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by Animats
2 hours ago
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There are several variations on this idea, and the web sites are confusing. First, there are ones that are just a big UPS. You plug them into the wall, and plug loads into them. They may try to level your power usage. No problem with that. Good for refrigerators. That seems to be what "Pila" is selling. This class of device seems to come with deceptive ads which do not show cords from loads plugged into the box. Then there are ones that purport to pump power back into their wall outlet.
That has safety issues, starting with its male power plug being an output.
It can't provide power when there's no input power, because it would try to drive the the whole grid during an outage. It's mostly for taking advantage of variable power pricing. This seems to be what "Regen" is selling. These are apparently available in Germany, but must be installed on their own dedicated circuit, so you don't have a load and a source on the same side of the breaker. Otherwise, you could potentially have an overload without a breaker trip. Regen is trying to get them into the UK, but old UK ring main wiring is a bad match to this. Gotta have a breaker between load and source. The trouble with these things is that, plugged into the wrong outlet, they create a gap in overload protection that won't show up until something goes wrong. |
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The downside is that we have three phase power supply anywhere halfway recent. And that only gives you a single phase. In _most_ cases that’s fine, because you get a net-sum of all three phases at the meter, but technically you are only drawing/supplementing one out of three phases. In practice this likely doesn’t matter since different house put theirs on different phases and it all washes out.
[1] the DC side can have up to 2kW of panels. But that’s not visible to the grid