• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

someone can help me modify this circuit ??

Status
Not open for further replies.

MikeMl

Well-Known Member
Most Helpful Member
Does it really never finish the charge, i.e. revert to the lower voltage, or does it just never turn on the LED?
 

Chippie

Member
There's nothing wrong with the circuit..it functions as designed by Scott...I've built several for charging lipo batteries and its a characteristic that the battery never appears full because the charging regime reverts to constant voltage with an end point of 4.22v/cell....so a small current will flow...but not enough for the led to remain lit...

You could add some sort of detection circuitry around the current sensing resistor to turn off charging but is it worth it...I think not..just disconnect when the led goes out
 

ericgibbs

Well-Known Member
Most Helpful Member
The original circuit published in the LM317, 1994 datasheet works OK.

Just add an LED indicator.
 

Attachments

lazyhut

New Member
thanks for reply
above the circuit will never finish the charge even less current it draws..

now my problem is how to modify it auto turn off battery charger when has been fully charged.

but i have no point to modify it..
 

ericgibbs

Well-Known Member
Most Helpful Member
thanks for reply
above the circuit will never finish the charge even less current it draws..

now my problem is how to modify it auto turn off battery charger when has been fully charged.

but i have no point to modify it..
I would suggest you follow 'Chippies' advice, when the led goes out, disconnect the battery.:)
 
Last edited:
Status
Not open for further replies.

EE World Online Articles

Loading
Top