> Mike Harrison wrote:
>
> > >Important! Most of the "electronics" style SLAs
> > >have a very low max charging current, this is an
> > >important spec and often written on the battery.
> > >Exceeding this charging current is very bad for
> > >the battery and it's life expectancy. If possible
> > >use a constant current battery charger.
>
> > I think the 'official' spec is often current-limited constant voltage
> > rather than constant current
>
>
> Most of the new SLA batteries have a "initial current"
> spec, usually written on the battery. This is about 25%
> of the capacity, so a 10A/h battery has initial current
> 2.5A, etc. This is the MAX current that you can use to
> charge the battery.
> -Roman
>
Quality SLA Battery Chargers are three stage chargers

Stage one - The battery is charged at a constant current until the battery
terminal voltage reaches a predetermined voltage (manufacturer and
temperature controlled).

Stage two - The battery continues to be charged at that constant voltage
until the current tails off to the float current.

Stage Three - The float current is maintained.

An incorrect charging regime will cause the valves to open as the gasses
will be unable to re-combine faster than the generation rate. Acid soaked
glass mat batteries are better in this regard and allow faster charge rates
as the gasses permeate through the matting faster than they can through gel.
Venting can be considered a terminal condition.

Regards

Chris Carr

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