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allan-fraser avatar image
allan-fraser asked

Multiplus Compact compatibility with VE.bus BMS V2 and Cerbo GX

I am going to replace my boat’s ageing AGM batteries with Victron smart lithiums and add a Cerbo GX and display while I am at it. Pre-existing Victron kit includes a Multiplus Compact 12 | 1600 | 70-16 230V (firmware v481) and three Smartsolar 100/30s (firmware v1.61).

I’ve looked at all of the BMS options and the VE.bus BMS V2 is my preference but I have a few questions.

  1. The Multiplus Compact is no longer in production and I’d like confirmation that its inverting and charging functions can be controlled by the VE.bus BMS V2 in response to under voltage, over voltage and over temperature conditions at the batteries.
  2. I’d like confirmation that the GX Display will display the status of the Multiplus Compact (AC load, shore power load, inverting vs pass thru, charge state, etc) despite there being no direct connection between the Cerbo GX and the Multiplus Compact; (the connection indirect via the BMS).
  3. I have a DMC controlling the Multiplus Compact. From what I’ve read in the Cerbo GX manual, the DMC should still work but I won’t have control of On/Off/Charger Only switch via the Cerbo. Is my understanding correct.

In case any of this is relevant, these are other aspects of the system’s design. BMS activated Smart BatteryProtect to disable the DC loads in response to a load disconnect condition. BMS activated Wakespeed WS500 regulator to control the alternator in the event of a charge disconnect condition. BMV-712 Smart to monitor battery state.

I look forward to hearing back from the community.

Thank you.

multiplus ve.bus
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1 Answer
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hjohnson answered ·

As far as the DMC goes, you have your understanding backwards. The Cerbo will monitor the status of the MultiPlus, but cannot control it when the DMC is connected.

In your situation, I would strongly recommend looking at the Lynx BMS rather than the VE.Bus BMS. The Lynx includes the main fuse, a contactor, and most importantly, it communicates via CANBus rather than VE.Bus. As far as I understand it, the VE.Bus BMSs can't be integrated with a Wakespeed (at least not intelligently) whereas the Wakespeed can be configured to take direction fron the Lynx directly over CAN.

The integration gives you the alternator protection, as the wakespeed will go into idle mode if it receives a warning (or alarm) message from the Lynx. It also opens up the opportunity to use the "zero charge" mode on the wakespeed, where the alternator can just support your house loads while maintaining a zero current into the battery.

I do not think that the Cerbo can translate from the VE.Bus to CAN for the wakespeed.

My own system consists of a DIY battery running a REC ABMS, Wakespeed WS500, Cerbo GX, MultiPlus compact 2kva/120v, and various other toys.

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allan-fraser avatar image allan-fraser commented ·

Thanks for your prompt reply.

I can’t recall my reasons for preferring the VE.bus BMS over the Lynx but I’ve now dug a bit deeper into the documentation and the Lynx does look the more complete, feature rich and future-proof option. The “zero charge”mode opportunity sounds like jam tomorrow - do you have any idea when it will be released?

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