btank avatar image
btank asked

Can I connect more than one BMS to the Venus GX?

I'm trying to connect 2 batteries from 2 different suppliers

  1. A pylontech battery with a builtin BMS that connects directly to the Venus GX
  2. An additional battery with a separate BMS that can also connect to the Venus GX

Can I connect these 2 batteries (through their individual BMSes) at the same time to the Venus GX?

How does the Venus GX manage 2 BMS inputs?

BMSVenus GX - VGXPylontechVEConfigure 3
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1 Answer
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi, sorry, but it doesnt manage it: the code is written to expect one battery - not multiple.

it wouldnt know which inverters or mppts to control based on which of the two bms-eses parameters.

our philosophy here is been that this is too much of an edge case to make code for; and one options is to take two GX devices.

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ commented ·

Hm I should nuance that a bit probably: it can monitor multiple batteries; ie log it to vrm and show on screen.

But it can use only one for controlling the inverters, chargers, and so forth.

from all available BMS-es, it will use the one with the lowest device instance

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ mvader (Victron Energy) ♦♦ commented ·

Ps2: I’ve updated my above comment a bit; and thought of something else: you can’t have both those BMS-es on a single can us port. The BMS-Can protocol doesnt use addressing: the Cerbo won’t be able to distinguish one from the other.

so to do this, wire each to a a different port. Configure the VE.Can port to the right profile as well (I suppose BMS-Can 500 kbps).

And then see what happens. Do both show up individually in vrm and do they have a different device instance number there?

and in the device list on the UI?

It might work, or might not work. It needs testing to find out.

If it works, its “by accident”: we dont design for this.

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ mvader (Victron Energy) ♦♦ commented ·

Ps3: Another update: it wont work, not even when connected to different canbus ports on the cerbo. Sorry.

You could use a BMV to monitor the second bank.

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btank avatar image btank commented ·

@mvader (Victron Energy) A few follow ups:

  1. Do I need to connect and sync the 2 GX devices (e.g. using CAN port, GX to GX)?
    1. Is the functionality already available on VE software or would I need to write my own code to do this?
  2. Also, I am trying to combine 3x10kVA inverters for a 3 phase output. If the 2 GX devices are synced will that also sync the Inverter output?
    1. How should I connect the inverters to make sure I can still get a synced 3 phase output (even though the batteries may be different and with different voltage/current)?
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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ btank commented ·

Hi Btank, sorry, myself and from Victron side we can't help any further than what I said above.

Also I didn't understand earlier that you wanted to sync multiple GX devices: you can do that a little bit with all sorts of limitations and only in v2.60 and later; but then only for readout on a "slave" unit. Not for making one comprehensive system.

Having three 10kVA Inverters in 3 phase needs by design and definition one battery bank, see here: there is no way around that.

I hope someone else can help you; if not then sorry - too far away from normal & supported use cases.

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ea7777777 avatar image ea7777777 mvader (Victron Energy) ♦♦ commented ·
Hi, I can´t understand, why you still don´t support this in 2024?! There are more and more people who want to run more than one 16s Battery! And by the way... the logic for more batteries is for sure not so complicated!
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