To test voltage, set your multimeter to read AC voltage. If it reads 60–80 % of rated, a bypass diode has failed. If Voc is normal but the system is not producing, the problem is downstream. Testing solar panels is easy with a multimeter! To test the current, simply connect the multimeter to the panel's output. Connect the multimeter. 🔋 Learn how to test solar panels using a multimeter — step-by-step! I'll show you how to safely check voltage, amperage, and open-circuit power, so you can confirm if your panels are producing the watts you expect. Perfect for DIY solar builders, RV owners, o. Always use caution when testing voltage.