I made some diagrams (gotta have diagrams!) to help me wrap my brain around this stuff. So here is the first step as I see it:
The grid is the primary source, and the generator is the secondary. Looks like the transfer switch would be wired up like a sub panel or junction box. With the neutral isolated but not switched. Here's what I think is going on inside a transfer switch:
Top lugs are grid, bottom lugs are generator, and the middle lugs go out to the sub panel. Out is connected to either grid or generator via a "knife" switch, having the effect of being an on-off-on double throw.
The sub panel is your basic split phase sub panel. I've installed these before, no problem. The essential circuits will all be moved here. I don't really need a diagram for this, and you guys probably don't either, but I was having fun drawing, so I'll share it anyway.
So the challenging part for me is adding the inverter and battery. Maybe it depends on which inverter I buy, but I think it would hook up something like this:
Maybe the inverter should go between the transfer switch and the sub panel. I don't know. But at this stage the inverter/battery becomes the secondary source of power, and the generator is tertiary. The grid would still be the primary source for the sub panel. In the event of a power outage, the battery would supply the sub panel until it got low, at which point I'd start up the generator to charge it and run the sub panel. I figure a 6kW battery, 6kW inverter, and 6kW generator should go well together. It's very unlikely the sub panel would be using 6kW for most of the time, so the generator should be plenty to charge up the battery while also running the sub panel. And when the battery is full, I'd shut the generator off. During short outages, the generator may not be needed at all, and the battery could be charged by the grid later when power is restored.
During normal happy grid times, the inverter and battery wouldn't be needed at all, and the inverter could be shut off. I suppose a battery maintainer could be used to ensure the battery is topped off and ready to go. Saving much of that 100W idle consumption of the inverter.
The last stage would be adding solar panels.
Doesn't look like much of a difference on the diagram, but installing a solar array would probably be a thing I'd have to hire out. And it will change the whole dynamic of the power system. The grid would still be the primary source of power for the main panel, but the sub panel's primary would be the solar. The inverter will most likely have at least 1 MPPT solar controller built in, so I don't have to worry about that. I did some measurements a while back, and I don't remember details, but I think if I covered all of my potential areas with panels I could get something like 10kWh per day in the summer and 1kWh per day in the winter. Very disappointing results, which prompted me to go this route instead of trying to power my whole house with solar.
Anyway, the battery would be the secondary source for the sub panel, followed by the grid as the tertiary. And the last one (quaternary?) well whatever #4 would be called would be the generator. Though I'm not sure the inverter would know the difference. I guess hybrid inverters can tell if the grid is on or not, and so they know whether to back-feed excess power into the grid or keep it isolated. I'll have to talk to my utility provider about that. And during inadequate sunlight, the inverter may also be able to use some solar and only draw what's needed from the grid.
I'm guessing the generator, inverter, and battery should all match each other as fare as Watts go. So I'm thinking with a 6kW inverter, I should also have a 6kW battery (minimum) and a 6kW generator. I have my eye on a 6kW inverter generator it's got both electric start, and a pull chord. Runs on either gasoline or propane. Outputs split phase 240V.
Just as an aside, I recently got one of those clamp meters that measures AC Amps inductively. I measured my furnace last night. It's a central forced air electric furnace. The heating element and the blower are on different circuits. And I suspect the labels may be swapped. But what I got was something like 42.5A and 20A. So the furnace in total is 15kW. I looked around, and it seems that is a reasonable amount of power for a furnace sized for my house. This year I hope to get bids on some duct improvements and a heat pump. But that's another story for another thread. I just thought it was kind of interesting.
That's what I'm hoping to do eventually. Run the sub panel off solar/battery. If I ever have excess power, I'll have to figure out what to do with it. The main function though, is to provide backup power to select circuits during a grid outage.I made some diagrams (gotta have diagrams!) to help me wrap my brain around this stuff. So here is the first step as I see it:The grid is the primary source, and the generator is the secondary. Looks like the transfer switch would be wired up like a sub panel or junction box. With the neutral isolated but not switched. Here's what I think is going on inside a transfer switch:Top lugs are grid, bottom lugs are generator, and the middle lugs go out to the sub panel. Out is connected to either grid or generator via a "knife" switch, having the effect of being an on-off-on double throw.The sub panel is your basic split phase sub panel. I've installed these before, no problem. The essential circuits will all be moved here. I don't really need a diagram for this, and you guys probably don't either, but I was having fun drawing, so I'll share it anyway.So the challenging part for me is adding the inverter and battery. Maybe it depends on which inverter I buy, but I think it would hook up something like this:Maybe the inverter should go between the transfer switch and the sub panel. I don't know. But at this stage the inverter/battery becomes the secondary source of power, and the generator is tertiary. The grid would still be the primary source for the sub panel. In the event of a power outage, the battery would supply the sub panel until it got low, at which point I'd start up the generator to charge it and run the sub panel. I figure a 6kW battery, 6kW inverter, and 6kW generator should go well together. It's very unlikely the sub panel would be using 6kW for most of the time, so the generator should be plenty to charge up the battery while also running the sub panel. And when the battery is full, I'd shut the generator off. During short outages, the generator may not be needed at all, and the battery could be charged by the grid later when power is restored.During normal happy grid times, the inverter and battery wouldn't be needed at all, and the inverter could be shut off. I suppose a battery maintainer could be used to ensure the battery is topped off and ready to go. Saving much of that 100W idle consumption of the inverter.The last stage would be adding solar panels.Doesn't look like much of a difference on the diagram, but installing a solar array would probably be a thing I'd have to hire out. And it will change the whole dynamic of the power system. The grid would still be the primary source of power for the main panel, but the sub panel's primary would be the solar. The inverter will most likely have at least 1 MPPT solar controller built in, so I don't have to worry about that. I did some measurements a while back, and I don't remember details, but I think if I covered all of my potential areas with panels I could get something like 10kWh per day in the summer and 1kWh per day in the winter. Very disappointing results, which prompted me to go this route instead of trying to power my whole house with solar.Anyway, the battery would be the secondary source for the sub panel, followed by the grid as the tertiary. And the last one (quaternary?) well whatever #4 would be called would be the generator. Though I'm not sure the inverter would know the difference. I guess hybrid inverters can tell if the grid is on or not, and so they know whether to back-feed excess power into the grid or keep it isolated. I'll have to talk to my utility provider about that. And during inadequate sunlight, the inverter may also be able to use some solar and only draw what's needed from the grid.I'm guessing the generator, inverter, and battery should all match each other as fare as Watts go. So I'm thinking with a 6kW inverter, I should also have a 6kW battery (minimum) and a 6kW generator. I have my eye on a 6kW inverter generator it's got both electric start, and a pull chord. Runs on either gasoline or propane. Outputs split phase 240V.Just as an aside, I recently got one of those clamp meters that measures AC Amps inductively. I measured my furnace last night. It's a central forced air electric furnace. The heating element and the blower are on different circuits. And I suspect the labels may be swapped. But what I got was something like 42.5A and 20A. So the furnace in total is 15kW. I looked around, and it seems that is a reasonable amount of power for a furnace sized for my house. This year I hope to get bids on some duct improvements and a heat pump. But that's another story for another thread. I just thought it was kind of interesting.
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