Nexxtech Charger AA/AAA charger for 18650?

[markz]

The Source/RadioShack - House brand is Nexxtech

Model # 2300455
Universal Ni-Cd/Ni-MH charger and tester
Class 2 battery charger
3va out max

C/D's are 2x 2.8V 500ma
AA is 2x 2.8V 260mA
AAA is 2x 2.8 128mA



Can I use the AAA to charge single 18650 @ 128mA at 2.80V, the 18650 are very low voltage, 0.50V to 1.00V.
The only other charger I have is for a cell phone and is 5V 1A and some get hot.

 

[jonyjoe303]

when a battery is that low it usually won't even take a charge. But even if it charges, it will stop as soon as battery reaches 1.2 volts (the max for a nicad). The 2.8 volt they mention is if you charge 2 batteries 2x 1.2 volts (1.4 volts full charge per battery) All nicads max out at 1.2 volts.

The cell phone charger will work better since it will stop at 4.2 volts same as a 18650, but again it might not be able to get the battery to even charge at that low voltage. And 1 amp might be too high for recovery of cells.

For cells that low I use the foxnovo 4s, its the only charger I use that can actually get a 1 volt 18650 to charge. You have to insert the battery in and out of the slot several times until it "jumpstarts" then it starts charging.

 

[amberwolf]

the 18650 are very low voltage, 0.50V to 1.00V.

Those are unsafe to recharge, are physically damaged inside, and are a fire hazard.

If you recharge them, you risk a fire during the recharge or discharge or just sitting there, either then or at any time afterward.

Your choice, but I'd get rid of them.

 

[Hillhater]

FYI.... there was a thread recently reporting on 18650 testing ( Tesla cells ?) where the author deliberately took cells down to 0.0v by shorting for several hours. Those cells were then recharged and performed normally in subsequent tests !
EDIT...
Here it is..member Okashira, March 18th 2015.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=67721&hilit=Tesla+cell+testing
But yes, not many cells will be that forgiving !

 

[amberwolf]

Others have not always had good luck doing that; some cells have self-heated (in a pack where heat is contained that might've ended up in htermal runaway). Some just stay dead, some have other poor results.

So...I still wouldn't do it, just becuase nothing bad happened yet to the cells that guy did it with.

 

[Punx0r]

There's a big difference between a cell that's temporarily been taken down to low voltage for a few hours and one that's self-discharged down to that level over a long period.

 

[Hillhater]

Well its all just speculation since we dont know what these cells are, their chemistry, history, etc etc
Another FYI..

....Quallion’s patented Zero-Volt technology enables a lithium
ion battery to be completely discharged to an inert state, stored
in this condition for an extended period, and then recharged
without any permanent damage to the battery or reduction in capacity
or performance. ......

 

[john61ct]

All depends on the chemistry used.

LTO is supposed to be OK with such treatment.

I would not trust normal LI chemistries, especially that used by Tesla or similar.

 

[markz]

OK here is the low down on my situation

Samsung 18650 25R from nkon
bought brand new, tab welded
the pack shorted
let sit for 4 months
some are at 0.50V
some are at 1.50V

will throw 'em out, not worth the risk!

 

[john61ct]

yes good idea

fully short in seawater first