I've read so much my head is spinning and I'm still not completely sure what size solar charge controller to buy. We have 8- 100 watt panels, each panel has VMP (volts) of 20.6 & IMP (amps) of 4.85. We are wiring them in sets of 2, in series, which brings the VMP to 41.2 and the IMP to 4.85...