Cheap Li-ion charger.

[Kevin Tan]

Went to Sabahoceanic and got 2x17670 but cannot find the charger for it. So went back home, dug out the old Nokia 3110 li-ion batt pack to get the protection circuit. Got a cheap dual desktop charger for the same fone. Dismanteled the desktop charger and soldered the 3 wired contact to the protection circuit. Got a piece of 2x4 wood and used a nail as the +ve and a battery serial connector plate from a cheap rc car, bent the plate and anchored the +ve with 2 small screws and used the spring as +ve. solder 2 wire to protection circuit batt tabs ( the tabs are soldered to circuit and welded to batt) connec the wires from the circuit to contacts, plug in supply and success!!!

It took 6.5hrs to charge a piece of 17670 to 4.25V at which point the desktop charger indicator changed gradually from red to green. My supply is rates as 4.5V 300ma.

 

[koala]

Kevin,
I did try your trick to remove the existing prismatic battery of the nokia and actually use the mobile itself to charge the Li-Ions but they seems to take forever.

Another charger you want to try out if you like to DIY build your own..

http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Board=UBB6&Number=320252&Forum=UBB6&Words=&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=allposts&Main=320252&Search=true#Post320252

CM is also playing with one from Linear if I am not wrong. His requires less components. If I memory serve me correct...

 

[Kevin Tan]

Nukiez, I have a few models of the Nokia wall wart. Some of them especially the lightweight one put out a lot more mAh and do charge the fones faster. Since I only use 1x17670 at a time I don't mind the long charge time. Plus the batt never even warms up to touch.

 

[koala]

Yes Li-Ion should stay cool when charging.

I am doing a total discharge(<0.1v) on an old laptop 18650 1300mAh and see what will happen. It took the first charging stage(charge at 1/10C) without a problem. Now it's 3.0v at second stage, 1C charging. I wonder if it will hold more or less charge after this.

This is actually a cell that I revived, initially it refuse to accept any charge but after a few charge and discharge cycle it's working fine. Hopefully it will survive the crazy test.

Vince.