question

charlie-pank avatar image

VE.Bus BMS with non VE.Bus Phoenix Multiplus

I have a VE.Bus BMS and a very old Phoenix Multiplus inverter charger that doesn't have VE.Bus.


My concern is:

- how can the VE.Bus turn off the charger to protect the batteries against overvoltage when charging?

- Can I put a battery-protect in-between the phoenix and the batteries?

- Will the charger be damaged if the BMS disconnects the batteries via the battery-protect mid-charge?

- Are there any other options?

chargerBMSPhoenix Invertermultiplus ve.bus
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5 Answers
bathnm avatar image
bathnm answered ·

Unfortunately you cant use the battery protect, as it is not a device that allows a bi-directional current flow (aka load and charge). It must be installed so that current only flows from the input port to the output port. This is clearly documented in the user guide for the product.

I do not know enough about the non VE.Bus MultiPlus, does it have any remote on/off switches that you can control via the BMS load disconnect or charge disconnect signals? You might need a relay to control that remote switch.

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charlie-pank avatar image
charlie-pank answered ·

Ah, I'd forgotten battery protects are directional - what about 2 in parallel, one for charge one for load?


I don't think I can add 'assistants' to the multiplus so it's not possible to 'tell' it to stop.

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bathnm avatar image
bathnm answered ·

On the current MultiPlus, there is a switch input on the left hand side of the main mother board, which can be used for a remote switch. You shirt the left and middle for "on" and right and middle for "charge". If you do have this remote switch then you can use a relay to control the short.

If no such connector exists on your model, then maybe its time for an upgrade!

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charlie-pank avatar image
charlie-pank answered ·

Does anyone know what happens if the battery is suddenly disconnected from the charger?

1 comment
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Are you thinking charge disconnect? If so none, teh charge disconnect signal is doing what it needs to do stop over voltage. The question might be better what happens to the charger!


the charger should be OK as load is removed it will hit its voltage and just sit there. An Alternator might be a different story as they re-act slower and you can get massive voltage spikes which can damage the rectifier diodes inside the alterntor.

charlie-pank avatar image
charlie-pank answered ·

The alternator has an external regulator. The manual for the regulator says that I can safely switch off the power to the regulator to stop it charging and avoid spikes.


My multiplus does indeed have the external on-off contacts, so I'm wiring into them.

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