Deep Cycle Batteries

Deep cycle batteries are designed to provide steady power over an extended length of time. This is in contrast with high cycle batteries which provide a large burst of power over short length of time. Deep cycle refers to the battery’s ability to discharge most of its capacity before needed to be recharged.

Lithium and lead acid batteries can have deep cycle capabilities. Lead acid batteries can be flooded or sealed. Sealed batteries are commonly known as VRLA (Valve Regulated Lead Acid) and SLA (Sealed Lead Acid). VRLA batteries can either be Absorbed Glass Mat (AGM) or gel cell.

Flooded lead acid batteries have a usable capacity up to 50%. This means that 50% of the battery’s total capacity can be used before it must be recharged. The charging efficiency is approximately 70-85%. Although affordable and tolerant of overcharging, flooded lead acid batteries have a shorter lifespan than other battery types. They also require maintenance, proper ventilation and must remain in an upright position.

AGM batteries have a usable capacity of 80% and a charging efficiency of 95%. They are more expensive than flooded lead acid batteries and are sensitive to overcharging, however, they are maintenance-free, fast-charging and position insensitive.

Gel cell batteries have a useable capacity of 75% and a charging efficiency around 85-90%. They are more expensive than flooded lead acid and AGM batteries and cannot tolerate fast charging or overcharging. They are maintenance-free, have a high heat tolerance and are position insensitive.

Lithium iron phosphate batteries have a useable capacity of 80-100% and have the fastest recharge rate. They have an extremely long cycle life and provide constant voltage over any rate of discharge. They are much more expensive than lead acid batteries and require a battery maintenance system.