sla battery charging require ments.

hi, how can i work out the float charging requirements for a :

12 v sla and

6 volt sla

mark

Reply to
mark krawczuk
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Its usually printed on the battery, or consult the manufacturers data sheet.

A 12V SLA can usually be float charged at constant voltage 14.2 - 14.4 volts without the battery gassing off. A 6V battery at half that.

HTH, G.

Reply to
glenbadd

}Its usually printed on the battery, or consult the manufacturers data }sheet.

Not often on the battery IME, but the data sheet is the thing to check.

}A 12V SLA can usually be float charged at constant voltage 14.2 - 14.4 }volts without the battery gassing off. A 6V battery at half that.

I wouldn't want to "float charge" at that level personally. 13.2-13.8V should be sufficient if you want the battery to last on float. You also need some current limiting as well for when the battery is flat or dies.

Reply to
Mr.T

Just been through all this myself and thought you might find this useful.

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Google "sla charger" "sla gassing voltage" and the like to find all the other good info, there is heaps around. How complex you need make it really depends on the environment and how well you want to look after the batteries.

James

Reply to
James

On Mon, 27 Sep 2010 16:02:37 +0930, "mark krawczuk" wrote as underneath my scribble :

Contrary towhat the data sheets tell you - if you are interested in the longevity of the batteries rather than the absolute stuffed peak capacity charge - use the float voltage of 13.2v. At this float the batt will still gas off but at a very very slow rate - this should allow you to add only a few ml of D water to dampen the plate pads every two years after doing it when bought new - I have found this the optimum and without this care do not expect your batts to last more than about two years in warmer conditions, about three years in cooler conditions and also retain high capacity. Expect eleven years and counting with. The mfgs dont make this type of care that easy - you have to have the nouse to break into the batt safely and put it back together so that the breather caps cant get pushed off etc.... have no experience with 6v float batts but you could interpolate!.. C+.

Reply to
Charlie+

S in sla stands for sealed - it's pretty hard to add any water...

Reply to
Tom

And these days they're 'Valve Regulated' --> +/- 5 atmospheres sealed ;)

Not supposed to lose water in normal circumstances. Anyway it's not direct water loss, it's the failure to recombine hydrogen and oxygen back to water under 'normal' operation.

Grant.

Reply to
Grant

eed

Yeah, sorry. I was thinking of very simple current limited + voltage limited recharging of a 12V batt and letting it float for a day or so before I come back and switch off the charger. Long term float should be at a lower voltage, as you suggest.

G.

Reply to
glenbadd

If you really want a decent charge arrangement that tends to the proper care and feeding of SLA/VRLA batteries, google for SLUA115.pdf and discover one of the better charge controller chips. Very simple chargers based on this were in the local electronics mags and available as kits from the usual suspects.

Reply to
who where

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