Powerwall Charge Rate

[Dan123]

I am in southern Florida, placed reservation for 2xPW2 back in 9/17. Just got an email that they are ready to proceed with the installation.

I am debating whether I need one or two. I understand that one is limited to 5KW continuous power, but my house almost never exceeds that, and during the day solar will provide more than 5KW anyway.

What is the maximum charge rate (how much power can one PW accept from the solar system)? What happens when the grid is down, and the available power exceeds what the PW can accept?

If I want to get the 30% tax credit, is there a setting to charge PW only from solar and not from the grid?

 

[miimura]

Each Powerwall can charge at 5kW. Normally, Tesla does not want to install more than 5kW of solar per Powerwall on the backup side of the Gateway. If you really want the system to work properly in backup mode with more than 5kW of solar, you should get the second Powerwall.

You don't need to do anything to be tax credit compliant in the US. The Tesla software enforces charging only from solar when their units are installed in the USA. The Powerwalls will only charge from the grid when Storm Watch is activated by a sufficiently high NWS Alert.

 

[cwied]

One other note: they will not want any breakers greater than 30A per Powerwall on the backup side. If you have any circuits you want to back up that have a breaker greater than 30A, you'll need more than one Powerwall.

 

[Merrill]

Maybe someone can tell me how long I can stay on 2 Powerwalls when power goes out. I have a 6.5kW solar system and only need about 60% of the house backed up. In the summer I usually generate around 38kWh per day.

 

[jeep1979]

Merrill, your PV system is about the same size as mine and I have 2 Powerwalls doing a whole house backup. I run all the time in self-powered mode and only sometimes in December and January do I need to pull off the grid. Right now, I am getting no lower than 30% on my Powerwalls and by 2pm on a sunny days the Powerwalls are completely recharged. Big ticket items are my plug-in hybrid, golf cart, spa and still sending back to the grid at this time. In summary, right now as long as most the day is sunny, I can run indefinitely on solar and my Powerwalls.

 

[Merrill]

Merrill, your PV system is about the same size as mine and I have 2 Powerwalls doing a whole house backup. I run all the time in self-powered mode and only sometimes in December and January do I need to pull off the grid. Right now, I am getting no lower than 30% on my Powerwalls and by 2pm on a sunny days the Powerwalls are completely recharged. Big ticket items are my plug-in hybrid, golf cart, spa and still sending back to the grid at this time. In summary, right now as long as most the day is sunny, I can run indefinitely on solar and my Powerwalls.

Thanks jeep1979, just concerned because our power company says that during the summer if the wind, humidity, temperatures and meet their criteria for shutting power off that it might take them up to 12 days to inspect the power poles and lines before they will turn on the power. Seems a bit over the top but want to be able to power some of our house during that situation.

 

[jeep1979]

I don't think you should have any worries especially if you are looking to only power some of your house. I power my entire house and have enough solar during the day to run my house and recharge the Powerwalls and then run off the Powerwalls in the evening. IN my area we have had a number of planned power outages during the day lasting from 5-8 hours and I have experienced no issues. Again, I am running in self-powered mode, running basically off-grid 24 hours per day.