@Eric-Katzfey
I'm not sure what may have changed, before when setting BATT_MONITOR to 21 the param would write but we wouldn't get the additional parameters that that setting should have enabled. Last week I tried it again to reply to your last message and we got the BATT_I2C_BUS parameter and were able to get it all working. Gotta love when things seem to magically fix themselves, thanks for the support.
PS, we have built a parallel system on the latest SDK and will be migrating the current one over to match.