How to disable voltage sensing when MPPT and BMV712 are connected by VE Direct?
The Issue occurs when charging the aux battery only and the house battery is isolated from the charger (MPPT). The aux battery will be overcharged due to VE direct will read voltage for the house battery. Voltage sens must be disabled.
The charger is solar i.e. the MPPT is controlling.
The solar will start to charge lithium. A relay will isolate lithium when full and MPPT will continue to float charge the aux battery only. However, when MPPT is connected by VE direct (as well as BMV712 and GX device), the MPPT will get voltage from the lithium battery (house battery connected to B1 on the shunt) and due to no charger on the house battery, the voltage will be low, why MPPT will increase voltage to compensate as it believes there is a voltage drop. This will result in overcharging of the aux battery.
Other chargers with sens wire connected to the aux battery works fine. If the VE Dir cable is unplugged from MPPT, charging works fine as well, however no other data from MPPT.
The issue is that it seems not possible to set disable voltage sens for the MPPT.
I believe Victron has missed this setting i.e. a bug.
Appreciate any idea how to disable voltage sens.
Why would you not just float the house battery? If you don't want to float it, then set the rebulk offset to allow the battery voltage to drop down again before beginning another charge cycle.
