I took a battery out of an emergency power system in a shop recently.
I want to use it to power a headlamp bulb. So how do I go about
charging it with a 12v transformer?

I have two wires and a choice of jack plugs to try and connect them
to. Or do I just pull the socket off the regulator and connect them
with a couple of clips?

Weatherlawyer wrote:
I took a battery out of an emergency power system in a shop recently.
I want to use it to power a headlamp bulb. So how do I go about
charging it with a 12v transformer?


You don't.

Buy a 12v battery charger.

On Jun 10, 7:45 pm, JohnW wrote:
JohnW, in article MPG.20d64a3e509a9bbb9897f8
@news.aaisp.net.uk, says...

You'll need more than 12v if they are sealed lead-acid,

http://preview.tinyurl.com/2359m9

It looks like the little one he
http://www.maplin.co.uk/images/Full/MM22Y_MM26D.jpg
Thanks.

So which way around do the jacks go? (Assuming I can still find them.)
I've got one of those Maplin's PW0140 Regulator Power Supply jobs the
kind that will work on 3, 6, 9 or 12 volts.

"Weatherlawyer" wrote in message
ups.com...
On Jun 10, 7:45 pm, JohnW wrote:
JohnW, in article MPG.20d64a3e509a9bbb9897f8
@news.aaisp.net.uk, says...

You'll need more than 12v if they are sealed lead-acid,

http://preview.tinyurl.com/2359m9

It looks like the little one he
http://www.maplin.co.uk/images/Full/MM22Y_MM26D.jpg
Thanks.

So which way around do the jacks go? (Assuming I can still find them.)
I've got one of those Maplin's PW0140 Regulator Power Supply jobs the
kind that will work on 3, 6, 9 or 12 volts.

You need more than 12v to charge a 12v battery.

Just use one of these
http://tinyurl.com/332a8o

Sparks...

"Sparks" wrote in message
...

"Weatherlawyer" wrote in message
ups.com...
On Jun 10, 7:45 pm, JohnW wrote:
JohnW, in article MPG.20d64a3e509a9bbb9897f8
@news.aaisp.net.uk, says...

You'll need more than 12v if they are sealed lead-acid,

http://preview.tinyurl.com/2359m9

It looks like the little one he
http://www.maplin.co.uk/images/Full/MM22Y_MM26D.jpg
Thanks.

So which way around do the jacks go? (Assuming I can still find them.)
I've got one of those Maplin's PW0140 Regulator Power Supply jobs the
kind that will work on 3, 6, 9 or 12 volts.

You need more than 12v to charge a 12v battery.

Just use one of these
http://tinyurl.com/332a8o

Sparks...

and how many watts is the bulb, because if it is a 55w bulb, it will
probably last for 5-10 minutes on that battery!

In article . com,
Weatherlawyer wrote:
On Jun 10, 7:45 pm, JohnW wrote:
JohnW, in article MPG.20d64a3e509a9bbb9897f8
@news.aaisp.net.uk, says...

You'll need more than 12v if they are sealed lead-acid,

http://preview.tinyurl.com/2359m9

It looks like the little one he
http://www.maplin.co.uk/images/Full/MM22Y_MM26D.jpg
Thanks.

So which way around do the jacks go? (Assuming I can still find them.)
I've got one of those Maplin's PW0140 Regulator Power Supply jobs the
kind that will work on 3, 6, 9 or 12 volts.

You need more than 12 volts DC to charge a 12 volt battery - a fully
charged 12 volt lead acid is officially 13.2 volts (2.2 per cell). The
rule of thumb figure is 13.8v to charge one. But like all chargers it's
the current that really matters.

You can make battery chargers - but like all such things can usually be
bought cheaper than the retail cost of the bits.

But if you or anyone else wants to have a go I have some pukka 5 amp 12
volt charging transformers designed for the job - all you'd need is a
rectifier and possibly a means of limiting the maximum current. I got a
crate of them off Ebay along with some other stuff and you can have one
for the cost of the postage.

--
*Pentium wise, pen and paper foolish *

Dave Plowman London SW
To e-mail, change noise into sound.

On 16 Jun, 13:17, "Dave Plowman (News)" wrote:
In article . com,
Weatherlawyer wrote:

On Jun 10, 7:45 pm, JohnW wrote:
JohnW, in article MPG.20d64a3e509a9bbb9897f8
@news.aaisp.net.uk, says...

You'll need more than 12v if they are sealed lead-acid,

http://preview.tinyurl.com/2359m9
It looks like the little one he
http://www.maplin.co.uk/images/Full/MM22Y_MM26D.jpg
Thanks.
So which way around do the jacks go? (Assuming I can still find them.)
I've got one of those Maplin's PW0140 Regulator Power Supply jobs the
kind that will work on 3, 6, 9 or 12 volts.

You need more than 12 volts DC to charge a 12 volt battery - a fully
charged 12 volt lead acid is officially 13.2 volts (2.2 per cell). The
rule of thumb figure is 13.8v to charge one. But like all chargers it's
the current that really matters.

You can make battery chargers - but like all such things can usually be
bought cheaper than the retail cost of the bits.

But if you or anyone else wants to have a go I have some pukka 5 amp 12
volt charging transformers designed for the job - all you'd need is a
rectifier and possibly a means of limiting the maximum current. I got a
crate of them off Ebay along with some other stuff and you can have one
for the cost of the postage.

SLAs have different charging requirement to non-gel cells. They should
not be charged with a car or bike charger. Charging v should be
significantly lower.


NT

In article .com,
wrote:
But if you or anyone else wants to have a go I have some pukka 5 amp
12 volt charging transformers designed for the job - all you'd need is
a rectifier and possibly a means of limiting the maximum current. I
got a crate of them off Ebay along with some other stuff and you can
have one for the cost of the postage.

SLAs have different charging requirement to non-gel cells. They should
not be charged with a car or bike charger. Charging v should be
significantly lower.

Assuming a reasonably large battery and a normal sort of domestic charger,
the internal impedance of the battery will prevent the voltage rising too
high to damage an SLA until it is near fully charged. Of course the
correct charger should be used, but other methods can be devised for a
cheap and cheerful solution as it would appear is needed.

--
*Avoid clichés like the plague. (They're old hat.) *

Dave Plowman London SW
To e-mail, change noise into sound.

On 16 Jun, 22:40, "Dave Plowman (News)" wrote:
In article .com,
wrote:

SLAs have different charging requirement to non-gel cells. They should
not be charged with a car or bike charger. Charging v should be
significantly lower.

Assuming a reasonably large battery and a normal sort of domestic charger,

from the pic it looks like a typical small SLA. A standard car battery
charger will charge it, but far too fast, so it wont last well. If
youre thinking more of a NiCd charger, that would be ok, if extremely
slow.

the internal impedance of the battery will prevent the voltage rising too
high to damage an SLA until it is near fully charged.

Are you sure thats what you meant? Internal R is typically a fraction
of an ohm, which will have more or less no effect on charging, and
especially so when full and charge i is at a minimum.


Of course the
correct charger should be used, but other methods can be devised for a
cheap and cheerful solution as it would appear is needed.

sure. the simplest of which is a wallwart.

Or how bout what they recommended in one of my old books, putting the
battery across the mains light switch contacts, so its in series with
the bulb. Would work on dc mains, until you operate the switch...
Would desulphate it too. Good idea?


NT

In article .com,
wrote:
On 16 Jun, 22:40, "Dave Plowman (News)" wrote:
In article .com,
wrote:

SLAs have different charging requirement to non-gel cells. They
should not be charged with a car or bike charger. Charging v should
be significantly lower.

Assuming a reasonably large battery and a normal sort of domestic
charger,

from the pic it looks like a typical small SLA. A standard car battery
charger will charge it, but far too fast, so it wont last well. If youre
thinking more of a NiCd charger, that would be ok, if extremely slow.

Ah - didn't look at the picture. I just assumed an emergency power source
meant a hefty battery.

the internal impedance of the battery will prevent the voltage rising
too high to damage an SLA until it is near fully charged.

Are you sure thats what you meant? Internal R is typically a fraction of
an ohm, which will have more or less no effect on charging, and
especially so when full and charge i is at a minimum.

It limits the current a charger can supply - you'd need a mighty meaty
unregulated type which could supply enough voltage and drive a battery
without using a series resistor.


Of course the correct charger should be used, but other methods can be
devised for a cheap and cheerful solution as it would appear is needed.

sure. the simplest of which is a wallwart.

Or how bout what they recommended in one of my old books, putting the
battery across the mains light switch contacts, so its in series with
the bulb. Would work on dc mains, until you operate the switch... Would
desulphate it too. Good idea?

;-) Any port in a storm.

--
*When cheese gets its picture taken, what does it say? *

Dave Plowman London SW
To e-mail, change noise into sound.