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Fideri avatar image
Fideri asked

Share power in battery: ideas?

Hi All,

Say I want to allocate two users 10kWh each of power stored in batteries or the output of an inverter, what is the best way to do it?

It shouldn't matter but in case you are curious, I have a single off-grid solar system installed in an 10-apartment block. I don't want John to turn on the water heater, use up all the power, and leave Jane in darkness. I have two Yangtze PV arrays, two Victron MPPTs, eight PylonTech battery modules and one Victron Quattro inverter.

I don't mind purchasing extra equipment and getting my hands dirty (haha, adult boys' toys). So far, I have looked at sub panels and sub metres but nothing seems to have the feature I desire.

I can monitor the apartments' consumption and I can control through fuses how much power an apartment draws at a given time. But I can't figure out how to divvy up the power so that John can switch on his water heater if he wants and go to hell once his share is used up and Jane will still have lights.

Fideri

power meter
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1 Answer
wkirby avatar image
wkirby answered ·

Moving to Modifications section where others may be able to provide a better answer too.

One way I can think of is to connect RS485 energy meters to the Cerbo or whatever GX device you have. The John, Jane and the others can have their electricity feeds via their own meter.
Then some sort of node red flow to read the meter at a certain time each day to be the baseline for the start of a new day. This number is subtracted from the real number as it counts up and when the difference reads 10kWh a relay opens or closes to activate or deactivate a contactor which in turn cuts off John's supply if he takes advantage.

This system need not be integrated with the Victron system at all and could be completely stand alone since the source of the electricity is irrelevant, you just need to count energy with a meter and cut off if a limit is reached.

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