Lithium coin cell longevity

[BillSWPA]

Can anyone comment on how long I can expect a lithium coin cell in general, or a CR 1220 in particular, can be expected to last when installed in a flashlight that is not used?

I use coin cell powered LED keychain lights as promotional giveaways for my business. Although they are not anything that would impress a flashaholic, I did test multiple lights for brightness and durability (by letting a 3 year old child play with the samples) before purchasing them. They have been well received, and I do try to make sure anything with my name on it is going to reflect positively on me.

After some of these have been around for a few years, they do not seen quite as bright as they were when originally received. I will probably end up ordering a bunch of cells in bulk and replacing them, but before I start this time consuming process, I was wondering what the battery gurus here could tell me about these cells.

Thanks in advance!

 

[archimedes]

CR1220 "coin" cells would use lithium primary battery chemistry, which has low self-discharge and good long-term storage characteristics.

I found it difficult to locate many specifics about longevity for this particular battery format, but the Sony data sheet suggests that they are discharge tested after exposure to high temperature for 100 days, to approximate effects of storage at room temperature for 5 years (and with little loss of capacity).

I would think that the more important factor(s) with "promotional" items using these type of cells would be (#1) what quality of cells are being used, and (#2) how "fresh" are those cells ....

 

[BillSWPA]

CR1220 "coin" cells would use lithium primary battery chemistry, which has low self-discharge and good long-term storage characteristics.

I found it difficult to locate many specifics about longevity for this particular battery format, but the Sony data sheet suggests that they are discharge tested after exposure to high temperature for 100 days, to approximate effects of storage at room temperature for 5 years (and with little loss of capacity).

I would think that the more important factor with "promotional" items using these type of cells would be (#1) what quality of cells are being used, and (#2) how "fresh" are those cells ....

Thank you for the information.

Looking at the description of a couple of good brands, depending on brand, they claim a shelf life of 5-10 years. I suspect you are correct in your observations about the quality of the cells used when they were originally made. If correct, this would mean that going through the exercise once with good quality cells, preferably ones claiming a 10 year shelf life, would ensure that I do not have to do it again until my current supply of lights is depleted and I need to order more.

 

[m4a1usr]

I have been using replaceable Lith-Ion Coin cells (CR2032) in my work HP computers for about 18 years now and got around 7 to 8 years on the first set of Maxell's (Hitachi made in Japan) and silghtly better on the second sets. About 9 years on those. Probably due to better chemistry in manufacturing. On the third set now and hopefully another 6 or more years out of them.