18650 batteries trashed after two uses?

[mksmith713]

OK, I'm a newbie here so maybe someone can help me understand this.
I bought a P7 Cree flashlight that came with 2- 18650 batteries and charger.
I used the light once, charged the batteries, used the light briefly, then put the light on the shelf (I forgot to take the batteries out) and left it there for 2 months.
When I went to use it, the batteries were trash.
They won't charge.

They're not protected batteries.
Just generic blue wrapper, non descript batteries.

Can anyone explain this?
Just curious.

I've since ordered 4- protected batteries with storage cases.

Thanks in advance for any and all input.

 

[Black Rose]

Without knowing what the light was and whether it has a parasitic drain, it's difficult to say whether the cells just discharged (Li-Ion batteries should not self discharge like that) or if the light drained them and over-discharged them.

If you have a DMM (if you are using Li-Ion cells, a DMM is a "must have" accessory) check the voltage of the cells.

What is the charger you are using?
Some chargers will not charge cells if they are below a certain voltage.

In general I think it's safe to say that the cells included with the light probably weren't that good to being with.

What cells did you buy to replace them?

 

[Bullzeyebill]

Some chargers will die if the cells are reversed in the charger, or will not initiate charging until polarity is correct, if the charger has polarity protection. You must have a good voltage meter or DMM when working with Li-ion cells.

Bill

 

[csshih]

Black Rose And Bill provide good information

I also have another point to add-- you said it was a Cree p7 light? I'll assume it was a ssc p7 light.
With that, these higher output light draw a decently large amount of current- you do not want to be using junk batteries in a light like that. I think you should trash those blue cells regardless of being able to resurrect them.

 

[mksmith713]

I bought the Grey UltraFire 2400mAh 3.7v from DX.
I only use the light periodically for scuba diving.

 

[mksmith713]

It was a SSC P-7 SXO.

Here's the link to where I bought the light.

Diving Cree SSC-P7-C-SXO 3-Mode 900-Lumen LED Flashlight Kit (2*18650/4*CR123A/4*16340) [E25077] : BestOfferBuy.com, Buy DVD, Shop for PC accessories, Discount MP3 Players, Bargain Deal for Surveillance Equipment, Cheap R4 for NDS, X-sim Unlock

 

[amigafan2003]

I agree with what the previous posters have said.

You could also have overly drained the battery in your first use and damaged it. This is why protected batteries are reconmended - at least for newbies who aren't sure about the run time of thier flashlights of lights that don't have inbuilt cell protection.

Without a DMM you'll never know - you should ALWAYS check the voltage of a li-ion cell before charging and when it comes off the charger.

Below 2.75v when about to charge = dispose of it responsibly it or be very careful when charging and watch it like a hawk - any noises or warming of the cell - dispose of it.

Above 4.25v (4.2v ideally) when fresh off the charger - get a better charger.

I've since ordered 4- protected batteries with storage cases.

Not Ultrafire I hope?

 

[Lighthouse one]

The AW IMR 18650 batteries work great with a P7. The can handle high current drain, and do not have the problem of dying if the battery is run down too much. They do not have as much capacity though!