Question. Powerwall and power outages

Question. Powerwall and power outages

If I have an PV system with integrated Powerwalls and the utility power shut off for any reason.
Is there short period of time I would be without power?
Or is it like a true U.P.S. and the power switch over is instantaneous.

ACDC 2GO | 07. März 2019

It is instantaneous, you will not have to run around and reset your clocks after a power outage unless the power is out for longer then your battery reserves.

mrburke | 07. März 2019

@ACDC - Thanks

woferry | 07. März 2019

My understanding is that it depends on the state of the Powerwall when the outage occurs. If the Powerwall was currently discharging, I would expect it to be seamless since it's already providing power. If the Powerwall is idle (not charging or discharging) or charging, it first has to detect that the grid has gone away, and then turn itself on for discharging. This is never instantaneous, it takes time. Most things in the house can probably ride through this unnoticed (you may not see your lights flicker, for example), but sensitive electronics might still brown-out so your computers and DVRs and the like might reset. So some simple UPS's (they don't need to power the load for more than a fraction of a second) may still be necessary for some things. The trick is that the Powerwall plays with the line frequency to turn off any connected Solar Inverters when it doesn't want the extra power (like when it's near fully charged), and some UPSs will see this as a bad line input and keep running from their own battery rather than switching back to the Powerwalls. Others are more tolerant to input frequency and will switch back to AC just fine.

At least that's my understanding, I have a Powerwall but am waiting for PTO of the solar system it's connected to, so I can't test any of this myself yet.