Review on ⚡️ Schumacher Solar Charge Controller 12V - Optimize Lead-Acid Batteries and Solar Panel Performance by Jeffrey Dunn

I use this with a 12v 2.4w solar panel to keep the RV engine battery charged when in storage. The solar panel didn't have a built-in controller, so they bought one to make sure the voltage was checked before getting to the battery. It is plugged into the cigarette lighter socket and then the solar panel is connected to it. Works very well. The battery remains charged.