SLA Batteries

A gel battery (also known as a "gel cell") is a VRLA battery with a gelified electrolyte; the sulfuric acid is mixed with a silica fume, which makes the resulting mass gel-like and immobile. Unlike a traditional wet-cell lead-acid battery, these batteries do not need to be kept upright (though they cannot be charged inverted). These batteries are often colloquially referred to as sealed lead-acid (SLA) batteries due to their non-leaking containers, but they are not completely sealed; the valve regulation system allows for gas to be expelled.