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by dmazzoni 874 days ago
I was surprised to discover that even with a backup battery, a typical solar install is not designed to power your whole home in the event of a power loss. Only some inverters support it, and most backup batteries can't generate enough amps to start an A/C unit, even though they'd have enough to run it for a while.

Tesla's PowerWall is more capable than some, but I've heard nightmare stories about working with Tesla customer service so I stayed away from that one, even though technologically it's probably the most advanced.
3 comments
pbmonster 874 days ago
> I was surprised to discover that even with a backup battery, a typical solar install is not designed to power your whole home in the event of a power loss.

Might even be illegal, depending on jurisdiction. For good reasons, you could kill electricians working on the local grid or firefighters working on your house if you're not careful with the install and adding local shut-offs.

My battery turns off when the grid goes down, but it has 3 outlets directly on the body of the battery, and those always work. I run extension cords from those when the power goes.

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Faaak 874 days ago
Bullshit. All "hybrid" inverters nowadays (grid tied + battery backup), auto island themselves when the grid is out.

That misconception is now 15 years old

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pbmonster 874 days ago
That system is 5 years old. It feeds electricity back to the grid.

For an "auto island" functionality, I would need relays controlled by the inverter on all 3 phases between the electricity mains and my main switch box, right? I don't have relays like that.

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zo1 874 days ago
How much electricity do you use? I have a low range inverter (5KW) and it can give me 4.5kw sustained power from my battery and as much as I want from the grid because it acts as a pass through. At 220V that's 20Amps, or 40A I guess with your American 110V supply.

Add another battery and bigger inverter and you can double that. Unless you've got a kiln or perpetually running hot water heating, I'm left baffled.

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rssoconnor 874 days ago
According to https://www.reddit.com/r/Generator/comments/15uy9dw/ac_start... an AC can require 79A on startup.

Though apparently there is a thing called a "softstart" that can be installed to mitigate this.

I don't actually know anything about this stuff. I just watch youtube videos.

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Faaak 874 days ago
The problem is in the "whole home". I'm pretty happy to have my lights/wifi/induction cooktop/etc. running when the power runs out.
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