How do I modify my Li-ion charging circuit with LM339N?

I recently found a dead laptop battery and disassembled it, found 6 batteries of CGR18650. So when I checked with them my multimeter, they had quite bit of voltage. So I decided to charge them, since I didn't want to spend money for a charger, I decided to make one. I made it and now I'm able to charge my batteries. I'm watching charging current using my multimeter. So I found LM339N voltage comparator IC inside a broken power-supply and the IC is working.

Here's the sketch of charging circuit,


So how do I modify my charging circuit with LM339N, I'm not an expert in electronics. I just have some basic knowledge about batteries that I read from an electronic blog named Kynix Semiconductor Electronic Blog . Since I don't want my multimeter to be connected with the battery to measure current, I want to make some led bulbs glow when the charging is completed.

how do I modify my charging circuit with LM339N

Click to expand...

To achieve what exactly?

LM339 = quad comparator.
The schematic at the moment is a voltage limited constant current source. I'm not sure why you would want to add a comparator to it.

Brian.

Hi,

You would need to find the drop-off point for charging, when the battery is charged, interpret it as a useful voltage with no side-effects/unwanted comparator trigger points and then get the comparator to turn on your LEDs. Not sure how you'd do that, though. If you are able to detect the voltage rise in the battery, then it would be as easy as setting the comparator trip point at that voltage. I add that I think Li-Ion are a bit more complicated than just measuring a voltage, it would be an idea to read somewhat more on the subject.