Deep Cycle Batteries are designed to be discharged down as much as 80% time after time, and have much thicker plates.

The major difference between a true Deep Cycle Battery and others is that the plates are SOLID Lead plates – not sponge.

Sealed Batteries also called Maintenance Free Batteries are made with vents that (usually) cannot be removed. . Sealed Batteries are not totally sealed, as they must allow gas to vent during charging. If overcharged too many times, some of these batteries can lose enough water that they will die before their time.

Gelled Batteries or “Gel Cells” contain acid that has been “gelled” by the addition of Silica Gel. Thereby turning the acid into a solid mass that looks like gooey Jell-O. The advantage of these batteries is that it is impossible to spill acid even if they are broken. However, there are several disadvantages. One is that they must be charged at a slower rate (C/20) to prevent excess gas from damaging the cells. They cannot be fast charged on a conventional automotive charger or they may be permanently damaged. This is not usually a problem with solar electric systems, but if an auxiliary generator or inverter bulk charger is used, current must be limited to the manufacturers specifications.

A newer type of sealed battery uses “Absorbed Glass Mats”, or AGM between the plates. This is a very fine fibre Boron-Silicate glass mat. These type of batteries have all the advantages of gelled, but can take much more abuse. We sell the Concorde (and Lifeline, made by Concorde) AGM batteries. These are also called “starved electrolyte”, as the mat is about 95% saturated rather than fully soaked. That also means that they will not leak acid even if broken.