The open circuit initial test of a newly purchased solar panel immediately tells you if there are obvious flaws or damage to the panel resulting in terrible performance. It is NOT a vigorous test of the panel’s manufacturer’s rating in terms of output. This will tell you if there is mechanical failure such as a bad diode or failed solder joint. You should see a minimum of 19V and 750mA open circuit (on a cloudy day) and over 20V and 4A on a sunny day, for a 160 watt rated panel.
Post time: Feb-11-2017