Dear Experts
I have a small issue with my back-up system.
I recently upgraded my installation from lead-acid to a 21kWh Pylontech system.
Everything is running well and I am very pleased so far.
However, since the main system runs our off-grid house I also installed a little 24V backup system with my old lead-acid batteries, two 220W panels in series and a 75/15 MPPT smart charger.
I also wanted to use my old BMV 712, which I don’t need anymore, since I installed the Pylontech US3000C batteries and have them managed by its own BMS.
I connected the BMV712 as well as the MPPT to the same Cerbo (VE.direct) that my Pylontech batteries are connected to.
The BMV also measures mid-point voltage since I have a battery-equalizer installed.
The idea was to be able to monitor both systems (Pylontech and led-acid) via VRM
The problem.
As soon as I connect the 75/15 MPPT via VE.direct to the Cerbo the charger stops working. Normal voltage, but no current.(and a little warning that the charger has been disconnected for protection)
BMV712 displays battery voltage and SOC as usual
If I then disconnect the MPPT from the Cerbo and remove the “controlled by BMS” feature, in the MPPT the charger jumped back into action as if nothing happened, but of course the data is no longer displayed on the VRM
Hence my questions: Is the Cerbo capable of managing and displaying two separate (monitoring) systems or is the Pylontech BMS trying to regulate my back-up system as well, which would be an explanation for the trouble.
Any input is appreciated
Thanks