I have a 5kw Sunsynk hooked up to two 5kwh LiFePower batteries. Due to an issue with the firmware on the batteries, they currently want to charge to 60V bulk - not great for a 16s battery! 3.75V per cell... so I've tried setting the voltage in battery settings to 56V which is a charge value I'm much happier with. Unfortunately it seems the Sunsynk ignores this and follows the BMS recommended value instead if I set the charge SOC to 100%. I've seen as high as 58.8V before turning off charging.

I've gotten around this for now by having SOC at 97% - so it stops charging before the voltage gets very high. My concern is that once my solar panels are installed, the Sunsynk will try and charge to 100% anyway and then the 60V will be an issue.

Is it correct that the inverter will ignore my battery settings in favour of the BMS requested voltage? And is there anyway to stop solar charging the battery to 100%?

I'm hoping for a firmware update from the battery manufacturer to sort out the voltage issue but until then it would be nice to set the voltage lower on the inverter.

1 hour ago, JaseZA said:

I have a 5kw Sunsynk hooked up to two 5kwh LiFePower batteries. Due to an issue with the firmware on the batteries, they currently want to charge to 60V bulk - not great for a 16s battery! 3.75V per cell... so I've tried setting the voltage in battery settings to 56V which is a charge value I'm much happier with. Unfortunately it seems the Sunsynk ignores this and follows the BMS recommended value instead if I set the charge SOC to 100%. I've seen as high as 58.8V before turning off charging.

I've gotten around this for now by having SOC at 97% - so it stops charging before the voltage gets very high. My concern is that once my solar panels are installed, the Sunsynk will try and charge to 100% anyway and then the 60V will be an issue.

Is it correct that the inverter will ignore my battery settings in favour of the BMS requested voltage? And is there anyway to stop solar charging the battery to 100%?

I'm hoping for a firmware update from the battery manufacturer to sort out the voltage issue but until then it would be nice to set the voltage lower on the inverter.

You could always just unplug the BMS comms cable and set battery voltages manually on the sunsynk. Set a nice 58.4V as bulk charge and 54.4V float. 48V cutoff.

True - although it will be unfortunate not having SOC for my automations. I guess I'll call on the battery supplier for a firmware update some more! The other option is I follow what some others have done here and do the BMS comms to inverter myself with a raspi and modify the CAN signals for charge voltage.