I have a Deye 8kW inverter with 1 off US3000 and 1 off US3000C batteries installed with the US3000C as the master. My baseload during the night varies from 400W to 900W. What is warrying is that the SOC drops from about 40% to about 20% in 10 minutes without any change in load. The rest of the time the drain rate is about 10% per hour. What can be the problem?