My newly salvaged sanyo 18650 getting really hot when charged

[Ammitz]

Hi all

first of all im pretty new in this battery thing and wanna say hello.

i purchased my first NCR18650B cells a few month ago. and with that i purchased a Liitokala Lii-260 Charger

yesterday i salvaged my first laptop battery a got 9 very nice Sanyo L45A cells from it.

Used a multimeter to check if the cells are dead or not . all 9 measured around 3.6V - 3.7V.

i popped 2 im my charger and set the charger to 500mA in the discharge mode when i got home, i checked regularly on them, to make sure everything is fine.


A hour later i noticed he charger measured 4.2V. but the charger still pumped voltage in to the battery, witch resulted in a very-very hot battery.

i was determed to figur out what vent wrong, and i connected my Fluke multimeter on it...

now i measured 4.236 V or 4236 mV and it seamed to be stalled on that voltage.

somehow my charger didden stop the charging cycle and continues to charge.

Next i did a discharge test with my NCR18650B from Panasonic,with my fluke connected and i noticed that the charger only start discharging when the voltage reached 4.257mV with is a overcharge. but my Panasonic cell did dent turn hot.

now im a bit worried that my charger is faulty or is it my newly salvaged cells that are bad ? im a bit confused .

 

[SilverFox]

Hello Ammitz,

Welcome to CPF.

LiIon cells utilize a Constant Current/Constant Voltage charging algorithm. That means that since you selected 500 mA for charging the charger should charge at 500 mA until the voltage reaches 4.2 volts. There is some leeway with this voltage usually listed as + or - 0.05 volts. That means that overcharge is when the voltage exceeds 4.25 volts.

When the maximum voltage is reached, the voltage holds steady and the current drops off. At some point the current drops below a set point and the charge shuts off.

So far it sounds like everything is going according to plan. The maximum voltage is a little high but still within range. The issue is that the cells shouldn't get hot.

Sometimes they will warm up a little but they shouldn't get hot.

Without more information I would suggest you purchase a new cell of high quality and see if it gets hot too. If it doesn't, that suggests that your recovered cells have issues and you probably shouldn't use them.

Tom

 

[CelticCross74]

unless somebody gives a laptop battery pack to me that is almost new I would never use salvaged battery pack cells. Just much much easier and safer to cough up the dough for quality singles.

 

[Ammitz]

being afraid of burning my house down with a falty charger or battery, ive deside to buy a Skyrc MC 3000 charger. better be safe than sorry.

 

[Gauss163]

Most likely your salvaged cells have very high IR (Internal resistance). The higher the IR the higher the heat they generate while charging. This is not a problem with the charger but, rather, with the cells. Those salvaged cells are most likely long past end-of-life.

 

[Ammitz]

when i insert the cell in my charger it does a resistance test shoving 0061mR.. dont know it thats are valid data..

Most likely your salvaged cells have very high IR (Internal resistance). The higher the IR the higher the heat they generate while charging. This is not a problem with the charger but, rather, with the cells. Those salvaged cells are most likely long past end-of-life.

 

[bella-headlight]

For the small cost why not just buy quality cells & have peace of mind ?
I had a lot of lap top pulls (well about 16) & TBH their performance is nothing like new high capacity/drain quality new cells, the best were only about 2200 mah.
I just ditched (recycled) a dozen of them.
I have recently bought 8 Panasonic 3400 mah 18650 NCRB"s protected for under $4 a cell delivered & 8 of the same cell unprotected for a little less.
For the price I can"t see the point in laptop pulls anymore.

 

[Ammitz]

I dont know where you are buying from. but cheapest online shop her in Denmark with day to day delevery got the panasonic NCR18650B for $12 and $10.70. a pice if you buy more than 5 cells.

For the small cost why not just buy quality cells & have peace of mind ?
I had a lot of lap top pulls (well about 16) & TBH their performance is nothing like new high capacity/drain quality new cells, the best were only about 2200 mah.
I just ditched (recycled) a dozen of them.
I have recently bought 8 Panasonic 3400 mah 18650 NCRB"s protected for under $4 a cell delivered & 8 of the same cell unprotected for a little less.
For the price I can"t see the point in laptop pulls anymore.

 

[bella-headlight]

We had a group buy over on BLF from Gearbest on the protected cells.
Here you go http://www.gearbest.com/batteries/pp_189823.html 4 unprotected Panasonic 3400 mah NCRB"s for $13.48 delivered or £3.37 each cell.
Protected version http://www.gearbest.com/batteries/pp_189833.html?wid=1 for $17.94 for 4 or $4.49 each.
Lots of people have bought both versions & they have checked out as genuine.
Just be aware that the protected cells are very long at 70.30mm.
Your laptop pulls will be unprotected so the unprotected version should do you & will have much more capacity.
Oh & here in the UK they also charge $12 a cell so basically I got 3 free on each 4 pack.

 

[Gauss163]

when i insert the cell in my charger it does a resistance test shoving 0061mR.. dont know it thats are valid data..

That's very close to the value HKJ reported in his review. However, as he mentioned there, it is not clear what those numbers are supposed to mean, since they don't seem to correspond to values in Ohms - e.g. he added 100 ohms but the test reported only a 50 ohms increase (if I correctly interpret the terse remarks in the review). As such, it is not clear that the charger would correctly detect and report cells with high IR. Perhaps HKJ will chime in with further thoughts (or others who have access to an Lii-260, which I do not).