New Keeppower Protected 18650 only partly charges in Nitecore i2

[veganvap]

I bough these and a new nitecore i2

2X Keeppower Protected 18650 2900mAh with Panasonic NCR18650PF Li ion PCB | eBay


There're for a headlamp and I was told these are top of the line for it. I used them in the headlamp an hour or so, then charged in the i2. One charged all the way to three of three lights on the i2, the other just keeps blinking at only two lights, I had if charging for like 10 hours. I tried it on the other side of the i2, same problem. Should I ask for replacement? should I worry about the safety of this battery? Can I test it with a multimeter?
thanks

 

[Ryedan]

Test the battery voltages with a multimeter. A fully charged batt will be real close to 4.2. Let us know what you find.

 

[veganvap]

I plugged the nitecore into the wall. I was using it with a car adapter before (brand new truck battery and genuine nitecore adapter). Now instead of the questionable battery only getting 2 of 3 nitecore lights flashing, it flashes all 3 in either nitecore port but the other good battery gives solid 3 lights meaning it's fully charged.
Actually the manual doesn't really say if 3 lights flashing indicates fully charged compared to 3 solid lights because all it says is 'for safety overcharge, if a slot exceeds 20 hours, it will stop charging it and show 3 solid lights to indicate the completion of charging.'
So does that mean 3 flashing lights is fully charged? Because 20 hours seems way too long for it to kick into 3 solid lights, you would think it would go solid 3 lights after 8 hours max or something, and I've had them on for over 20 hours.

I used a cheap Harbor Freight multimeter but I've read they're fine for reading anything but resistance (I can attest to them being useless for reading ohms). Both batteries are 4.19 volts 8.4 Amps. The listing says these batt's PC board trips at 10 Amps, so I guess 8.4A is supposed to be 10A.

so overall, I guess they're fine even though one doesn't show solid 3 lights. I'm not going to bother with a refund or anything. Thanks for the suggestion

 

[Ryedan]

You're welcome

Don't bother checking amps. If the batteries are 4.18 - 4.22 volts on completion of charge they are good and the charger did its thing properly.

I don't know the Nitecore chargers well. I think you can figure out how they work though with a bit more observation. Check batt voltage when the lights do something. 4.2v is charged.

And don't leave batteries charging overnight or while you're not there. A lot of the rare battery fires that happen, happen while they are being charged.