Hey folks! I'm trying to set up a mini solar system to charge USB devices, but I'm hitting some roadblocks. I live in a historic building, so I don't have the option to install solar panels on the roof or anything visible. Fortunately, I found a 20 cm space by my window where I can place a couple of small panels that are out of sight. Right now, I have two 6V 1W panels that I connected in parallel and a 12V 3W panel from a different brand. I'm using MP1584 buck converters for each pair of panels, set to output 5.2V, and I have diodes to prevent backflow. I've got a multimeter showing the voltage at 5.2V, but when I connect it to a power bank, the voltage drops to 3.8V. There's no direct sunlight today, but it's not cloudy either. What am I doing wrong? I appreciate any insights!
1 Answer
It sounds like your power bank is trying to pull too much current. A typical USB power bank needs at least 10W, but your setup can only deliver about 5W max under ideal conditions. Even in full sunlight, you might only get around 2 watts effectively, considering that your 6V panels combined will not exceed the output of the weakest panel. You might need to reconsider what devices you're trying to charge or maybe look for a power bank that has lower input requirements.
Is there any way to get a steady 5V even if the current is low? I just want to recharge some batteries, but rushing isn't an issue for me.