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> and with batteries you end up fully self sufficient when the grid goes down. My understanding is that the majority of installs are not capable (allowed?) to
by andreareina 4y ago
> and with batteries you end up fully self sufficient when the grid goes down.
My understanding is that the majority of installs are not capable (allowed?) to run when the grid is down. I do know that at the very least you'd need a transfer switch to ensure you're not backfeeding the grid when it's not expecting it, like with a generator.
Now that I think about it, I wonder if a generator could provide the reference signal for the inverters to synchronize against. You'd still be burning fuel at whatever the generator's idle consumption is, but that'll be less than actually using it for power.
- stainforth 4y agoCould you have a parallel system that the house power switches to? Or even separate outlets to plug appliances into
- andreareina 4y agoSeparate outlets means running cable that you won't use most of the time, and having to remember which outlets go to which circuit. A transfer switch allows you to isolate and switch between two power supplies so that your house circuits are only ever connected to one of them, and the two supplies are never in the same circuit[1]. They can be had for a few hundred depending on the load[2]. [1] this is a break-before-make switch. There exist make-before-break switches for when you need uninterrupted power supply, but they're not appropriate for this case as you'd be backfeeding into the grid which is dangerous and illegal. [2] https://www.lowes.com/pl/Generator-transfer-switch-kits-Generators-Electrical/4294641570 https://www.lowes.com/pl/Generator-transfer-switch-kits-Gene...
- margalabargala 4y agoAnyone can fortunately only make the backfeed mistake once, as whatever generator they backfeed will no longer exist after the connection is made.
- margalabargala 4y agoThere's no need for that. Turning off your main breaker in your panel will disconnect you from the grid and prevent backfeeding.
- bsder 4y ago> My understanding is that the majority of installs are not capable (allowed?) to run when the grid is down. Capable, IIRC. I seem to remember that you need to have a type of inverter that is quite a bit more expensive (several kilodollars) if you want to be able to run disconnected from the grid. Most people opt for the cheaper inverter as there's not a lot of difference if you don't also have a battery storage system.
- cfn 4y agoMost offgrid inverters have a generator input to which they will switch when you start the generator. If you replace the generator with the grid (and you have batteries) and the grid goes down they switch seamlessly to the batteries - well, within a fraction of a second, some applainces "blink". I am actually using this system as a sort of UPS for our office
- djcapelis 4y agoNah. It’s a standard feature of most battery systems to run when the grid is down. Solar without battery doesn’t, (and the solar itself cuts out) but if you have battery systems involved for storage, you’re already capable of them interoperating with the grid, or without it. As for getting reference from a generator, no need. You can get all that from the batteries and they’re increasingly planned to be used for grid scale black start.
- KaiserPro 4y agoThe Tesla power wall has an optional huge contactor that isolates the mains power in the event of an outage. (which of course is an optional extra) However the power swapover isn't seamless, so most computers will reboot. That means that grid tied inverters can continue to function, but its not a UPS/ I suspect there are better/faster battery backup systems out there, but the the powerwall2 aint that.
- andreareina 4y agoI don't know there's any legal battery backup that's not "break before make". If there is I'd love to know what the operating principles are.