The composition of gel batteries is very similar to a flooded battery. Alternating lead and lead oxide plates are immersed in an electrolyte. The major difference is the electrolyte: in a gel battery, silica is added to stiffen the electrolyte fluid. This means gel cell batteries are all maintenance-free. The gelled electrolyte means gel batteries are safer to use and can be mounted in virtually any orientation (except upside down) without a danger of spillage. They are better lasting in hot weather and can tolerate very deep cycle operation.