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pmolettiere avatar image

Trouble switching battery protect from ve.bus bms charge disconnect

I'm trying to use a Battery Protect to switch the ignition input on an external voltage regulator, to disable alternator charging. According to the Victron manuals, if I connect the ve.bus BMS load disconnect to the battery protect remote H/+ terminal, then the Battery Protect should disconnect when the charge disconnect line floats.

I've programmed the Battery Protect to mode 0-C — the lithium mode.

I'm trying to test to make sure this is working, but when I disconnect the BMS charge disconnect from the Battery Protect H/+ terminal, the relay continues to remain closed, and I have full voltage on both the input and output for the battery protect.

Can someone provide some suggestions?


battery chargingBMSBattery ProtectLithium battery Smart
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1 Answer
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Did you installed the Battery Protect in the right orientation? In your case the alternator have to be connected to the input and the battery to the output.

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I'm not using the Battery Protect to switch the charging current. I'm using it to switch the field to the alternator. My understanding is that disconnecting the charging current from the alternator while it's sending full current would destroy the alternator diodes.

The diagram below shows what I'm trying to do more clearly.

For testing purposes, the regulator ignition is wired to battery positive. The alternator is pulling about three amps, regardless of whether the load disconnect from the ve.bus BMS is present or not. I would expect the Battery Protect to disconnect when the remote+ is free floating.

The Battery Protect is in mode 0-C.

I'm considering just replacing the Battery Protect with a simple automotive relay, but figured I'd ask here first.

Thanks

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