Comments on: Battery charger circuit using LM317.

By: olusola seun

olusola seun — Fri, 30 Dec 2011 16:12:38 +0000

I’m student,i need your assistance by sending all the information materials i need for my project topic which Design and construction of an Automatic 12V car battery charger with a digital voltmeter display to me.your website is best website for all learners.

By: komal

komal — Sat, 15 Oct 2011 12:14:23 +0000

is it that we can use only acid lead batteries to charge? can we put like the mobile battery of 3.7 volts?

By: seetharaman

seetharaman — Wed, 27 Jul 2011 10:00:47 +0000

Hi Edgardo the aove circuit can be used with little modification. Raise R2 to 1.8K R5 to 470 ohms and raise the input voltage to 28to 30volt DC. Use a good heat sink for LM317.
Hi Anuj The above circuit can be used with modifications, kindly give the specification of your battery for the solution.

By: anuj

anuj — Mon, 25 Jul 2011 10:38:49 +0000

can i charge the 3v battery from the 9v battery.

By: Edgardo

Edgardo — Sun, 19 Jun 2011 08:39:16 +0000

Hi Seetharaman, Good day..
Can there be a circuit for a battery charger using LM317 by 24 volts lead acid batteries?
Thanks.
Edgardo

By: Seetharaman

Seetharaman — Thu, 02 Jun 2011 13:00:59 +0000

Hi NFERMITO the current is limited to 1.1amp (the ICs current limiting factor is 1.5amps even without external limiting circuit) hence the wattage dissipation is just 0.35watts with 1.1amp, hence 1/2 watt is sufficient at the most you can use 1watt resistance.

By: nfermito

nfermito — Tue, 31 May 2011 17:13:06 +0000

R1 is 5W according to another internet site. Take care of it.

By: Amaechi Uche

Amaechi Uche — Tue, 22 Mar 2011 03:01:24 +0000

Hi, am a student who needs help on is project to Design a constant power battery charger with inherent soft-switching.

By: Seetharaman

Seetharaman — Sat, 04 Dec 2010 12:16:01 +0000

Hi Lao without battery set the output voltage at 13.8volt with pot for 12 volt battery for normal charge. set the voltage at 14.5 volt for boost charge. as the terminal voltage trying to reach the set voltage the charging current will fall down automatically. this setting will suit only 12volt lead acid batteries.

By: lau

lau — Fri, 03 Dec 2010 13:09:14 +0000

Hi, how can i set the set current? how can i control the current during charging and fully charge?