Smart Solar MPPT Charger Relay not activating for float condition

DIY
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1

I have been trying to configure my 2 SmartSolar MPPT chargers so that one charger provides a closed relay on SOLAR, and the second provides
a closed RELAY on FLOAT condition. Useing these relays in series I want to trigger our car charger to boost. This way when batteries FULL and SOLAR power available I can BOOST car charge at midday for 1 hour.

I can never get (either of) the MPPT Charger to create a closed relay for FLOAT condition. Wondering if this is a bug in firmware?

My system configuration is as follows:

MULTIPLUS II 8K

SMartSolar MPPT Ve CAN 250/100 ( 6 panels)
SmartSOlar MPPT Ve CN 150/70 ( 3 panels )

Gerber GX

Pylontech Batteries 2x 5000 + 4 x 3000

Float voltage on the chargers is set to 51V which is achieved when batteries full. But I am wondering if because the setup is BMS controlled.

Does anyone have any ideas on this?

Thanks

Rob

2

With your setup, the MPPT’s are under external control by the BMS. This will usually not let them go into the float mode, so the relay won’t close.
I’ts far better to try to do this with a node red flow that senses the MPPT charge mode over the VE-direct link. Once this goes into the cc/cv mode (normally in MPPT mode), it can be assumed that the batteries are approaching full charge, and the SOC is >90%. You should also be able to read the soc from the BMS directly, and use that as a trigger.