Charging 18650 yields hot cells

[Mr. Nobody]

I have a D2 and a D4 Nitecore chargers.
I just pulled 6 Sanyo cells from a laptop battery and stuck em all on the chargers.
Every battery but two that are slowly charging are EXTREMELY hot!
What is going on here? there slowly making there charge but unsafe due to them being un-holdable.

 

[WarRaven]

Stop everything.
Need more info but it sounds bad.

Was voltage checked during pull, as in pairs and then by single Cell? Paired cells can show dead where one is good but held down by a bad cell. Which is which?

The experts will have more info, but I'd stop, remove cells, move them outside for now if you haven't already.

 

[bdogps]

Batteries should not get hot when you charge them. None of my 18650 get hot when I charge them. Do you have a multimeter to check their voltage?

 

[Mr. Nobody]

the range from 3.78v through 4.01v. they were all on the charger all at once for 2 hours before I checked on them and noticed they were super hot to the touch.

 

[Mr. Nobody]

 

[Mr. Nobody]

 

[Mr. Nobody]

there date codes are as follows:
9gx2
8ew3
1ge1
9ew3
9ge1
3ew2

 

[bdogps]

Here is your answer you might be looking for:http://www.candlepowerforums.com/vb/showthread.php?259404-18650s-hot-while-charging

 

[Mr. Nobody]

UPDATE~

There Sanyo UR18650A
Is there a way to measure internal resistance to see which ones are truely bad and which ones are useable ?

 

[bdogps]

Measuring the battery's internal resistance is simple. All you need is a 4 ohm 5W power resistor or similar and a multimeter. Five common 1W 1 Ohm resistors in series would work. If you aren't measuring an 18650, choose a load resistance that will load the cell but not overload it. Capacity/3 should be ok.



1) First, measure the battery's voltage when charged. This is V1

2) Next, connect your multimeter leads to each side of the resistor and briefly connect the resistor across the battery. Note the voltage reading, this is V2.

3) Measure your resistor to get its precise resistance, this is R



4) The battery's internal resistance (Ri) is calculated with the formula:



Ri = (V1-V2)*R/V2



quoted from Dr. Lava from LPF

 

[SilverFox]

Hello Mr. Nobody,

If the cells get hot during normal charging they are truly bad.

Tom