My WhizBang Jr, and my 500A/50mv shunt equipped SMA SI6048 badly disagree

[Trukinbear]

The SOC figures vary greatly occasionally requiring my intervention to keep from badly overcharging my battery.

The SI6048 supposedly receives data gleaned from my WhizBang Jr via one of my 2-networked Classic 250 charge controllers via my MODBUS/Canbus adaptor.

The WhizBang Jr (and subsequently both of my MidNite Classic 250's) gives a much higher SOC reading than what the SI6048 thinks.

I've double-checked my wiring inside the MidNite SMA-OG E-panel to verify that the output from the solar goes to the bus on the Inverter side of the 500A/50mv shunt (and attached WBJR). Here is where I've narrowed what I think is causing the problem down to:
The WhizBang Jr, and the SI6048's current readings (supposedly from the WBJR but looks like just from the shunt) are spot on (after calibrating the shunt) about power in or out of the batteries with no solar. With solar the WBJR shows the additional current in from the controllers, but the SI6048 still reads the value minus the current from the controllers. This makes the SOC calculations WAY OFF from each other... Often the WBJR will show I'm at 80% SOC with only like -140 net AH, but the SI6048 thinks we're at 40% and wants to run the generator.

What have I missed?

 

[madsci1016]

Just say this looking at 6048 posts. If I assume the SI6048 is in lead acid mode, it calculates it's own SoC based on a complex and proprietary. I've tried my best to characterize it, before giving up and making my own BMS solution for it.

The fact that it can't read your solar charge controller current concerns me. Are you sure it's wired correctly so the shunt sees solar charge current?

 

[Trukinbear]

Just say this looking at 6048 posts. If I assume the SI6048 is in lead acid mode, it calculates it's own SoC based on a complex and proprietary. I've tried my best to characterize it, before giving up and making my own BMS solution for it.

The fact that it can't read your solar charge controller current concerns me. Are you sure it's wired correctly so the shunt sees solar charge current?

Yes, it is wired via MODBUS/Canbus comm adaptor to communicate directly between the 2 Classic 250s and the SI6048 and while the Classics themselves are wired to the shunt (via WhizBang Jr) the SI6048 is not, and takes its data from the Classic 250's which in turn are controlled by the SI6048. My original mistake was wiring the SI6048 to the shunt AND the Classic 250's - has to be one or the other. Working great now.