Regular Alkaline Expiry Date Question

[ltiu]

If it says in the regular alkaline:

"use by January 2012"

What does the January 2012 mean really?

Is that the same as half-life? As is by January 2012, the battery will only have 50% of it's original charge left?

OR

Does it mean the manufacturer cannot guarantee the performance of the battery after January 2012? It may still work after that date?

 

[WildChild]

I think you still get a decent capacity after expiracy but I also think they are more prone to leak.

 

[Fallingwater]

I think it means it'll have about 80% charge by that year.

But you can definitely use them later. I found a few Duracell alkalines still in their package that were bought new ages ago and completely forgotten. They expired in 1996.
They surely don't have anywhere near their full capacity left, but they measured slightly more than 1.5 volts on the multimeter.
I put them in my helmet headset and they work fine.
Granted, the headset draws very little current (seven milliamps). A flashlight would probably torture them to death pretty quickly.

 

[Illum]

from experience....the date is the expected shelf life from the battery, but often they leak before getting that far probably from temperature differences

I have, however, forgotten cells and later found them still intact in the package that works long after the passing of the expiration date [AA's from May 2006 bought several years earlier, for example, which is still powering my propolymer]

I think its a conditional manufacturer guarantee, conditional because it depends on the temperature in which its stored

EDIT: fallingwater, you found 1996 cells too? kool