ebow86
Flashlight Enthusiast
I have an old Surefire B90 cell that I received in a trade package I recently received on the marketplace. The seller was very honest and told me that the battery was shot. Anyway, after this battery fully charges on my stock Surefire B90 charger (the newer model that blinks green) I seem to get around 30 minutes runtime with it, a fresh new battery is supposed to get around 50 minutes runtime. Here's the issue...
What is strange is that when I do a runtime test will new healthy B90 cells the light will start noticeably dimming and getting yellow around the 40 or 45 minute mark, which seems to be quite normal. This older cell behaves a bit differently. What seems to happen is I get nice bright white output from this cell right up to around the 30 minute mark then bam, no dimming, no turning yellow, just dead. The healthy cells will always give a sign that they are getting depleted, they start turning yellow and dimming at the outer edge of their runtime, not so with this cell. What else is strange is if I run this cell for oh, say 20 minutes, shut the light off, come back in a few hours, and the cell is completely discharged.
I thought there was a possibility that the cells in the pack were out of balance so I tried keeping the cell on trickle charge for a period of 24hours, however, this had no effect. I have also discharged and recharged this cell multiple time's which didn't have any effect either. I know Surefire had some issues with the B90 cells early on, and there is a ton of info here on CPF about the matter, but I know Surefire fixed the issues a long time ago. FWIW the batch code on the cell is CM14.
I don't own a voltage meter and I don't have any way to measure the capacity of the cell so to be honest I'm not that much of an expert on batteries and there are many other's here that know much more than I do, so I am hoping some of you might have some ideas on what the issue is here.
What is strange is that when I do a runtime test will new healthy B90 cells the light will start noticeably dimming and getting yellow around the 40 or 45 minute mark, which seems to be quite normal. This older cell behaves a bit differently. What seems to happen is I get nice bright white output from this cell right up to around the 30 minute mark then bam, no dimming, no turning yellow, just dead. The healthy cells will always give a sign that they are getting depleted, they start turning yellow and dimming at the outer edge of their runtime, not so with this cell. What else is strange is if I run this cell for oh, say 20 minutes, shut the light off, come back in a few hours, and the cell is completely discharged.
I thought there was a possibility that the cells in the pack were out of balance so I tried keeping the cell on trickle charge for a period of 24hours, however, this had no effect. I have also discharged and recharged this cell multiple time's which didn't have any effect either. I know Surefire had some issues with the B90 cells early on, and there is a ton of info here on CPF about the matter, but I know Surefire fixed the issues a long time ago. FWIW the batch code on the cell is CM14.
I don't own a voltage meter and I don't have any way to measure the capacity of the cell so to be honest I'm not that much of an expert on batteries and there are many other's here that know much more than I do, so I am hoping some of you might have some ideas on what the issue is here.
