Off Grid Non-Critical Load Sub Panel

[emptyspaces]

I plan to be fully off grid. I want to make sure that critical loads get priority. In an off grid situation where your PV/Battery/generator system is your source, is it standard practice to put the non critical loads on their own sub panel that could then be turned off easily; leaving your critical loads on the main panel? Or would you put the critical loads on a sub panel and bypass? Let me know why and how you would best achieve it.

How would you recommend auto turning off non-critical loads when the battery bank reaches a certain %?

 

[Hedges]

I use Sunny Island. Each inverter has two signaling relays.
One is set by default to switch when SoC drops to 30%, switch back at 50%.
Another can be set at a different level.

My GT PV inverters (AC coupled) are on the critical loads panel so never disconnected.
A "load shed" relay disconnects another main loads panel at 30% SoC, letting battery inverter keep GT PV inverters and critical loads running while waiting for the sun to come up.

I haven't configured second load-shed yet. It could go to HVAC thermostat, could disable dryer, etc.

Because my system does frequency shift power control, ideally loads would be continuously variable based on frequency. But I don't find off-the-shelf solutions for that.

Some inverters provide SoC relays, some SCC do, and I suppose separate battery monitors.

 

[Ampster]

How would you recommend auto turning off non-critical loads when the battery bank reaches a certain %?

If you have enough money you could buy a Span load panel and do it dynamically. The least expensive way is to do it manually. Somewhere in between are programmable breakers that can be triggered by senors that operate when battery voltage hits a setting. That is what @Hedges was referring to.

Design really depends on whether you have a grid or are truly off grid. If you are off grid a single load panel would be the most cost effective and the user would just turn on loads appropriately as needed. A true off grid scenario would not need a separate critical loads panel because any circuit could be critical when you need it