by Vspec » Fri Jun 21, 2019 6:03 am
A few weekends ago, I was playing around with my setup with the two panels (100w, 5.5a,18v) connected in parallel at the controller (500w, 30a, 18v PWM). I was getting very sun exposure. I was outputting enough amp to even run the highly inefficient thermoelectric cooler off the load terminals. My tiny 35ah AGM battery reached float fairly quickly.
I got curious and stuck the multi-meter on the inputs for the solar panels at the controller and was getting between 21v-22v. The case of the controller was not overly in spite of sitting directly in the sunlight. If I did turn on the load, the input voltage would drop to 17v-18v.
What is going on here? It would be quite suspect that each panel would be able to produce more than their specified amperage. None of the panel were fused. The final install would be fused for the max amp of the controller.