A primary is just a regular non-rechargeable like you would buy at the store.
I see what you mean about the 3.6V cutoff. I would still air caution, the chinese have a weird way of phraseing things. Might be saying 3.6V is the max so do not charge past 3.6V. The guy that posted the charge graph pics thinks they might be LIFePo4 cells (read below),and most battery forums say that their is no CR2 with a protection circuit. So err on the side of caution. I might build a little charging box lol even for my regular e-cig batts. I know they are not protected and the price of those CR2s are worth the build.
These do appear to be LiFePO4 cells.
Posted by 74Sharps on 4/24/2008
Involvement: General (knows how to use it) - Ownership: more than 1 month
Price:
Ease of Use:
Build Quality:
Usefulness:
Overall Rating:
Pros: Good price
After a couple charges, all cells seem to work well.
Cons: There is some performance variation between cells, but they seem close enough.
Other Thoughts: After running six cells through a battery analyzer I've come to the conclusion these are LiFePO4 cells. Their labeling (except for the "800mA"), green jacket, and the performance figures seem to verify this.
The six cells I purchased average just under 200mAh capacity @300mA drain. This would be inline with LiFePO4 cells in a CR2 package.
I've uploaded a graph for all cells (#'s 4 and 5 are represented here by their second run) and a graph of cell #5 after it's initial charge (5) and after it's second charge (5a).
The graphs for cell #'s 1,2,3 and 6 were done after the initial charge. Two of the cells (#'s 4 and 5), after the initial charge, appeared to be under performers. After a second charge they seemed to improve and were inline, more or less, with the other 4 cells.
Bottomline: For the cost DX has a good deal here. I might caution, that if these really are LiFePO4 cells (and, as I said, I believe they are), a proper charger is in order. A 3 Volt charger designed for voltage corrected (IC'd)regular Li-Ion cells will probably work, but decrease the cycle life of the cells, as they charge to 4.4-4.5 Volts. A regular Li-Ion charger with it's 4.2 Volts would probably be better, but still grossly overcharge the cells. LiFePO4's are somewhat tolerant of overcharge, but I wouldn't recommend it. A proper LiFePO4 charger charges to 3.6 Volts. I used a WF-138, set for 3 Volts, for the tests.
Another subject, I'm not too sure about using magnets with LiFePO4 chemistry, to permit charging in a CR123 or other charger. Fe is iron. Hummm. I used copper spacers with my WF-138.
Oh, and one more thing, "Beware of experts".
I see what you mean about the 3.6V cutoff. I would still air caution, the chinese have a weird way of phraseing things. Might be saying 3.6V is the max so do not charge past 3.6V. The guy that posted the charge graph pics thinks they might be LIFePo4 cells (read below),and most battery forums say that their is no CR2 with a protection circuit. So err on the side of caution. I might build a little charging box lol even for my regular e-cig batts. I know they are not protected and the price of those CR2s are worth the build.
These do appear to be LiFePO4 cells.
Posted by 74Sharps on 4/24/2008
Involvement: General (knows how to use it) - Ownership: more than 1 month
Price:
Ease of Use:
Build Quality:
Usefulness:
Overall Rating:
Pros: Good price
Cons: There is some performance variation between cells, but they seem close enough.
Other Thoughts: After running six cells through a battery analyzer I've come to the conclusion these are LiFePO4 cells. Their labeling (except for the "800mA"), green jacket, and the performance figures seem to verify this.
The six cells I purchased average just under 200mAh capacity @300mA drain. This would be inline with LiFePO4 cells in a CR2 package.
I've uploaded a graph for all cells (#'s 4 and 5 are represented here by their second run) and a graph of cell #5 after it's initial charge (5) and after it's second charge (5a).
The graphs for cell #'s 1,2,3 and 6 were done after the initial charge. Two of the cells (#'s 4 and 5), after the initial charge, appeared to be under performers. After a second charge they seemed to improve and were inline, more or less, with the other 4 cells.
Bottomline: For the cost DX has a good deal here. I might caution, that if these really are LiFePO4 cells (and, as I said, I believe they are), a proper charger is in order. A 3 Volt charger designed for voltage corrected (IC'd)regular Li-Ion cells will probably work, but decrease the cycle life of the cells, as they charge to 4.4-4.5 Volts. A regular Li-Ion charger with it's 4.2 Volts would probably be better, but still grossly overcharge the cells. LiFePO4's are somewhat tolerant of overcharge, but I wouldn't recommend it. A proper LiFePO4 charger charges to 3.6 Volts. I used a WF-138, set for 3 Volts, for the tests.
Another subject, I'm not too sure about using magnets with LiFePO4 chemistry, to permit charging in a CR123 or other charger. Fe is iron. Hummm. I used copper spacers with my WF-138.
Oh, and one more thing, "Beware of experts".