yes.  i have a self-built powerwall with a pip4048 inverter (has an automatic transfer switch in it), but i also have a 3000w renogy ups inverter (again has automatic transfer switch) coupled with a 200ah lifepo4 inverter. then a small few hundered watt cyberpower ups running nut / upsd.  works like this.  powercut = powerwall kicks in, 13kw worth of batteries runs. that runs out, renogy inverter kicks in, that runs out, cyberpower ups kicks in. that runs out? shuts shit down until grid power restored.
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