What is in behind this lie? can any one help me with this? I charged CGR18650E and result went 4800amh

[lenyee]

I charged one of recycled lithium 18650 battery when testing the capacity it read 4800mah in litokala lii500 the batterry model is CGR18650E

 

[OffGridInTheCity]

There are several possibilities from weird equipment to severe self-discharging (causing more charging). As you say, it's not possible for 18650 to have this much capacity. Would start by trying some known good cells to confirm equipment is working correctly. If equipment is good, then I'd be suspicious of these cells.

 

[Wolf]

There are no lies in the Li-Ion world only facts.
Background:
The CGR18650E is an early version of the INR chemistry that Panasonic developed to create a "safer" cell.
It also had the advantage of high charge/discharge rate for its day (early 90's) 0.7C, 1750 mA max charge and 1.0C, 2450 mA max discharge,
≤35mΩ IR and a 500 cycle count.

So fact gathering time,
What is the date code on the cell? It will be a 4 digit number on the bottom of the cell and look like this>>>>>
What is the 1kHz IR reading of this cell?
What was the original voltage measured when the cell was first touched?
At what mA are you charging this cell at? 300mA/500mA/700mA and 1000mA?

Now some observations:
If charging a 2550mAh cell at 1000mA it should only take ≈2.5hrs to charge from dead empty 2.5V. ( Some datasheets say 3.0V cut-off some say 2.5V.)
What I see is the cell has been charging for 5 hrs putting in 4839mAh so yea I would say you are probably charging at 1000mA.

The temperature of 43° C is quite warm if not almost hot to the touch depending on your interpretation,
and it clearly lets you know that at least 2289 mAh's from the 4839 mAh that has been "charged" has been converted to around 9W of heat.
Great in the winter

In conclusion:
You have what we call a Vampire Cell.
Wolf

 

[Korishan]

anything that hot, discharge it to 0V and toss it. Don't even gamble on trying to resuscitate it. It's not worth the risk.

Discharging to 0V is pretty simple. Take any kind of resistive load, a small incandescent (aka filament) light and tape it to the ends to make it discharge. You could use leds, but they take longer. Could also use some heating wire from a toaster or hair dryer.
When the cell is practically discharge, or completely, take a strip of bare wire and solder/tape it to the ends creating a dead short (ONLY do this after it's been fully discharged!) This is to ensure no bounce back and keeps it at completely 0V with absolutely no chance of a spark.
Then toss it into recycling (if yours accepts lithium) or in the rubbish bin.

 

[paddy72]

I would generally do the capacity measurment during discharge, not when charging! There are so many side effects when charging (bad connections, losses in charging, IR of the cell etc.) that the value is not reliable at all. Anyway, as Wolf said, there a high chance the cell is bad, very bad. If you try at all, you should charge it at low rates (max. 500 mA) and observe cell temperature continously - than do the discharge and you have the real capacity.

 

[italianuser]

To do a proper capacity check with Liitokala 500 you must choose NOR test (not FastTest), which will do a complete C/D/C -> charge, discharge, charge cycle. When completing the discharging cycle your will know the measured capacity.

 

[OLEK94]

those Litokala gadgets gives capcacitry results that are optimistic at best between 500 and 900mA falsely appreciated)

I want to make the testing "official' from the datasheet ; they explain how to Charge then discharge in the following hour also with given data

for instance charge with 4.3V for 3hours at 1400mA (half the capacity of the battery) - for these I need to use my power source Riden 180 that can be regulated for those 2 values, and if I use the "charging" mode it will provide a constant current until no more current is accepted then switch to "constant voltage" and you can see the power (amps) lowering dow, to zero.

then discharge , when the battery have cooled enough it is done with a small amp i.e 560 mA until the battery is 2.75 V or 3.0V (again depends of the,datasheet)

look for "standard charge and discharge parameters" here are gtood explanations in French but English subtitles are good

View: https://www.youtube.com/watch?v=j4mdaokeM9M&t=640s



Regards

 

[OLEK94]

anything that hot, discharge it to 0V and toss it. Don't even gamble on trying to resuscitate it. It's not worth the risk.

Discharging to 0V is pretty simple. Take any kind of resistive load, a small incandescent (aka filament) light and tape it to the ends to make it discharge. You could use leds, but they take longer. Could also use some heating wire from a toaster or hair dryer.
When the cell is practically discharge, or completely, take a strip of bare wire and solder/tape it to the ends creating a dead short (ONLY do this after it's been fully discharged!) This is to ensure no bounce back and keeps it at completely 0V with absolutely no chance of a spark.
Then toss it into recycling (if yours accepts lithium) or in the rubbish bin.

please why discharging to Zero ? no risk of fire if the battery is toss ? I have seen dead batteries 18650 assembly, with BMS taking fire by themself (thermal runaway) Regards

 

[Korishan]

please why discharging to Zero ? no risk of fire if the battery is toss ? I have seen dead batteries 18650 assembly, with BMS taking fire by themself (thermal runaway) Regards

0-volts means there is no possible way for the battery to have enough of a charge to create a thermal condition and ignite.

Not sure what you mean by the rest of your post

for instance charge with 4.3V

Do not do this with regular Li-Ion cells that are rated for High Voltage (HV). Going over 4.2V will rapidly destroy normal Li-Ion cells. Even the HV ones live a short life cycle because of this, though they are designed to handle the higher voltage, altho they suffer from the longevity as the other Li-Ion cells.

3hours at 1400mA

Charging at this high rate of current is also not recommended unless again, the cells are designed to handle such high current. The ones that the OP shows in their posting are NOT High Voltage or High Current cells. Charging at this high current rate could create possible fire risk.

They were already charging at 1000mA when the cell was reading super hot to begin with. Add more current would push them over the edge quickly!!

Doesn't matter if the tester here was reading high on the capacity or not. The fact is that the cell(s) were getting way too hot with the given test parameters that was way out of spec. Increasing voltage/current would not "decrease" risk of fire/explosion, and would actually drastically increase it.
We do not advocate carelessness on this forum when it comes to possible loss of property or life. And this could be easily been the case if following the example to boost voltage and/or current.

 

[paulie]

lol, I use the good old bench vice to discharge useless batteries which are 3 volts or less down to 0volt. . Do not try this with a fully charged 18650.
I forgot once and had a bit of a display. Won't do that again.

 

[OLEK94]

0-volts means there is no possible way for the battery to have enough of a charge to create a thermal condition and ignite.

Not sure what you mean by the rest of your post

Thank you for your words of caution and the rest The battery I have seen self ignite whils showing zero volt output was certainly just with BMS blocking the output. (so my appreciation that thy where dead empty was not accurate probably)

The 43 V was in a datasheet from Samsung 1860 1858088A protocol (2800mA/h but I do not know if that are high capacity cells , they shouild be no less than 2700mA) the directions are : 1400mA 43V fror 3hours AT 25°c (they name that "standard charge" ) I understand this is brutal and may create thermic problem if the cells are not new or mint condition... BTW I tested a 7.5A 36V battery with 3750Ma OR 265w AND while a balancing module was welded and balancing along the dischage. In 30 mn I did go down to 30V then the DM24 stopped . I obtained a 7540mA reading on the DL24 screen and software. Once stopped I find voltage rising soon to 36 V are the capacities from the balancer allowing that (1A balancer from 100Balance-Daly) ? Best regards -
a resume at 25min : https://photos.fife.usercontent.goo...U-87_vD7_y8ExJQw=w383-h829-s-no-gm?authuser=0

That i_s a somewhat old scooter battery (2.5years) that did not hold long because the balance was way off. I was explained the in absence of balancing module the balancing if any happens only at the very end of charging, does it mean after the charger led goes to green (still 42.45 V in the circuitry seem to me)

 

[OLEK94]

I just was noticed that the Atorch electronic load make CDC (loop) to evaluate capacity . only the model DL24EW (with an added power supply but seem to me it does not go higher than 28V)

I thought that mean that charging can be survey , in the end no it is written in red on their official aliexpress shop "No charging" (may be only because the voltage is 28 V max , I am not sure

Edit : I asked and was said charging survey was able but using your own charger or power supply. The original power supply of the DL24 EW does not allow separate charging I asked if the power supply was supposed to make CC CV or if one sending only CV could be managed by the DL24 EW

I will keep you posted
Regards

 

[OLEK94]

Hello, I tested a little battery for a scooter/trotinette (?)10S2p 7.5A. Using the Atorch DL24M, I inserted the temp probe into the battery, and draw 4 A. At 36.9V, after 22 min the DL24 stopped with a 35°c temperature alarm .

does that temperature mean the battery is tired, weak or bad quality ? it turns out that I obtained 3600 mA at 25 min.

what do you think ? I think that for a battery capacity check it is better to stop at nominal value 36V, even at 36V the scooter do not work really well .
testing down to 2.895 or 3V is following the battery maker instructions, but for one cell only. I do not understand what information it would give me, even if more Amps are drawn. What is your point ?

and for the temperature ? I have another battery with bigger Samsung 21700 M50T cells and no heat is showing up while I draw 7A

THank you

 

[italianuser]

At 36.9V, after 22 min the DL24 stopped with a 35°c temperature alarm

You're drawing 4A from a 7.5Ah battery which is a good amount of current which heats up cells. If you tried drawing out 1A it would heat up less.
35°C doesn't seen high to me because it's quite a hight load. But I could be wrong because I check the heat (during CDC cycles) by touching the cells.

Your test was blocked by the temperature sensor. Maybe the cells are really the capacity you measured. The Samsung INR18650-30Q after 250 cycles should have a 60% capacity left. That's what happens with power cells because they're heavy duty cells.