Samlex America SCC-30AB - Manuel (Page 11)

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GENERAL INFORMATION: BATTERIEs
Sealed / VRLA batteries are designed to recombine the Hydrogen and Oxygen back
into water and hence, Sealed / VRLA batteries are not required to be topped up with
distilled water. That is why, these batteries are also called maintenance free batteries.
Sealed / VRLA batteries use safety valves to release any excessive gas pressure built
up inside the battery due to malfunction or overheating. If this happens (e.g.,
by overcharging) the valve vents the gas and normalizes the pressure, producing
a characteristic acid smell. Valves can sometimes fail however, if dirt and debris
accumulate, allowing pressure to build up that will result in damage to the battery.
Sealed Lead Acid (SLA) or Valve regulated Lead Acid (VRLA) Batteries
Sealed Lead Acid (SLA) batteries or Valve Regulated Lead Acid (VRLA) batteries can
either be Gel Cell or AGM (Absorbed Glass Mat). In a Gel Cell battery, the electrolyte
is in the form of a gel. In AGM (Absorbed Glass Mat) battery, the electrolyte is soaked
in Glass Mat. In both these types, the electrolyte is immobile. There are no refill caps
and the battery is totally sealed. Hydrogen and Oxygen released during the charging
process are not allowed to escape and are recombined inside the battery. Hence, there
is no water loss and the batteries are maintenance free. These batteries have safety
valves on each cell to release excessive pressure that may be built up inside the cell.
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.
Non Sealed (Vented / Flooded / Wet Cell) Lead Acid Batteries
In a non-sealed / vented / flooded / wet cell battery, each individual cell compartment
has a refill cap that is used to top up the cell with distilled water and to measure
the specific gravity of the electrolyte using a hydrometer. When fully charged, each
individual cell has a voltage of approximately 2.105V and electrolyte specific gravity
of 1.265. As the cell discharges, its voltage and specific gravity drop. Thus, a healthy,
fully charged, 12V nominal battery with each of the 6 cells fully charged to 2.105V
will measure a Standing Voltage of 12.63V at 25ºC / 77ºF. Also, in a healthy battery,
all the individual cells will have the same voltage and same specific gravity. If there is
a substantial difference in the voltages (0.2V or higher) and specific gravities of the
individual cells, the cells will require equalization.
sLI (starting, Lighting, Ignition) Batteries
Everybody is familiar with the SLI batteries that are used for automotive starting,
lighting, ignition and powering vehicular accessories. SLI batteries are designed to
produce high power in short bursts for cranking. SLI batteries use lots of thin plates
to maximize the surface area of the battery for providing very large bursts of current
(also specified as Cranking Amps). This allows very high starting current but causes
the plates to warp when the battery is cycled. 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