This type of battery is easily identified by the screw caps on top of the battery.

The flooded lead acid battery has cells using positive plates of lead oxide and negative plates of porous 'spongy' lead alloy. The electrolyte is a sulphuric acid solution and must be handled with care as it is extremely corrosive, usually 35% sulphuric acid and 65% water.

The unsealed / flooded type battery is most commonly used in cars because they are designed to provide a very high current for brief periods of time, such as starting an engine.

These batteries do not like being discharged right down (ie. to say around 30% of charge) and will eventually fail if used in this manner. A deep cycle battery is better suited to long discharge cycles.

This type of battery is completely sealed, and therefore often referred to as maintenance free.

The deep cycle type is designed to continuously provide power for long periods of time (for example in a golf cart or other battery electric vehicle). They are ideal when used to store energy from a solar array or a small wind turbine . They usually have thicker plates in order to have a greater capacity and survive a higher number of charge/discharge cycles.

A SLA battery is suited to long discharge cycles, and can routinely be discharged down to 20% of full charge with no deterioration of the battery.

Use the formula (Ah) divided by 10 to calculate the required charge rate for a SLA battery, this is based on a charge time of 14 hours.

The maximum charge rate for a SLA battery should be no more than (Ah)/5.

Sealed lead acid batteries should not be discharged below 11V, as this can lead to permanent damage.