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Melvin001
07-15-2008, 05:00 PM
I have bought a 12 V lead acid battery, current rating 1.2 Ah !!!

Now, the real problem is how to charge it, i have found plenty of circuits to charge them,, some uses L200,, other one with LM350. All of them are too complex!!!

Can i use a simple transformer with rectifier and a regulator (7812) and connect respective terminals???

If yes, what should be the rating of of transformer and the diodes??

Thanking you all, in anticipation :D

maddy_nish
07-16-2008, 01:06 PM
Hi Melvin!!


U can simply use a diode(in4007) along with a 12v 500 ma transformer.
The diode can stand up to 2A of current while the charging current generally should not exceed 350 ma. But a transformer with a half wave rectifier would do your purpose.

MohitM
07-16-2008, 02:38 PM
I doubt it very much that you can charge it with a 7812. Lead acid needs about 14V to charge.

There is huge info all over the net on this topic.

a7400
07-16-2008, 06:37 PM
www.batteryuniversity.com

asimov_18
07-16-2008, 09:25 PM
hi there is a novel way of using 7812 to generate 14.1V. use a 7812 .as u know pin 1 = in put
pin2= gnd
pin3= output.

connect the output of the of the rectfied and filtered dc power supply to the pin1 of of the IC. Now instead ofdirectly grounding the pin2 of the IC connect it to 3 Diodes connected in serries with the pin2 connected to anode of the diode and the last diodes cathode grounded. with this arrangement the pin 3 of the Ic should give about 14.1V if the volatge drop across the diode is assumed to be 0.7V



simple and beautiful isnt it..........



asimov

Melvin001
07-17-2008, 08:12 PM
Thanks All!!

@ maddy_nish

Whats wrong with full wave rectifier, can i use it, instead of half wave rectifier??

@Mohit_M

I think i should you 7815, if this is the case.

@a7400

Thanks for the link, nice find.

@Asimov

For the first time i have came to know about this idea,, i`ll surely try this, may be i can use this at many other places. :D


My last question is, how should i decide the charging time, and when i`ll know that my battery is being discharged?

i think this can be recognized by measuring voltages!! am i right??

Any other suggestions to increase the life of batteries??

Thanks again!!

qwerty
07-19-2008, 12:35 AM
I have bought a 12 V lead acid battery, current rating 1.2 Ah !!!

Now, the real problem is how to charge it, i have found plenty of circuits to charge them,, some uses L200,, other one with LM350. All of them are too complex!!!

Can i use a simple transformer with rectifier and a regulator (7812) and connect respective terminals???

If yes, what should be the rating of of transformer and the diodes??

Thanking you all, in anticipation :D

i think there is a simple way of charging your battery
do you have a ups in your home?
if you have just replace the ups battery with your battery and you can simply charge :) :)

maddy_nish
07-19-2008, 12:45 PM
Nothing wrong with full wave rectifier.. Just trying to simplify your job..