Review on 🌞 SUNSUL 20W 12V Solar Panel Kit Battery Maintainer Trickle Charger, Waterproof 5A 12V/24V PWM Solar Charge Controller, Adjustable Mount Bracket – 20 Watt with Accessories by Johnny Mcnealy

The solar panel out of the box put out zero volts in the sun. I needed it the next day so I started troubleshooting. I removed the plastic cover from the wire bracket on the back of the solar panel and saw the problem. There is a large cylindrical resistor near the plastic cover latch. The latch hangs down and needs space underneath to move. The resistance is large and above the locking cap. When the lid is opened or closed, the latch hits the resistance and pushes it down a bit. On my solar panel, a latch pushing down on a resistor caused a bad solder joint that came loose. The end result was an open circuit and a dead solar panel. I disassembled it, cleaned of old solder and re-soldered. Now it works fine. So this relatively cheap solar panel cost me almost twice as much as I had to buy a soldering iron and lead-free solder. And I wasted 2 hours of my life on bad resistor placement design and bad soldering. If they're really testing this stuff (it has a QC sticker on it) then they should be testing it with the cap off, then break the resistance when the cap is on.