Tenergy universal charger - can I use it for 18650 ?

[dieselsmoke]

I have this Tenergy charger that I use with a 14.4v 4400maH pack, both purchased from all-battery.com.

http://www.all-battery.com/universalsmartchargerforli-ionpolymerbatterypack37v-148v1-4cells.aspx

This combination works well so far, but I recently ordered the infamous Trustfire 4151 charger along with some cells and a P7 flashlight from DX. I've done some reading here, and I don't really want to burn my house down so I'm not inclined to use that charger.

Is there any way to use my Tenergy charger with single or multiple 18650 cells ? Using an 18650 holder or cradle of some sort perhaps ?

I'm a noob when it comes to Li-Ion, so any guidance is appreciated.

 

[Benson]

FWIW, that Trustfire's not bad if you're running it off 110V (or presumably the 12V DC input) -- all the failures I know of result from running it on 220V, which it is rated for, but apparently can't actually handle. I'm currently using one on 110V to charge everything from 10440s up to 25500s, and it seems fine to me (although the 25500s seem to take all day...), no overcharging or anything.

Is there any way to use my Tenergy charger with single or multiple 18650 cells ? Using an 18650 holder or cradle of some sort perhaps ?

A holder would work fine, or grab a neodymium magnet in each alligator clip and stick them to the ends of the cell. That charger has 500mA CC (same as the Trustfire, in fact) so that would be about 0.25C on 18650s -- acceptable, but definitely not fast. Set the switch to 4.2V, and charge one cell at a time. You could connect several cells in parallel to charge, if they've been discharged to the same level, but that won't really go any faster than charging them one after the other, so there's no point.

That charger could be used to charge 2, 3, or 4 cells in series (which would be about as fast as charging one cell), using neodymium magnets between them, or multiple holders wired in series, but charging Li-ion cells in series is substantially more dangerous than charging them one at a time or in parallel, because the pack can become unbalanced and overcharge one cell before the others are fully charged. Only do this if you really know what you're doing, and then only if the cells are known to be discharged to the same level when you start (i.e., they were used together in a pack). If you try series charging mismatched or differently-charged cells, you may get lucky and only damage your expensive Li-ions -- or you may burn your house down, embed some battery-shrapnel in your flesh, or the like.

 

[dieselsmoke]

Thanks Benson, that magnet idea sounds simple and effective, and good to know the charger is capable.

Upon further reading I will be setting up a "safe" area for charging, maybe even in a metal shed outside that I have power run to. I don't have any 18650 cells now, and this flashlight will be my first device to use them, so I'll definitely stick to the safer route of one cell at a time if I use the Tenergy charger.

Lot's to learn about Li cells, glad I looked around here before treating as trivial them like the NiMH that I've had for years !