Gentlemen, I have a six month old Surefire G2 that still had the original Surefire batteries in it. It would not work last night so I took out the batteries and checked them. One battery was completely dead but the other still had a good charge on it. So I replaced only the dead battery and it works fine now. This is no big deal to me, but I just thought it was a little strange that BOTH batteries would not be dead. This is a great board, thanks in advance for any information. Also, thanks to all you Vets that made my freedom possible.
G2 with one of two batteries dead
- Thread starter ugrey
- Start date
js
Flashlight Enthusiast
If I remember correctly, there was a time when SF123 lithium batteries had this problem of the occasional dud cell, new out of the box untouched. i.e. a small percentage of them left the factory as duds. This is definitely what happened here, because as you point out, BOTH batteries should have been dead if there were some leakage current in the circuit--tailcap not locked out and making very very slight contact (not likely!). Oh, come to think of it, the G2 tailcap doesn't lock out, does it?
Anyway, whatever. Dud battery, not dead battey, is the explanation I think.
Anyway, whatever. Dud battery, not dead battey, is the explanation I think.
i7r7
Newly Enlightened
Actually, I have gone through probably 20 -30 sets of batteries (of all brands) with my Inova X5t and Surefire G2 P60 and P61. Nearly every time, the one battery is completely dead, the other at approximately 20-30% charge.
I'm still scratching my head over this phenomenon.
Jeff
I'm still scratching my head over this phenomenon.
Jeff
js
Flashlight Enthusiast
i7r7,
How can you tell? that is, what method are you using to determine the state of charge of the 123? Voltage? Current? An Arc LS?
Also, do you run the batteries down to almost nothing? Or do you shut off the light at the fist sign of dimming?
How can you tell? that is, what method are you using to determine the state of charge of the 123? Voltage? Current? An Arc LS?
Also, do you run the batteries down to almost nothing? Or do you shut off the light at the fist sign of dimming?
jayflash
Flashlight Enthusiast
There remains different opinions about when you should install new cells. When voltage drops to a certain level the halogen cycle becomes inactive. However, lower voltage boils off less tungsten from the filament. From what I know at this time, I think it's a wash - that it won't affect lamp life to use weak batteries. Perhaps some lamps are constructed differently and darken the globe less when running hotter on fresh cells. Whether that also extends their life is debatable.
No two cells have equal capacity, which is why it's not good to use a rechargeable light until it's very dim. One or more cells could be reverse charged by the stronger ones. Likewise, primary cells will vary in capacity and often one will die before the other. Sometimes, though, lithium cells will die, unexpectedly, while in storage, well before they normally should have. This may be due to the highly active nature of the lithium, where a minor manufacturing defect has more serious consequences than, say, in an alkaline cell.
These are just my guesses, others may have more accurate information.
No two cells have equal capacity, which is why it's not good to use a rechargeable light until it's very dim. One or more cells could be reverse charged by the stronger ones. Likewise, primary cells will vary in capacity and often one will die before the other. Sometimes, though, lithium cells will die, unexpectedly, while in storage, well before they normally should have. This may be due to the highly active nature of the lithium, where a minor manufacturing defect has more serious consequences than, say, in an alkaline cell.
These are just my guesses, others may have more accurate information.
i7r7
Newly Enlightened
I just had another set of batteries used up in my G2 P61 just a few hours ago. I tested the batteries using a multimeter. Both batteries show a voltage of 2.6-2.7 fluctuating. When connected directly to the multimeter in 10A scale, one battery reads 5.5A rapidly dropping to 4A and 3A. The other reads 0.01-0.02A. Estimated 30% for the 1st battery, 0% for the second (obviously).
Considering that the voltages are very similar, the 30% battery wouldn't be charging the other.
Jeff
Considering that the voltages are very similar, the 30% battery wouldn't be charging the other.
Jeff
