Interesting question on chargers (RCR2)

Since I bought my Xtar VC2 on Amazon, I got a question yesterday about recharging CR2 cells with it. I looked around, first to find out that there actually are rechargeable CR2 cells, and second about the needs to do so properly and safely. From what I found I couldn't really tell if it would work or not, so I recommended the questioner look for a charger explicitly designed to charge CR2 cells. My question is, is this something any charger that can do LiFePO4 cells can do? I will never need to know, but now I'm interested in the answer.

Re: Interesting question on chargers

Technically speaking, there are not really rechargeable CR2 cells.

I realize that they do make and sell "rechargeable CR2" batteries, but really these are just cells of similar (but not identical) size / shape / voltage, of varying chemistries.

The reason this is important, is that the correct charger would critically depend on the actual underlying specifics, regardless of whatever happens to be printed on the wrapper :hairpull:

Re: Interesting question on chargers

About a year ago I bought 4 of them to tryout in an alarm application. They are 3.0V nominal and exactly the same size as CR2 primaries. I am 99% s sure that they are regular 3.7V LiIon cells with some type of circuitry that drops the voltage down to 3.0V, I can see the cap through the wrapper and nowhere does it indicate LiFePO4 on the cell. I charged them up with the same target volt as LiFePO4's and a 5mA termination but lowered the current from 1C to .5C to match LiIon recommendations. So far so good. I do not know what the charge current choices are available for your charger it may not go low enough. The batteries I have are 200mAh capacity so 100mA is .5C.

Re: Interesting question on chargers

The VP2 does 0.25, 0.5, and 1.0 amps. Since I have several 10440 and 14500 lights I didn't feel like charging them at 1 amp, which was as low as my other charger went. So I got the VP2 just for those cells'
According to Wikipedia, the equivalent size to a CR2 is either 15266 or 15270. The primary CR2 is nominal 3.0v, and the Li-Ion ones are nominal 3.6v, which leads me to believe they are probably LiFePO4, but without one to look it, who knows. If that is the case, then the VP2 should do the job, but I am unwilling to say so until I actually see a rechargeable cell to check it out.l

Re: Interesting question on chargers

I have seen 15266 in both ICR and IFR (both with and without a voltage limiting circuit)

There is apparently also IMR 15270, but I haven't seen any in the 15266 size

Timothybil said:

.... I got a question yesterday about recharging CR2 cells with it....

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Added "RCR2" to the title, by the way ...

archimedes said:

Added "RCR2" to the title, by the way ...

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Thanks. Didn't think I had put that there, but you know how it is when you get old!

Timothybil said:

Thanks. Didn't think I had put that there, but you know how it is when you get old!

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Yes, since I'd guess maybe half of all the threads in here are about "interesting questions on chargers"