I am troubleshooting my new solar setup which includes a Smart Solar 100/30 charge controller. Victron's Pre-RMA Test instructions say to check for a PV Input short, but don't indicate what the actual reading should be. I tested two units side by side with a basic digital multimeter. Both units were completely disconnected from all other sources. Neither indicated a short (i.e. resistance value was > 0), but the readings of the PV input were different between the two units:
Unit 1: value changes continually during the reading, which implies there is some capacitance or inductance as part of the PV input circuit
Unit 2: the reading instantly provided a constant value and did not change
I suspect that unit 1 is faulty, but I would like to know what the PV resistance measurement should be. Anybody have a working 100/30 lying around that they can check, or does Victron have a detailed technical spec that shows what the resistance value should be?
SOLVED
My problem was a faulty MPPT (Unit 1). Unit 1 was the controller whose PV resistance measurement was constantly fluctuating. Unit 2 had a constant reading and worked properly in my solar setup. So, if your PV voltage value is dropping to zero when connected to the MPPT PV inputs, be suspicious of your MPPT unit.
