6v LeadAcid Battery Charging ?

[FUTURETECH]

Hi all ....

I'm busy building a 6v LeadAcid battery charger for a 6v 12Ahr battery. I'm in the electronic security trade and do electronics as a hobby.

In alarmsystem/applications the system has a build-in back-up battery charging function to keep the 12v 7Ahr battery charged.
One also get a small stand-alone 12v DC 1 Amp (LM317T)charger module with which one can charge these batteries.

My question regarding this - if this 12v 7Ahr battery has been run-down quite a bit, say to 8.5v, what amount of amps will it drawn from such a charger unit( the stand-alone module ), as this regulator could only supply a max of 1.5 amp ? F Y I - these charging modules are useally " feed " from a 16v AC 40va transformer.


Furtheron, would it then be possible to use the same regulator for charging the 6v 12Ahr battery ? I'm using a 4K7 trimpot to adjust the charging voltage to 10.5v as the batterie's constant charging voltage is 7.45 v - keeping in mind the 3v voltagedrop accross the regulator.
I'm using a 12v 1 Amp transformer to " feed " my charger module.

Iwould appreciate any info regarding this setup and how to go about solving / building it .

Regards

 

[MikeMl]

Go to National's web site, and read the **broken link removed**. It has a battery charger shown in the "Suggested Circuits" section.

Also find **broken link removed**. It shows you how to build current-limiting in to avoid cooking the regulator when it is used for battery charging.

 

[FUTURETECH]

MikeMl...

Thanks for the info ! I'v seen this 6v chargercircuit also on the LM338 datasheet, the bigger brother of the LM317 .

Regards