sla battery charging require ments.

[mark krawczuk]

hi, how can i work out the float charging requirements for a :
12 v sla
and

6 volt sla

mark

 

[glenbadd]

On Sep 27, 4:32 pm, "mark krawczuk" <krawc...@adam.com.au> wrote:

hi, how can i work out the  float charging requirements for a :
12 v sla
and

6 volt sla

mark

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.

 

[Mr.T]

"glenbadd" <glennbaddeley@yahoo.com.au> wrote in message
news:92dcd461-3cd3-45ee-9460-e89d3587c6fc@b14g2000pro.googlegroups.com...
On Sep 27, 4:32 pm, "mark krawczuk" <krawc...@adam.com.au> wrote:

hi, how can i work out the float charging requirements for a :
12 v sla and 6 volt sla

}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. <5% of
the rated capacity is usually a fairly safe maximum float charge.

MrT.

 

[James]

"mark krawczuk" <krawczuk@adam.com.au> wrote in message
news:vPednRUnLLz6pz3RnZ2dnUVZ_tSdnZ2d@adnap.net.au...

hi, how can i work out the float charging requirements for a :
12 v sla
and

6 volt sla

mark

Just been through all this myself and thought you might find this useful.
www.jaycar.com.au/images_uploaded/slabatts.pdf

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

 

[Charlie+]

On Mon, 27 Sep 2010 16:02:37 +0930, "mark krawczuk" <krawczuk@adam.com.au>
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+.

hi, how can i work out the float charging requirements for a :
12 v sla
and

6 volt sla

mark

 

[Tom]

On 29/09/2010 5:53 PM, Charlie+ wrote:

On Mon, 27 Sep 2010 16:02:37 +0930, "mark krawczuk"<krawczuk@adam.com.au
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

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

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+.

hi, how can i work out the float charging requirements for a :
12 v sla
and

6 volt sla

mark

 

[Grant]

On Wed, 29 Sep 2010 22:31:23 +1000, Tom <tom@no.spam.invalid> wrote:

On 29/09/2010 5:53 PM, Charlie+ wrote:
On Mon, 27 Sep 2010 16:02:37 +0930, "mark krawczuk"<krawczuk@adam.com.au
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

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

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.

 

[glenbadd]

On Sep 28, 4:02 pm, "Mr.T" <MrT@home> wrote:

"glenbadd" <glennbadde...@yahoo.com.au> wrote in message
}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. <5% of
the rated capacity is usually a fairly safe maximum float charge.

MrT.

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.

 

[who where]

On Wed, 29 Sep 2010 16:36:49 -0700 (PDT), glenbadd
<glennbaddeley@yahoo.com.au> wrote:

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.

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.