With NiFe, you cannot use any state of charge meter, the battery voltage is way too variable. If all you can manage is 1.66Vper cell, then, that's all you can do. My inverter (xw-6048) can only charge up to 64V, but it does not fault until 67.5V So, my solar charge controllers get the daily voltage up, and I have a couple hours of absorb on them before dropping back to float. Winter (cloudy weather) I'm much lower in the voltage curve and can only charge to 64v until the sun returns. Then the battery sucks power from the PV for hours before it gets to absorb.Does your inverter automatically ramp up the daily voltage or do you manually have to increase the charging rate during the day?I have not found a setting for the Sunny Island to do thsi. It seems to set on Float and the SOC needs to drop below 80% before a boost charge is automatically applied. Wondering if anyone has their Sunny Island to increase volatage during the day and return to float at night?