Young LiIon 3.95 Volts Max

[jayflash]

After only a few charging cycles on a DSD charger, one of a pair of protected 17500 AW cells won't charge over 3.95 volts. Charging it alone doesn't help. I've always made sure that each of the cells had an equal charge before using in my TL-3/Litho123 combo. They were always charged before reaching 3.7 ocv and the protection never tripped.

Just one of "those things" - a below par cell that finally failed?

 

[SilverFox]

Hello Jayflash,

A couple of possibilities come to mind. The cell could be used up, or there could be a malfunction of the protection circuit.

Tom

 

[max52]

If you have another charger you might try it. The weakness of the Ultrafire(continued tricke charge) might bump the voltage. Does't the DSD continue to tricke charge?

 

[jayflash]

Thanks for the input, Fellows. I'll see what happens to the cell with more use and a different charger. Maybe I'll bypass the PCB if no change occurs.

This cell should not be at the end of its life but, along with reduced capacity, depressed voltage is another indicator of old LiIons - correct?

 

[mdocod]

take it off the charger, and use it for a moment in a light (like just a second) then retest the voltage of the cell.

I have some 18650s that come off the charger at 4.00V every time, but when I somehow "toggle" something to change in the protection circuit by running them for a moment, they immediately read 4.200V. go figure.

 

[jayflash]

mdocod, I'll keep your "toggling" trick for future reference. Unfortunately, a different problem must exist for this cell.

Thanks again, Guys.

 

[chevrofreak]

My most recently purchased DSD charger won't take the cells above 3.99 volts.

I wonder if your charger is undercharging like mine does.

 

[Paladin]

take it off the charger, and use it for a moment in a light (like just a second) then retest the voltage of the cell.

I have some 18650s that come off the charger at 4.00V every time, but when I somehow "toggle" something to change in the protection circuit by running them for a moment, they immediately read 4.200V. go figure.

I had done a couple of shallow discharge cycles, then tried running the pair of P18650's closer to the dimming point. When the light finally blinked out, one cell read "0" volts!? After reapplying external voltage the protection reset, and the dead cell measured 2.95 volts.

Almost exactly 5 hours later the W139 charger lights went "green". Argg. Both cells now measured 4.00 volts. Thinking quickly I tried placing the cells under load momentarily. BINGO. Both read 4.20 vDC.

I was concerned more about overcharging than excessive discharge. The protection circuits appear to work quite well in either case. The freshly charged the AW P18650 Li-ions are delivering 2.65 amps into a P91 lamp and the beam is very white, so much so that my M3T on fresh primary cells looked "weak".

Paladin

 

[Raoul_Duke]

My most recently purchased DSD charger won't take the cells above 3.99 volts.

I wonder if your charger is undercharging like mine does.

Same for me aswell, still I quite like it, as I actually need a charger that only goes to 4V.

 

[jayflash]

My DSD charges to 4.1 volts, except for the one cell, so I suspect the cell is faulty.