Charging a Lead Acid Battery

22 Jul 2007
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United Kingdom
I have a ReChargeable Torch with a 6vdc sealed lead acid battery & 12v charger/adapter/smps.

The thing has stopped taking a charge.
The charger/? seems to be working o.k.
The battery is new and will hold a charge when given one.

To me (?!) it looks like something in/on the regulator board in the torch handle has gone.

At the moment I have the battery out & charging it on my sons car batt charger (6V).

I don't mind doing this once in a while, but was wondering if I can cut out the regulator board and feed the battery direct from something like a car batt charger.

1/ Am I right in assuming that I can just take out the board + make an adapter lead to connect charger to input on torch ?
2/ Can I just use a 6vdc charger/adapter/smps (with appropriate aH) and also bypass the board ?

Of course, this isn't life threatening and I know that some of you will think (and say) "it's a cheap piece of tat - throw it away". Obviously you arn't the guys that I'm trying to reach.
I'm now disabled and trying to keep my hands and brain ticking over,,,, so I do like to try fixing things. If all else fails, I will replace it - but in the meantime,,,,,

any help or advice will be appreciated.

thanks for reading
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If you have a 6v battery charger, then yes, you can remove the board and just connect directly to the charger.
You can't connect a power supply directly to the battery, since there will be no current regulation and the results will probably be the power supply overheating or the battery being damaged.

However charging circuits are usually simple, and if it has just stopped working, the fault should be easy to fix. A likely failure is where the socket is soldered onto the circuit board, or the socket itself.
The charger should be compatible with the battery and its prefered charging method to get the best life ( most dis-charge ~~ re-charge cycles ).

Some charger and battery combinations are constant current charge. Some are constant voltage and some are intelligent with vaying current as the battery reaches full charge.

That said providing the charger does not force too much current into the battery it will be safe to charge from a different 6 volt charger but for the first few times keep a watch on the battery for over heating or gas coming out of the vent.

CAUTION if there is too much current and the gassing occurs then beware as the gas is extremely inflammable being an explosive mixture of hydrogen and oxygen. NO flames or sparks anywhere near until the gas has dispersed. Turn the charger OFF before disconnecting the leads.

A car battery in a shed outgassed enough that the explosion cracked the windows. The explosion burnt back into the battery and the explosion inside the battery cells split three of them open.
Thanks for that. The board looks pretty simple, but I can't see anything burnt or obviously wrong - except the LED doesn't light up when on charge either. I don't s'pose the power goes 'through' the LED ?
I have a cheap 'multi-tester' but I'm not clever enough to locate faults in components.
I could replace the LED if I know the size of it.
The input socket works fine. Switches power line when inserting charger plug etc.

Thanks for the technical heads-up.
If i'm reading it right, the trickle charger that I borrowed from my Son, puts out 3amps.
I tried it for a couple of hours and it all seems well. The battery got a little warm, as I would expect.

I don't have a charger now. My good 'old faithful' packed up after 40 years - damn things don't seem to last eh :rolleyes: ?!?!

For the time being, the torch is back together,,,, till the next time.

thanks for taking the time to help.
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