A 250W solar panel can charge a 100ah gel battery in 5 hours with clear skies. If you have never used this method before, the recharging process is actually easy. The basic steps are as follows. Plug the. To charge a battery with solar panels, ensure they are placed in a location with maximum sunlight exposure, mount the panels at the optimal angle, and connect a solar charger. For gel batteries, use a charger with a voltage regulator and current limiter, with a voltage between 2. This gel-like substance, formed by combining sulfuric acid with silica, enhances battery performance and longevity. Batteries are the heart of any solar system, storing sunshine during the day, so you can use that power whenever you need it.