DIY MPPT solar charge controller – #2 – testing on a solar panel

Hi there! Welcome to my second video about the MPPT solar charge controller I build. The warm and sunny weather today give me a great opportunity to test the device on an actual solar panel. For a few dollars and free shipping of course, I ordered a 10W solar panel from China. I soldered a couples of wires to the back of the panel to connect to the MPPT controller. I connected the solar panel to a multimeter to measure the open-circuit-voltage. With this I can guess where to expect the maximum-power-point. For the 10W panel I figured, a 5W 12V car light might be a nice load. It should be able to power the light with room to spare. When connected to the panel, I can see the light is on, yet not ass bright as I expected.

The voltage over the light bulb also is quit low. Either the lamp isn't 5W or the panel isn't 10W. Given my previous Ebay experiences, I suspect the panel not to be as powerful as it was advertised. I connected the controller to my PC so i can program it with a UsbAsp programmer I have. I program the output voltage to be at most 12V, so it matches the car light. The meter on the left shows the panels voltage. The one on the right shows the output voltage of the controller. I seems the controller is having trouble getting the output voltage to 12V. Now I hook up the load to see how the controller handles that. The voltage on the input only drops to 15V or roughly 80% of open-circuit-voltage, which is close to the maximum-power-point. I am happy this part of the circuit works as I intended. The output voltage however is slightly lower than without the controller, but the lamp is glowing nevertheless. The final test will be to measure the temperature of the mosfet. I have put a temperature probe between the fins of the heat-sink. So the starting temperature is about 42C.

It does not seem to rise at a dramatic rate, so that works great as well. Well then, I guess the parts that need improving the most are efficiency and the buck-boost-output stage. Have a great day and like, share and subscribe if you like this video..

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