any suggestions would be appreciated. Thank you.

 

[Hedges]

Grid power costs you $0.10/kWh (Where in California?!)
DIY system with PV and inverter likely to cost $0.025/kWh amortized over 20 years. Higher if solar generation limited.
A commercially assembled battery will cost $0.05/kWh over 6000 cycles, 16 year.

(Both of those ignore time value of money. Utility rate ignores price increases. A wash?)

I don't see the project as worthwhile. Unless you want backup during extended power outages.

If backfeed and 1:1 net metering is available (don't think so, anymore in California), then GT PV with no battery could pencil out. That would basically mean earning value for your labor; turn-key installation of a system works out out $0.10/kWh amortized over 20 years.

 

[eggsnbak0n]

Backup is the main reasoning. Since it will be a back up system to add 4kw of panels is only an extra $1200. The build is in Tennessee. California I have Modesto Irrigation District which is .13 kw/h winter / .18 kkw/h summer rates + connection fees.

I was thinking the panels could charge the backup batteries, then i went deeper down the rabbit hole wondering if i just push that power generation into the home instead of just charging the backup batteries.


Thanks.

 

[Hedges]

Yes, makes sense to over-panel and use CT for zero export, if you use power during the day and don't have net-metering agreement.
You should get permission to connect, because there will be spurious backfeed during load dump.

$0.30/W is reasonable for DIY panels & mounts.
If all power could be used, works out to $0.008/kWh amortized over 20 years. So could make sense to massively over-panel, supplying more of your load rather than buying from grid which costs 20x as much.

 

[eggsnbak0n]

Is the 6000XP EG4 indoor a good solution still for this still or would there be a better inverter for this setup?

 

[Hedges]

I'm not sure regarding functionality and features.
Other people here have experience with other brands; I'm only using SMA.
SMA's new Sunny Boy Smart Energy should support it, but for various reason (including both performance and price) other brands may be better.

First thing to consider is what you're allowed to use, according to NEC, UL, local AHJ, and utility company.
Possibly UL listed ESS is required to get approvals. I understand EG4 18kpv + PowerPro has UL listing.

SolArk has many happy users. Not sure where they stand regarding UL listed ESS.

Inquire of Current Connected (Dexter, HighTechLab). They carry both those brands and some others, should be helpful with these questions, and is a very reputable vendor.

@HighTechLab

 

[eggsnbak0n]

My current major current parts list:

EG4-WallMount Indoor Battery 280AH | 51.2V | 14.3kWh

EG4 6000XP Off-Grid Inverter Bundle 8000W PV Input | 6000W Output | All-In-One Solar Inverter


REC 370W Mono Split Cell Solar Panel (Silver) | REC370TP2SM72

 

[ricardocello]

You should get permission to connect, because there will be spurious backfeed during load dump

There is no such thing as absolute Zero backfeed to grid with CTs, it is physically impossible.
Keep that in mind, should your meter detect backfeed. Your POCO is watching, always watching.

 

[eggsnbak0n]

There is no such thing as absolute Zero backfeed to grid with CTs, it is physically impossible.
Keep that in mind, should your meter detect backfeed. Your POCO is watching, always watching.

I'm not looking to prevent minor leakage. I just don't want the solar / batteries to charge the grid and be used locally only. I will also get the proper permits so I don't care if they watch or not. I've done solar before, but this is my first venture into battery backup storage. The other option is to run a propane based whole house generator which the battery bank will be cheaper than.

 

[Trappy]

Is the 6000XP EG4 indoor a good solution still for this still or would there be a better inverter for this setup?

Deleting stupid comment as you want off grid

 

[Quattrohead]

The EG4 setup would be a good match to your requirements, possibly 2x inverters to reasonably provide power to the 200A panel.
Why are you looking at 2x 200A panels, what are your expected loads ?

 

[eggsnbak0n]

3000 sq foot house with a dock, lap pool, greenhouse, possibly aquaponics. Theatre room. Lots of gaming PC's and other electronics. Also have a PHEV and eventually will get a full EV in the future I'm assuming.