Problem: Multiplus 12/3000 shuts down when charging LiFePO₄ battery below +3°C

Q&A and troubleshooting
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1

Problem: Multiplus 12/3000 shuts down when charging LiFePO₄ battery below +3°C

I’m having an issue when trying to charge my LiFePO₄ battery with a Multiplus 12/3000.
Everything is connected normally through a Venus GX.
When the battery temperature is below +3°C, the Multiplus shuts itself off.

The battery has internal heating, and it is supposed to start heating once charging is initiated below +3°C.

If I disconnect the battery completely, the heating system works as it should:
– the heater turns on
– the battery warms up
– and charging then starts normally.

But when the system is fully connected to the Venus GX, the Multiplus simply shuts down as soon as it tries to charge the cold battery.

I’ve tried adjusting all the relevant settings, but nothing seems to change the behavior.

All tips are welcome.

2

Is the “discharge” possibly disconnected from the BMS because it needs the power for the battery… because the Multi relies on the battery… Do you have a BMS that you can check via Bluetooth… to see if the discharging FET is set to OFF?

3

I have not tried to monitor the battery app when it happens. will try it. But it is so strange that it works when I disconnect the BMS battery from the system

4

Can the multi discharge normaly from the battery below 3°C?

5

Yes. -8 inn bms this weekend. No problem

6

Do you know the manufacturer and type of the battery?
It would be interesting to know the voltage at the battery terminals when the multi is still connected and you try to charge it…

Check the shutdown voltages of the Multi… the low voltage shutdown, etc. …
Do you have a way to program the Multi… is the Venus registered in the VRM, or do you have an MK3 adapter?

7

Anda-Olsen 300 AH. https://www.anda.no/anda-lithium-batteri-12v-300ah-bluetooth-heat-canbus

The VRM does not see any drop in volts when it starts. Reset after a few seconds and I can start up again

Lowest possible shut down voltage on the mulit.

full VRM, but no MK3.

8

Why don’t you change the logic? Pre-heat the battery when you need to charge it?

9

Working on it. :slight_smile: this is the intrenal heat. Working with exterior heat that is controlled via node red

10

The battery even has Can-Bus… Do you have any additional data sheets or references here?

Victron does not yet offer any logic for preheating batteries… However, the Multi should still simply provide voltage WITHOUT switching off.
That’s why the voltage at the Multi’s terminals would be very interesting IF the Multi switches off.
So the reason why the Multi switches off can’t be overload… Do the LEDs stay on or is it completely dead…

11

did not see any led. just black…

I now found an email that came from VRM, during one of the chargings at the weekend: ‘Low battery’ on ‘VE.Bus System [261]’

Noting else on the battery.

But why only when I connect the BMS to the venus GX?

12

Unfortunately, I couldn’t find anything on the website either. Integration via Can-Bus would of course be a great addition…
The logic of the battery management system would be most important here… SHOULD the battery stop discharging… the Multi will of course switch off… IF the battery voltage drops too low… the Multi will switch off…
Therefore… measuring the voltage at the terminals when it happens again.

13

I will ask Anda Olsen.

I found a small dropp to 12.59V at the moment the at shut down. But it could be a short blip..

Thank you for your support