It might just be me, but... Why would you want to kill the battery?
If I'm reading his question correctly...
Rechargable batteries develop a "memory" when charged from an already partially charged state. And i could keep you from utilizing the full life of the battery.
Running the battery completely dead before recharging ensures that you get a FULL charge on the phone.
Ah, I see. Well by completing draining the battery you are going to be doing more damage than good. Everyone concerned with batteries should read about Lithium Ion batteries.
Lithium ion chemistry prefers partial discharge to deep discharge, so it's best to avoid taking the battery all the way down to zero. Since lithium-ion chemistry does not have a "memory", you do not harm the battery pack with a partial discharge. If the voltage of a lithium-ion cell drops below a certain level, it's ruined.
Trevor is correct. Lithium Ion batteries don't have "memory."
The manual suggests "conditioning" the battery by running it down to 15-20% the first three times after charging it fully. Then after that you are better off to keep it topped off or just charge whenever you want. I charge mine every night, regardless of it's status.
I see. I read on BlackBerryFAQ that you should fully charge-discharge to 'break-in' the battery and then after that keep it fully charged. I've charged and discharged my BB twice now. So should I let it die one more time and then charge it every night or should I wait till its at %15 then fully charge it?
-Mr. Wonderful
Posted from my CrackBerry at wapforums.crackberry.com