Nooby question…

[flash_bang]

Well, I got a multimeter, and I tested 8 batteries with it. All primaries. all 123's Nuon Brand.

I was wondering, at what voltage is the battery "really" dead, dead enough to not power led's and dead enough to not power incans. My only light I'm using these for is my G2 incan.

I got some weird readings. I got the following:

2.78, 2.84, 2.88, 2.9, 3.04, 3.13, 3.27, 3.28

I was also wondering how far apart can the voltages be between the two batteries for them to still power the light and NOT vent.

Thanks much!
Flash

 

[SilverFox]

Hello Flash,

Open circuit voltage is not the best way to check primary CR123 cells. You can get some idea, but it does not tell the whole story.

I just checked a dozen cells of various brands that I have and they were in the 3.3 volt range. I believe this is closer to "normal" for new cells.

You can get a better indication by putting a load on the cell and checking the voltage under load. The ZTS tester uses a pulsed load to minimize the drain on the battery. Other people utilize flash amps as a measure. If you go with the flash amp method, remember that it is not a good idea to directly short a battery. Make sure there is a little resistance in the circuit. Usually the volt meter and leads will give you that little resistance.

You can do a search on flash amp measurements for more details on how to do it and what results you can expect from it.

To avoid venting, you need to match cells within 10% - 20% of capacity. Unfortunately there is not a good way to go from open circuit voltage to capacity.

If I had a set of what appears to be mismatched cells, I would use them only part way, then replace them. If you light is supposed to run 60 minutes, I would only use it for 40 - 45 minutes before replacing the batteries.

Tom