Uneven Battery Usage?

Hello,

I had to replace the 3 SF123 batteries in my SF C3 the other day. Out of curiosity, I measured the voltage on the three batteries: 2.80 v. I also was curious on the current, so I measured it briefly on the 20A setting of my DMM. Two batteries put out 4.5 amps and the third only put out .3 amps!

Is this common? How much life is left in those first two batteries? Does this happen in a two battery configuration, too? Does the uneven usage pattern get more pronounced with more batteries in the light? How do I get even usage so I can use all the juice in the batteries?

Thanks,
Patrick

Hello Patrick,

Not sure why this happens, but it does happen. One thing I have heard of, and do myself, is to rotate the batteries between uses. Sometimes it is the battery closest to the lamp that dies first, and other times it is the one near the tail cap. I believe there have been more reports of the lamp end battery dying first.

I think you need to use up the other batteries in a single battery light, although I have been known to put a fresh cell in for the dead one and go on using the light.

Tom

So I could probably increase my runtime during a single run by changing the positions in the tube? Maybe every half hour or something? I'll certainly start changing the positions between uses.

Hello Patrick,

I should add that all of this cell swaping idea is theory.

Why don't you keep notes and see if a proof emerges...

Tom

I believe I started a thread a while back and a lot of people gave us theories based on the observations. I don't recall most of it though.. /ubbthreads/images/graemlins/grin.gif

I think it is this one. Thanks for the background.

I'll toss out a guess that at 4.5 ("flash") amps, the other two cells won't last much longer. My experience has shown when CR123's get below 5 amps the end is near. Of course, I've also found some exceptions to this.

How long did those two cells end up lasting?

BTW, I doubt that swapping the cell's positions every half hour will make a difference. The exception to this might show up if the light produces a LOT of heat and is used for extended runs. I could be wrong and I'd like to hear of others CPF member's experiences, but I haven't found any advantage to cell-swapping for the way I use my lights.

[ QUOTE ]
jayflash said:
I'll toss out a guess that at 4.5 ("flash") amps, the other two cells won't last much longer. My experience has shown when CR123's get below 5 amps the end is near. Of course, I've also found some exceptions to this.

How long did those two cells end up lasting?

BTW, I doubt that swapping the cell's positions every half hour will make a difference. The exception to this might show up if the light produces a LOT of heat and is used for extended runs. I could be wrong and I'd like to hear of others CPF member's experiences, but I haven't found any advantage to cell-swapping for the way I use my lights.

[/ QUOTE ]

Ahh, so maybe it's not such a big difference? I haven't had any other lights run down to the point that I could put these in and get more light. I probably should swap them out just to see.

I should just swap them out when I get home tonight and let one of my 1x123 lights shine at a wall. Would be cool if I could get a runtime plot, but I don't have a light meter.