Used Lithium Batteries

[i7r7]

I know this has been discussed before on this forum but I want some conclusive replies.

I realised that Lithium (3v 123) batteries show very strange voltage and current readings, when they're nearly used. I noticed that when 2 123 batteries are used in my SF G2 and Inova X5T until they're nearly empty, they suddenly die. They always die between uses and never when I have the flashlight on.

When the batteries are tested on my multimeter, both batteries have similar voltages but the current drawn out of one of the batteries is very high (over 5A) and the other will always draw very little (less than 0.01A), when connected directly to the multimeter on the 10A scale.

I know that when batteries (or capacitors) when connected in series in a circuit, their voltages must be the same. However, how can one battery have less charge in it than the other.

Another strange thing happens if I take the batteries out and leave them on the table for a week. Sometimes, the batterie's voltage will drop significantly (down to about 0.5V or less), even the battery which was once drawing about 5A. Other times, the battery will be fine and the voltage will jump back up to 2.8V and continue to draw 4-5A for weeks to come.

I've noticed these symptoms with a wide variety of brands and quality batteries (Surefire, Sanyo, Energizer e2 and DP Power). I hate it how one moment, my X5T can provide a useable beam then next time I want to use it, it doesn't even emit a single visible photon.

Can anyone help explain the strange behaviour of these lithium batteries?

Jeff

 

[Doug S]

[ QUOTE ]
i7r7 said:
I know that when batteries (or capacitors) when connected in series in a circuit, their voltages must be the same. Jeff

[/ QUOTE ]
Jeff, not everything you know is true. /ubbthreads/images/graemlins/wink.gif
Welcome to the forum, BTW.

 

[RussH]

In ideal circuits, in series, current would be the same. In parallel, voltage would be the same. The electrons may all be identical but the batteries probably are not. I get many of the same somewhat weird occurances as you have - especially the 'They always die between uses' bit. I have run them down completely in a flashlight before. But they often die suddenly & often they die between uses.

 

[jayflash]

Greetings i7r7 and welcome to your new home - there is no escape!

For all the advantages that lithium batteries possess, they are, IMHO, the least predictable of the various cell chemistries. Some seem to last "forever" and fade to black while others give 30% of rated capacity and die while unused. I'm guessing that manufacturing vagaries/QC issues cause an occasional cell to freak out. I have had some alkalines quit before they should have but never die when the light was off.

This problem has frustrated many (but not all) of us CPFers. Like most others here, I carry extra batteries no matter what kind I'm using for the flavor-of-the-day.

Looking forward to your future contributions i7r7.

 

[eluminator]

I find the 123 cell in my ARC LS will often die overnight just sitting on the night stand. It worked fine yesterday and today it's in moon mode. Sometimes the battery is almost new, having been used for only a few minutes.

The Sanyo I'm using now has lasted over a month. But the previous one lasted only a few days. If I have any more of these premature failures, I will start carrying the 2 AA cell version.

 

[georges80]

There is one definite 123 issue that I'm not sure is well known.

Draw lots of current >1A from a 123 and it gets HOT. When hot, the chemical reaction is enhanced and the output voltage (at a given current) will increase. So, everything is great, light is running and you think, wow, I'm getting great runtime out of this puppy. Then put it away and it cools down - chemical reaction is now 'slow'. Apply the load again - and - wham the 123 output voltage drops like a rock and your light is dead because the switcher can't start up.

Presumably a lot of these high drain/over driven LED lights are drawing easily in excess of 1A from a 123 to fire up those flame throwers CPF folk seem to love.

george.

 

[i7r7]

My fault, I think it should be "batteries (or capacitors) when connected in series in a circuit, their CURRENT must be the same." (Should have paid more attention during physics class) That should mean that the batteries have different capacity (or charge). But that also means that in one case, one of the Surefire batteries must have had double the capacity than the other.

Yeah, bad quality control could be the culprit but it seems that every set of batteries have turned out to be duds. I admit that I'm not a flashaholic yet and I've only gone through about 10 pairs of 123 batteries.

Yeah, heat damage could also be the culprit but half of those batteries that I've used were in my Inova X5T. It barely draws a quarter of an amp. However, I can believe that heat damage could have destroyed my batteries in my SF G2 with P61 which draws 2.25A.

Jeff