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Does the Relay Assistant in a MultiPlus Compact (aka Phoenix 12/2000) continue to work after low SOC shutdown?

Hi there,

I would like to be able to turn a MultiPlus Compact (Phoenix 12/2000) off when reaching a defined SoC. This part is easy. I would however also like to continue to use the programmable relay in the same MultiPlus to turn off DC loads via a Battery Protect when the SOC reaches a (lower) threshold. In other words, what I have in mind is turning off AC loads at say 25% SoC and turn DC loads off (relay driving a Battery Protect) at 15% SoC.

Is that possible?


MultiPlus Quattro Inverter ChargerPhoenix InverterSOC
2 |3000

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Hello Jan,

that's a really good question. A BatteryProtect is always installed in the circuit diagrams. Don't you just like to try it out?

I am very curious to see if someone is already using it in this way.


Hi @Ulrich,

While I don't mind experiments, this is for one of my clients. Before recommending which bits to buy, I'd like to know that this solution actually would work.

The Battery Protect acts on voltage, not ideal for LFP. Much better if the DC loads can be disconnected based on SoC, just like you can do with the inverter. In this case, they don't have a BMV (which also has a relay) but an existing charger controller with shunt which acts as a battery monitor so I can update the SoC of the Multi Compact via VenusOS.


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