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SPECIFYING LEAD ACID BATTERIES AND CHARGERS
FLOODED / WET CELL AND SLA (SEALED LEAD ACID) BATTERIES
There are two categories of lead acid batteries – Flooded/Wet Cell and Sealed Lead Acid
(SLA). A flooded/wet cell battery has a high tolerance to overcharging. However, it will
release hydrogen gas when charging that must be properly vented and the water level
must be checked frequently. SLA batteries can either be Gel Cell or AGM (Absorbed
Glass Mat). Both the Gel Cell and AGM are maintenance free, have no liquid to spill and
gassing is minimal. The Gel Cell is the least affected by temperature extremes, storage at
low state of charge and has a low rate of self discharge. An AGM battery will handle
overcharging slightly better than the Gel Cell
Lead-acid batteries can be categorized by the type of application: automotive service -
Starting/Lighting/Ignition (SLI, a.k.a. cranking) and Deep Cycle service
SLI BATTERIES
Everybody is familiar with the SLI batteries that are used for automotive starting and
powering vehicular accessories. SLI batteries are designed to produce high power in short
bursts but must be constantly recharged (normally with an alternator while driving).
Vehicle starting typically discharges 1%-3% of a healthy SLI battery's capacity.
The automotive SLI battery is not designed for repeated deep discharge where up to 80 %
of the battery capacity is discharged and then recharged. If an SLI battery is used for this
type of application, its useful service life will be drastically reduced
DEEP CYCLE BATTERIES
Deep cycle batteries are designed with thick-plate electrodes to serve as primary power
sources, to have a constant discharge rate, to have the capability to be deeply discharged
up to 80 % capacity and to repeatedly accept recharging. They are marketed for use in
recreation vehicles (RV), boats and electric golf carts – so they may be referred to as RV
batteries, marine batteries or golf cart batteries. There are two categories of deep cycle
lead acid batteries – wet and sealed. A wet cell battery has a high tolerance to overcharg-
ing. However, it will release hydrogen gas when charging that must be properly vented
and the water level must be checked frequently. Sealed batteries can either be Gel Cell or
AGM (Absorbed Glass Mat). Both the Gel Cell and AGM are maintenance free, have no
liquid to spill and gassing is minimal. The Gel Cell is the least affected by temperature
extremes, storage at low state of charge and has a low rate of self discharge. An AGM
battery will handle overcharging slightly better than the Gel Cell
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