Called Sterling Tek and they said .....

U P D A T E!!

JJD.Photography wrote in post #8090049
I have 3 of the: ST51 Canon BP-511A batteries for my 50D. Work great and seem to last a long time. Never have drained one so don't really know how many shots they are good for.

3 years later...

We have 4 of the batteries between us. Not sure what happened to the other 2 (total of 6). But, 3 of the 4 we have been using are now garbage!
When placed on the charger they will show as charging, until fully charged. Then once placed in the camera either very low status or nothing at all. Our OEM Canon's have outlasted these! In the future I will buy OEM batteries.

I've got to find the 2 missing batteries...

JJD.Photography wrote in post #14890928
3 years later...

We have 4 of the batteries between us. Not sure what happened to the other 2 (total of 6). But, 3 of the 4 we have been using are now garbage!
When placed on the charger they will show as charging, until fully charged. Then once placed in the camera either very low status or nothing at all.

As I stated earlier, in post 16
" the lithium related cell is also subjected to an ageing process, independent from the usage. Lithium-based batteries have a lifetime of 2-3 years, given an optimum of maintenance. This life span starts as soon as the battery is constructed. This loss of capacity is caused by an increase of internal resistance due to oxidation."

JJD.Photography wrote in post #14890928
3 years later...

We have 4 of the batteries between us. Not sure what happened to the other 2 (total of 6). But, 3 of the 4 we have been using are now garbage!
When placed on the charger they will show as charging, until fully charged. Then once placed in the camera either very low status or nothing at all. Our OEM Canon's have outlasted these! In the future I will buy OEM batteries.

I've got to find the 2 missing batteries...

The catch is the price though, that's why I'd buy 3rd party like sterlingtek even if I knew for a fact they wouldn't last as long. They cost so much less that I can replace them as needed and still come out ahead of what I would have spent on the crazy-high priced canon batteries.

Wilt wrote in post #14891639
As I stated earlier, in post 16
" the lithium related cell is also subjected to an ageing process, independent from the usage. Lithium-based batteries have a lifetime of 2-3 years, given an optimum of maintenance. This life span starts as soon as the battery is constructed. This loss of capacity is caused by an increase of internal resistance due to oxidation."

Yeah, if the OEM batteries have lasted more than 3 years, that is a lucky thing. It is not a real complaint against the others that they "only" lasted 3 years.

getting 3 years out of a battery is really good...