question

anton859 avatar image

How to disable mppt charge with cerboGX?

Hello, there is a system of three batteries connected to lynx ion bms, two mpp 100/20 and mppt 150/35 and one quattro inverter, all of them are connected to CerboGX. There was a problem when turning off the BMS when the main contactor opened, the solar controllers continue to supply voltage to the system from which part of the circuit is energized, an error is displayed on the monitor about the loss of communication with the BMS. Is it possible to somehow solve this problem, so that charging stops when BMS is turned off, mppt controllers are connected to the ve.direct cerbo cable

MPPT - Solar Charge Controllercerbo gxBMSVE.Direct
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Anton859

When the BMS communication is lost, the MPPT's reduce output voltage to 12/24/48 volt.

2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Jan Zmrhala avatar image
Jan Zmrhala answered ·

HI, please read the manual here, part 6.:


when there is no BMS the MPPT follows it's own rules. That is why you need to setup the MPPT as well.

https://www.victronenergy.com/live/battery_compatibility:byd_b-box

3 comments
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

I found it in the settings only using a non-inverting cable ve direct, which in turn excludes the ability to see data on a cerbo monitor

I use a Battery protect installed in reverse exactly because of this. I want the VE.Direct port to go to my GX, so I take the output of the MPPT and run it through the BP "In" port and the "out" port is connected to the DC bus. It would be nice if Victron would include a remote on/off port on their mid tier MPPTs for use with a non-managed lithium battery.

Thanks for the help.

Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Anton859

are you using DVCC?

3 comments
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

The problem was not solved by turning on DVCC mode in the settings, when BMS is turned on in the MPPT settings, the status is slave and the control goes from the BMS, but as soon as I turn off the BMS, the MPPT charging controllers continue to work and transfer voltage to the network. Can you please tell me if such an algorithm of operation is possible that when the BMS is turned off, the charging controllers stop giving off voltage?

Hi @Anton859

Why do you loose connection to the BMS?


A work around (but not really the answer) could be:

set the charging voltage of the system very low, that way when no bms is present, it will not charge.

anton859 avatar image anton859 Daniël Boekel (Victron Energy Staff) ♦♦ ·

Thanks for the help, I decided to install an external solar panel switch so that it would be possible to turn off the voltage from the panels to mppt, so that they would not give out voltage when the system is turned off. Connection with BMS is lost when I disconnect it, but since mppt continue to work, they see that it has disappeared from the network and give an error on the monitor. In the future I will use the signal from bms to turn on the relay, which will turn on, turn off the output from mppt.