milkyspit
Flashlight Enthusiast
The other day I received my shipment of 100 Tekcells from Countycomm. Nice deal at $75 shipped! But when they arrived I noticed what looked like an orangish discoloration like some sort of leakage around the base of a few of them, and this prompted a test. Being sort of a thorough individual, my little test quickly became an afternoon of detailed examination worthy of inclusion in Consumer Reports! I had better things to do with my time, but the results were certainly interesting. Oh well. /ubbthreads/images/graemlins/icon3.gif
My single big insight on that day was that 123 cells behave a little differently from the alkalines we all know and love; namely, an alkaline cell's voltage will steadily decrease during its lifetime, while even a heavily depleted 123 might still deliver 2.8-3.0V. So while alkalines can be checked quite nicely by examining their voltage with a DMM, 123s cannot.
What does happen to a 123 is that its maximum current flow capability steadily decreases as it runs down, so a test of momentary unloaded current flow (let's call that MUC throughout the remainder of this article) using a DMM yields what appears to be very nice information about the condition of any given 123. Before getting to specifics in my test, note that this measurement can be taken using a DMM set to a high current range, by touching the probes to the terminals on the cell and holding *just* until the peak current reading appears. You'll see the current reading jump upward quickly, peak at some point, then gradually begin dropping. All this takes a fraction of a second, after which REMOVE THE PROBES! Longer than that could damage the 123 cell.
As I started going through my 100 Tekcells measuring MUC for each, I came to 'bin' the cells based on their readings. I assigned bins at each amp boundary, so 7.0-7.9A would represent one bin, 8.0-8.9A would represent another bin, etc. Here's what I found for my 100 Tekcells as shipped:
Bin (number of 123s)
0.x (2)
5.x (3)
6.x (4)
7.x (33)
8.x (58)
Given these results, I established 7.0A as the minimum MUC that indicated a 'fresh' 123, and as seen by my results, variance among Tekcells was only fair, with several not shipped fresh and two dead as a doornail!
Now I was curious, so I measured my other 123 cells, which consisted of 18 Surefires and 2 Sanyos. Here's how they binned:
Bin (number of 123s)
9.x (20)
So the first conclusion I drew was that Surefire cells really do give you something more for your money! In two ways, really; they ALL binned higher than the highest Tekcell, and the variance was MUCH tighter, suggesting stricter quality control. As for the two Sanyo cells, the results certainly were encouraging, although I don't feel comfortable drawing a conclusion from a sample size of two.
So in the first part of my analysis, I concluded that I didn't get all I bargained for with my Tekcells. But did I get enough? Let's look at the economics involved.
The Tekcells came with no shipping charge, and if I buy enough Surefires at once, they also come with no shipping charge. So looking strictly at the cost of the batteries, the Tekcells cost $0.75 each, whereas the Surefires cost $1.25.
For my money, I really only got what I'd classify as 91 'fresh' Tekcells, so they effectively cost me a little over $0.82 per 'fresh' cell.
Now being a little severe on the Tekcells (you'll see why soon), I'll estimate that I can only depend on getting 7.0A MUC from each Tekcell, whereas I'll assign 10.0A MUC to each Surefire cell. Let's further assume that MUC is directly proportional to the usable power capacity of a 123 cell.
This means those 91 fresh Tekcells really cost me $1.18 for the same amount of power capacity as I got from each $1.25 Surefire cell. This was calculated as $75 divided by 91 Tekcells, times 10A/7A (to account for the higher power capacity available in the Surefire cells). Even with the bad cells and the lower binning of the Tekcells, they still seem to be worthwhile.
So who wins? Well both, sort of, but it depends on your needs. If you simply want the most power capacity for the lowest unit cost, go for the Tekcells, which for all their problems still price to about $1.18 for what costs you $1.25 from Surefire. On the other hand, if you're going for the longest runtime before having to reload your flashlight, or for the greatest likelihood that the next cell you grab isn't a dud, go for the Surefire. It makes intuitive sense that the price you pay for these niceties is an additional $0.07 per cell for the Surefire 123 vs. the Tekcell.
Each person will have their own reasons for buying, but now, at least with these brands, maybe you can make an informed choice. Hope this helps someone out there. /ubbthreads/images/graemlins/smile.gif
My single big insight on that day was that 123 cells behave a little differently from the alkalines we all know and love; namely, an alkaline cell's voltage will steadily decrease during its lifetime, while even a heavily depleted 123 might still deliver 2.8-3.0V. So while alkalines can be checked quite nicely by examining their voltage with a DMM, 123s cannot.
What does happen to a 123 is that its maximum current flow capability steadily decreases as it runs down, so a test of momentary unloaded current flow (let's call that MUC throughout the remainder of this article) using a DMM yields what appears to be very nice information about the condition of any given 123. Before getting to specifics in my test, note that this measurement can be taken using a DMM set to a high current range, by touching the probes to the terminals on the cell and holding *just* until the peak current reading appears. You'll see the current reading jump upward quickly, peak at some point, then gradually begin dropping. All this takes a fraction of a second, after which REMOVE THE PROBES! Longer than that could damage the 123 cell.
As I started going through my 100 Tekcells measuring MUC for each, I came to 'bin' the cells based on their readings. I assigned bins at each amp boundary, so 7.0-7.9A would represent one bin, 8.0-8.9A would represent another bin, etc. Here's what I found for my 100 Tekcells as shipped:
Bin (number of 123s)
0.x (2)
5.x (3)
6.x (4)
7.x (33)
8.x (58)
Given these results, I established 7.0A as the minimum MUC that indicated a 'fresh' 123, and as seen by my results, variance among Tekcells was only fair, with several not shipped fresh and two dead as a doornail!
Now I was curious, so I measured my other 123 cells, which consisted of 18 Surefires and 2 Sanyos. Here's how they binned:
Bin (number of 123s)
9.x (20)
So the first conclusion I drew was that Surefire cells really do give you something more for your money! In two ways, really; they ALL binned higher than the highest Tekcell, and the variance was MUCH tighter, suggesting stricter quality control. As for the two Sanyo cells, the results certainly were encouraging, although I don't feel comfortable drawing a conclusion from a sample size of two.
So in the first part of my analysis, I concluded that I didn't get all I bargained for with my Tekcells. But did I get enough? Let's look at the economics involved.
The Tekcells came with no shipping charge, and if I buy enough Surefires at once, they also come with no shipping charge. So looking strictly at the cost of the batteries, the Tekcells cost $0.75 each, whereas the Surefires cost $1.25.
For my money, I really only got what I'd classify as 91 'fresh' Tekcells, so they effectively cost me a little over $0.82 per 'fresh' cell.
Now being a little severe on the Tekcells (you'll see why soon), I'll estimate that I can only depend on getting 7.0A MUC from each Tekcell, whereas I'll assign 10.0A MUC to each Surefire cell. Let's further assume that MUC is directly proportional to the usable power capacity of a 123 cell.
This means those 91 fresh Tekcells really cost me $1.18 for the same amount of power capacity as I got from each $1.25 Surefire cell. This was calculated as $75 divided by 91 Tekcells, times 10A/7A (to account for the higher power capacity available in the Surefire cells). Even with the bad cells and the lower binning of the Tekcells, they still seem to be worthwhile.
So who wins? Well both, sort of, but it depends on your needs. If you simply want the most power capacity for the lowest unit cost, go for the Tekcells, which for all their problems still price to about $1.18 for what costs you $1.25 from Surefire. On the other hand, if you're going for the longest runtime before having to reload your flashlight, or for the greatest likelihood that the next cell you grab isn't a dud, go for the Surefire. It makes intuitive sense that the price you pay for these niceties is an additional $0.07 per cell for the Surefire 123 vs. the Tekcell.
Each person will have their own reasons for buying, but now, at least with these brands, maybe you can make an informed choice. Hope this helps someone out there. /ubbthreads/images/graemlins/smile.gif
