Tesla Motors Club

Hey All,

I recently got 2x powerwalls installed for the purpose of a whole home backup that was capable of running my AC.

I installed a SureStart in the AC unit as well to reduce inrush current demands.

I've been running a few tests but no matter what I do I can't get the powerwalls to fire the AC unit.

I get a huge voltage drop in the house when the AC kicks in and the powerwalls are in backup mode.

Various devices not on a UPS will restart (like my google homes).

In my testing I've gone so far as to turn off all the breakers, except the AC condenser, and then manually trigger the contactor. Voltage sags and the SureStart errors out for low voltage.

With line power on the house I've measured a 6kW (~25A) draw spike when the AC fires up. This is well within the 10kW/14kW max for two powerwalls.

I checked the wiring on the powerwalls and each one has a 30A breaker with #10 wire, which seems fine?

The AC has an 8-2 NMB wire that goes over to it, which should be enough, as the name place calls for a minimum ampacity of 32A.

So for me at least, all signs are pointing at the powerwalls.

Have any of you folks successfully fired up your AC units running in backup mode?