Pre-made li-ion packs and generic li-ion cell charger?

[jankj]

Is it advisable, possible, smart or plain dumb to hook up a multi-cell, parallel coupled li-ion battery pack with a generic li-ion single cell charger?

Such as the Battery junction 3*2200mAh, 3.7 v battery pack http://www.batteryjunction.com/tenergy-37-6600-pcb.html
and the popular Ultrafire WF-139 charger? (Just using a crocodile connector cable or make a plug to hook the battery pack to the charging terminals).

I am assuming a whole bunch of stuff with this setup, namely:
- The cells of pre-made battery packs are pretty well balanced
- Charging li-ion cells in parallel is not harmful, at least if the cells are at somewhat similar charge status.
- The Ultrafire charger won't blow up or anything.
and probably some stuff I've forgotton.

Any thoughts and comments?

 

[45/70]

OK, jankj, I'll give a shot at this.

I am assuming a whole bunch of stuff with this setup, namely:
- The cells of pre-made battery packs are pretty well balanced

It's highly unlikely that these cells are actually matched. It takes time and trouble to sort through cells, testing them several times etc. to match them up. Usually truly matched packs are relatively expensive because of this. When charging Li-Ion cells in parallel however, it doesn't make a whole lot of difference.

- Charging li-ion cells in parallel is not harmful, at least if the cells are at somewhat similar charge status.

This is true. Li-Ion cells should be within 0.5 Volts of each other when parallel charging. This is pretty easy to do.

- The Ultrafire charger won't blow up or anything.

You're on your own here. A lot of people use this charger, and are pleased with it. The chargers seem to be "hit and miss" as to their QC. These chargers also use an improper algorithm, for charging Li-Ion cells. The worst aspects about them are they trickle charge cells after the LED turns green. This is bad for the cells and can be dangerous, if the cells are not removed from the charger when the LED turns green. Also, some units charge to a much higher voltage than recommended, again, bad for the cells and can be dangerous.

Your plan will work. Personally, I'd look into a better charger though.

Dave