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Car Battery Charger

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New Member
Firstly, i want to salute all members of this forum
i am trying to design Car Battery Charger , and i want some information
how much ampere to charge for fast charge and for slow charge , if you have circuit diagram .
i need you help pleaseeeeeeeee.


Active Member
Look back thru posts for a question about charging "calcium" batteries. I responded there a month or so ago with the url (I forgot what it is) for a good technical description of how to charge a lead-acid battery for best life and performance. I recall that the best charge rate when the battery was discharged was something like 2 amps - but best to read thru it so you can decide what's best for your application.


A commercial car battery charger I used to have had a low setting of 2 amps and a high setting of 10 amps.

If you charge your battery at no higher than 13.8 volts it'll last longer.


New Member
i need a charged circiut diagram supply 12 volt (battery car) and current of 15 A As batteries have 70 ,50 or 90 A
do you have it
thank you
i have a circiut diagram for 3 A only send in the attachment



Dear Ahmed,

You may get a charger ckt from National Semiconductor Data sheet for LM350. I build this ckt and now it is up & running. Also you get a battery overflow indicator therein. If you go through that ckt, you will note that there is no mechanism to prevent BATT being discharging into the IC when ther is a mains power failer. So what I did was, I put a doide (IN5408) to stop this. However, with this alternative, there is a little voltage drop but negligible.
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