Wolf-Eyes 18500 with Ultrafire WF-139 charger

[Flash007]

Hi,

When I charge the W-E protected 18500 3,7V 1400mAH Li-ion cells with my Ultrafire charger WF-139, the voltage at the end of charge is 4.23 - 4.24V.
Is it a very high value ?
Do you think it will shorten considerably the amount of charge cycles ?

I have buyed recently many Li-ion protected from AW (18650, 17670 and RCR123), and the voltage at the end of charge is, depending the cell type, 4,16 - 4,20V, wich is in the safe range.

Why does the W-E cells overcharge a little ? It has also, like the AW cells, over charge and over discharge protection, in addition of short-circuit and over-current protection.

Maybe the over charge protection is setup to a higher level.

I know the Ultrafire charger is cheap, but for this price range, it does a great job with the AW cells. Why not with W-E cells ?

I don't think the charger will dramatically shorten the life of my W-E cells, but I want to be sure.

Thanks.

 

[VidPro]

IMO its not "to high" many devices use that as the max charge level.
if the charger is a constant current constant voltage type of charger, the final "toping" of the charge occurs after time, and sometimes after the "green light" shows.
so pulling early, or pulling as soon as it goes green, can bring it off the charger at a lower voltage.

lots of SPECS for li-ion used to say 4.25.
It is alwasy important to check the specs on the SPECIFIC cell you purchaced, does it say 4.25?

some Cutoffs on protection curcuits (Last chance protection) were set for 4.35, which gives a slightly lower resting than that.

there is a thread that discussed some "ultrafire" charger, where people were getting higher than 4.25v, probably would be good to search for that thread, as there is more info and opinion.

 

[VidPro]

this one would be a good thread for that, i think.
https://www.candlepowerforums.com/threads/154222

 

[Flash007]

I've pulled the cells immediately after led status goes green.

I've already read the different posts about the charger WF-139, it's why
I don't left the cells in the charger after led is green, knowing it can overcharge the cells.

W-E cells are 3,7V Li-ion, like those from AW.

 

[VidPro]

ok, i dont do abbreviations Li-ion is all pretty much the same chemistry and reaction to thing.
what is a W-E, and what is its total capacity max?
and if you know it what is its rated discharge?

Cause, i will try an esplain, a Cutoff can cutoff at a specific voltage, that voltage can be WHEN the power is on the cell (charging) then the cutoff occurs, and the cell then rests.
Different cell capacities (mostly) will rest at a different voltage when cutoff at the same voltage.
BECAUSE
the cutoff was WHEN it was charging, or the green light (in this case) shows the voltage high during a charge cycle. there is no Pulses in most of the cheap li-ion chargers, so there is no rest to do a voltage test.

someday i will say that so it can be understood

 

[VidPro]

Oh oh,,, ok, i get it. its a 18500, larger capacity than your little ones.

here is the logic, see if I can follow it.
if you put a tiny low capacity battery in ANY charger, when the charge voltage hits the battery, the voltage Seen, will go up conciderably.

if you put a Fat High capacity battery in any charger, when the charge voltage hits the battery voltage seen , will not go up as high.

its that "resistance" of the battery again.

hit a leetel battey with some juice and the total curcuit voltage will rise.
the chargers like this one, are reading the voltage on the total curcuit, WHEN the power is going to the battery.

SO (assuming you got that far)
The biger and more capacity and better "resistance" (low) your battery is, the slower the charge voltage will peak, and the higher the rested voltage will be.

also a protection curcuit, and its connections will add in a Bit of resistance, this resistance will allow the charge voltage to VIEW a bit higher, than the battery, so again the charge will be cutoff sooner, and the battery will rest lower.

 

[Flash007]

Great explanations,

First a little difficult to understand, but after reading twice, it's OK.
Thanks.

 

[SilverFox]

Hello Flash,

There was a study done showing cycle life versus charging voltage. Charging to 4.1 volts gives you around 1500 cycles. Charging to 4.2 volts gives you around 500 cycles. Charging to 4.25 volts gives you around 250 cycles.

Tom

 

[Flash007]

Thanks Silverfox !

250 cycles is OK to me.
Good for some years use before replacing the cells !