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jordanb asked

Can BMV-7xx relay control multiple charge sources

On my boat I have a MultiPlus 120/3000 which I use when connected to shore power, or with a diesel generator. I also have a propulsion engine with a large frame alternator and a Balmar voltage regulator.

I understand that I can wire the relay from the BMV-700 to the Balmar voltage regulator, and using a Victron SolidSwitch 104, I can program the BLM-7xx relay to enable/disable the Balmar based on SOC%.

I also understand that I can wire the relay from the BMV-7xx to the MultiPlus - via the AUX1 or AUX2 inputs - I can similarly get the BMV-700 relay to enable/disable the charger/inverter based on SOC%.

Is there any reason I can't wire the BMV-7xx relay to both? As in wire the BMV-7xx relay to a terminal block and then from there run a wire each to the SolidSwitch104 to control the Balmar, and another wire from the terminal block to the MultiPlus.

As far as I understand how electricity works, this should not be a problem. I was also thinking I could run a 3rd wire to a latching relay connected to the solar panel charge controller (a MPPT 75/15).

Will this work? Thanks!


Multiplus-IIBMV Battery MonitorRelay
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2 Answers
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jordanb answered ·

After a day my question has scrolled down to like page 8 - this forum has a lot of traffic obviously.

Can anyone help answer my question please?

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jordanb answered ·

I guess this was a stupid question. Obviously you can. It works. Thanks anyway.

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jordanb avatar image jordanb commented ·

Well, I was wrong it does not work - I can't figure out how to set up the relay so it can be connected to both a MultiPlus 2 relay and a SolidSwitch104 (connected to a voltage regulator). It seems like the MP2 requires a closed loop with the AUX relay and the BMV where the MP2 sends 5.2v through the wire and the BMV relay closes to make the circuit.


So how do I work the SolidSwitch into that and use the same relay for both? I thought I had it set up right, but I realized it wasn't working and re-wired it to the MultiPlus as described here (https://www.victronenergy.com/live/dc_coupling:using_bmv_soc_in_a_vebus_assistant_setup) - but now what, I have no way to turn the SolidSwitch on and off.

Maybe I can use the Gen Start/Stop relay in the CerboGX to do that?

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