Grid Tie Solar, Home-brew UPS, and RV

[soylentgreen]

Brainstorming please: I'm looking for advice on how to improve my current setup.

Home: 5KW Solar with Grid Tie inverter.
Computers: I have a rack of servers, which has a home-brew UPS with about 4KWH of battery power.
RV: I have a small van with a 1KWH LFP battery and 800W 120VAC inverter

I live in California, and even when "The Grid" is OK, we seem to have frequent power outages on top of that.

When a power outage happens:
* My server rack is fine, since it's on UPS and has about 36 hours of runtime.
* My grid-tie solar system goes offline
* And everything else in the house goes dark

If the power outage is longer than a few hours:
* I start running extension cords to the inverter in the RV - I have to pull the fridge out from the wall, plug it into the inverter, run a long extension cord upstairs to power my desktop computer, etc.

This could be better, no?

Ideas:
* get a whole-house battery backup such as Tesla Powerwall. However, I believe powerwalls are not UPSs - they don't switch on immediately, so I'd still need UPSs as well. Is this true?
* replace my grid-tie solar inverter with one which works during an outage, such as the Sunny Boy 5 SPS. However, I belive these are also not UPSs - requires a manual switchover. And if the outage is at night, of course it won't work.
* replace my home-brew UPS with something more substantial: perhaps an EG4 48V battery and a Victron Inverter/charger? I could then plug in all my critrical loads (Server rack, refrigerator, etc.) to the Victron, so they would auto-switch.

Ideas?

 

[BentleyJ]

Whole house back up systems are generally not exactly the same as a UPS in that they normally operate in Pass-Thru mode, inverter not operating, while the grid is available. If there is a power outage the back up system starts inverting and picks up the load. This can take 5 to 20mSeconds so some sensitive items may still need a small UPS. For example an office type tower computer with no internal battery. For most other items like lights, refrigerators or appliances with clocks Etc. The transition is so fast they are not affected. I believe some back up inverters can be configured as a UPS system that is engaged all the time but this is only for a selected few models.

You may not need to replace your existing grid tie system as its possible to AC Couple a new battery inverter with the existing system depending on a few factors which I will skip for now in the interest of brevity.

The new system would power your critical loads panel and everything connected to it, however, a smaller UPS may still be necessary for something like a Server Rack that would be sensitive to power fluctuations during the short auto switch period.