Suggestions for whole house off-grid system?

[hsync33]

Here's another option:
This is a hybrid inverter than can work as a backup using battery power alone (without the grid). It can run from 48V all the way to 400V plus. The batteries are rated 2.5KW and can be attached in series to increase capacity, with increasing voltage / capacity, so they must have a suitably protected BMS to accomodate 400+ Volt disconects.

The price is quite modest as far as a comercial solution goes. While this one is based on poland, they have a UK distributor too here but they don't specify if the lower power variants can run without the grid.

 

[Hedges]

A hybrid, it says. Data sheet is also in Polish and my browser didn't translate, but I see it says battery 180 to 600V.

It has to be told what voltage for bulk and float. Is that settable by the user? The HV inverters I've seen talk to specific batteries (and need different firmware for different models, or at least no longer work with some model batteries if latest firmware installed.

I think they talk to the battery, tell it to turn on its output, are told what voltage for charging, etc. So the question is how to make them work with a dumb battery.

Some people have feed EV HV battery into PV input of an inverter, so discharging only. One guy here did that, and it worked, but couldn't do much surge. 48V worth of automotive starting batteries on battery input made it better.

Mostly a software problem, and that is what's most difficult if not documented for the user.

 

[hsync33]

A hybrid, it says. Data sheet is also in Polish and my browser didn't translate, but I see it says battery 180 to 600V.

It has to be told what voltage for bulk and float. Is that settable by the user? The HV inverters I've seen talk to specific batteries (and need different firmware for different models, or at least no longer work with some model batteries if latest firmware installed.

I think they talk to the battery, tell it to turn on its output, are told what voltage for charging, etc. So the question is how to make them work with a dumb battery.

Some people have feed EV HV battery into PV input of an inverter, so discharging only. One guy here did that, and it worked, but couldn't do much surge. 48V worth of automotive starting batteries on battery input made it better.

Mostly a software problem, and that is what's most difficult if not documented for the user.

That inverter runs it's own branded battery storage and communicates with the BMS, adjusting the voltage to whatever batteries are installed. The higher the number of batteries, the higher the voltage and the storage capacity (they are wired in series).

It's a comercial ready made solution. I don't know whenever it would run with other battery brands (Some chinese BMS seem to have figured our protocols for some of the more common inverter brands) but that still classes as a ready made solution, likelly not user customisable.

I immagine at the lower voltages, there might be a limit in how much power it can deliver, similar to PV trackers, where they need a minimun voltage to deliver full load (but are happy to work at partial load at lower voltages).

I guess for a fuly customisable setup you should probably go the route of my previous post.