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 | 7 mars 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 | 7 mars 2019

@ACDC - Thanks

woferry | 7 mars 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.

mastruck | 25 mai 2019

I have a Powerwall system and we just had a power outage. The switch over was quick, but not instant. I had to reset the clock on my stove and my server was shut off.

sleeper service | 26 mai 2019

I have a 22 panel SolarCity system with 2 Tesla Powerwalls. I have Pepco as my utility and i've had 18 events since May 2018. The switch to the Powerwalls was not noticeable for 16 of them. With one event a server went off but a clock driven by the line frequency was OK. The other was the reverse: the server was OK but the clock went off.

xoxoteslamom | 29 mai 2019

Last night notification flashed on my cell phone that Storm Watch had been activated for our Connecticut area and our Powerwall was being charged by the grid. I checked the Tesla App and indeed there was the grid charging the Powerwall. And there in Bright Yellow/Orange was Storm Watch label under the Powerwall Green Circle!!!
Before the thunderstorm arrived the Powewall was charged up 99%.
Fortunately just rain poured down, and we had none of the potential hail, and we did not loose power.
Now I know how Storm Watch works!

dortor | 31 mai 2019

for me switch overs are instantaneous or close enough not to matter - had a 3 hour outage this past weekend in Watsonville, CA - no one at the house noticed the neighborhood was without power - the only reason I noticed was PG&E utility has a service to text you about outages "in your area" - when I received the PG&E text I checked the Powerwall and sure enough we were currently on battery+solar and had been for about a hour…

the switch over depends on what "mode" you are in - if you are in "self powered mode" there is _NO_ delay because the battery is already engaged and providing power to the house - if you are in "backup only" mode there me be a sub-second cut-over as the grid goes "down" the relay's in the Powerwall gateway will take some number of milliseconds to "kick in"…in both cases my experience is the whole switch over is normally no big deal with only minor annoyances from "loss of power"