Build a 1S or 3.7 Volt Lithium Ion Battery Pack

Step 3: Charger

Get a smart charger.  This is the one used.  It is designed to be used used on packs at least 6 amp hours.  My pack is about 12 amp hours.  It should take 2 hours to charge.  

12 amp hour pack / 6 amp charger = 2 hour charge time

I cut the alligator clamps off the charger and wired them into the charge leads on the PCB.  

Comments

[dasimpson1981]

if these cells are of about 2200mah and you have all 20 cells connected i work out more then 12 amps

[CrudeBuster]

It seems he connected those in parallel, so it won't add voltage but current.

I use this kind of combination all the time, I've powered a small pair of cheap PC speakers to enable portable mode with cellphone batteries in a 4P + 4P combo, it recharges nicely with the old 9V power source they used.

The original safety circuit is still useful.

[dasimpson1981]

as I said these are all in parallel for 3.7 volt I count 20 cells if they are 2200mah each that is more then 12 ah

[CrudeBuster]

Oh, you're right, I misread your sentence, sorry.

And yeah, quite a big amperage on that pack, with a good DC-DC converter it could recharge cellphones in a cinch.

[dasimpson1981]

I have a pack like this I built my self that has 10 x 2.4ah cells making a 24ah battery but charge rate is very low at 500mah or so need to find a batter charge circuit