Set your multimeter to DC Amps (A). Connect the probes the same way as before — red to +, black to −. A 200W 12V panel might show. Testing solar panels is easy with a multimeter! To test the current, simply connect the multimeter to the panel's output. Connect the multimeter. Learning to test a solar panel with a multimeter is an investment in your knowledge and ability to manage your own solar energy system or provide valuable services in the growing solar industry. Measure Voc (open circuit voltage) — if it reads 0V, the panel or wiring is dead. Perfect for DIY solar builders, RV owners, o.