A Gel battery design is typically a modification of the standard leadacid automotive or marine battery. A gelling agent is added to the electrolyte to reduce movement inside the battery case. Many gel batteries also use oneway valves in place of open vents, which help the normal internal gasses to recombine back into water in the battery, reducing gassing. Generally, gel batteries are less tolerant of high heat and are charged at lower power than traditional or AGM batteries ... Read more