Victron CerboGX programming for decreasing amperage in charge


New Member
May 6, 2021
Hi all,

I'm fiddling around with Victron ESS (Energy Storage System).

One of the 'issues' I was having, is that is was pushing full charging watts to the battery, which has a BMS not connected to the Victron system. This could result into the BMS disabling charging because cells would get unbalanced when nearing full charge.

Perhaps useful to others; the CerboGX has a mode which includes Node-RED. Using that, I was able to throttle the charge wattage when it hits a certain voltage. Here's an example: at first, the charge is using constant current (wattage), set to about 36A. When the voltage rises above 27.6v, the wattage will be throttled.

As you can see, the charge wattage goes down while keeping the voltage high enough for decent charging.


This is the Node-RED flow: I'm combining 3 values, the battery voltage, current charge wattage and "grid setpoint" (maximum in/out wattage to the grid). Sadly, there's no Victron integration to set the max charge wattage, so I'm using "mqtt" protocol for that.

The "join" node combines the 3 values, the "change charge wattage" node check the voltage and current wattage and modifies the wattage if required, decreasing it by steps of 50w.


I watched it throttle down the max charge wattage several times now, seems to work correctly.

With regards,

I notice no one has answered. I hope you had some luck in figuring it out.
Well, it seems to work so far. I posted it as a suggestion for people to read on how to throttle charging when there's no connection between BMS and Victron MultiPlus. ;)