to make a lead acid battery charger.

sashibhusan sahoo's picture

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to make a lead acid battery charger.
November 4, 2016 - 3:43am

sir, i have a lead acid rechargable battery with specification 12v 7ah. can i use a 5a 0-15v stepdown transformer to recharge such battery? is it a efficient idea? if not then kindly give some better idea about transformer for such application.thankyou.

Aswinth Raj's picture

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Joined: Aug 16, 2016

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Hi Sahoo,
November 4, 2016 - 10:47am

Hi Sahoo,

You should not charge a 12V 7Ah battery with 5A current. The charging current of a Battery depends on its Ah eating. To be on safe side 1/10 of the Ah rating is used as charging current.

In your case (7*(1/10)) = 0.7A, would be your apt charging current, although to speed up the process you can use upto 1A. But a high current of 5A would surely kill the battery. 

A 12 Lead Acid battery should have 13.5 Volts when it is fully charged and should not be allowed to discharge less than 10.5 Volts. A charging voltage of 15V would not do any harm to the battery but 14V is recommended. 

The most easy way to charge your battery is to use a 15V 2Amps step down transformer to main source and convert it to DC, then use normal LM317 Regulator ICs to Regulate your required voltage and limit the output current. 

Hope this helps, if you get stuck somewhere let us know, we will be glad to help you out.

 

HAPPY LEARNING!!

sashibhusan sahoo's picture

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Accroding to you, If I
November 4, 2016 - 3:33pm

Accroding to you, If I connect a 2a 15 0v or 15 0 15 transformer to recharge 12v,7ah battery, then tell me is it a efficient idea. And how many hour needed to achieve battery top up charge.

sashibhusan sahoo's picture

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Am i fed such 12v 7ah battery
November 5, 2016 - 12:55am

Am i fed such 12v 7ah battery in the 100wt inverter circuit?

Aswinth Raj's picture

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I you connect 14V 1A charger
November 6, 2016 - 8:40pm

I you connect 14V 1A charger to 12V 7Ah battery it would roughly take around 8 hours. 

Yes it is efficient.