Ultrafire CR123 "dies but works"

[savagebunny]

Hello, I'm a little new to the Flashlight world and batteries etc. Anyways... I bought a charger and Ultrafire batteries from battery junction...

They work great, but sometimes they don't work. I pulled my multi-meter out all the times it happened.

For example from left > right on my image

#1 would read about 3.5v. Okay that's fine
#2 would read about 3.45. Okay that's fine
#3 would read such a low voltage, it would keep dropping until I got no more voltage

I though this was weird so I just today only put the one that was completely dead for about 2 minutes, pulled it out and was reading 3.5v again.

Anyone know why this would be happening? I don't know some of the correct terms maybe but I know why this happens.

Thanks, Anthony

 

[zipplet]

Sounds like you tripped the protection circuit. Putting the battery on the charger will reset it. You are running those batteries too low - those voltages you quote tell me that the batteries are pretty much discharged.

How long were you running the light before that happened?

 

[bstrickler]

Sounds like you tripped the protection circuit

+1

How much current were you drawing from the cells? The ultrafire/trustfire cells don't like more than a half-amp being pulled from them, otherwise they die rather quickly (at least my cells do).

~Brian

 

[Black Rose]

As others have stated, sounds like you tripped the protection circuit.

You had mentioned you were new to flashlights and batteries.

Here is a chart that one of the resident battery gurus came up with to indicate the state of charge on Li-ion cells.

Resting voltages (no load connected) are a good indicator of state of charge. These figures are approximate:
4.2V = 100%
4.1V = about 90%
4.0V = about 80%
3.9V = about 60%
3.8V = about 40%
3.7V = about 20%
3.6V = empty
<3.5V = over-discharged

 

[savagebunny]

Thanks for the replys.

It was the protection circuit as said. I threw them on the charger for about 2hrs and they have been running for about 2 days now with about 20 minutes of being used.

Also, thanks for the Li-ion charge chart.

 

[Monocrom]

Ultrafire battiers are crap!

Some work . . . for awhile. Others refuse to charge up. Others won't charge after the first charging they get. Others don't have any life in them when brand new.

Ultafire cells are about as stable as the sanity level in a mental institution.

Do yourself a favor and buy AW brand cells. You can find them at Lighthound.com

 

[Linger]

Caution - that continued self-discharge could be one sign of battery death. There could be several internal failures resulting in a cell not being able to hold a charge, all of them bad.
Standard test for battery health is to charge it, and see that it will hold above 4.00v. Yours isn't holding anything.
Extra caution - if you're using it in a multi-cell application, there's a high likelyhood that it self-discharges to nothing setting up the required circumstance for reverse charging from the other cells and subsequent 'age or 'venting with flame'

FYI - those cells aren't indicated for multi-cell applications. AW IMR's are great to use for multi-cell.

:twothumbsYou make me happy with your DMM and checking the cell voltages, good start.

Please look over the figures Black Rose posted - 3.6v is finished. Now we know that it's possible to go lower, and safely, but you're really cutting into battery life and reducing cycles by doing it. re-charge early, recharge often. (A long-life plan could ensure daily use takes them from 4.0v -> 3.8v and then back in the charger only to 4.0v, you should have a long service life from them.)
Read batteryuniversity.com