In my T60 they have something called Tips for Maximizing Battery Lifespan in the Power Manager Help. I suggest you look for that. I just changed my charging scheme from full charge to maximize battery life span. The computer will automatically adjust the threshholds to accommodate this strategy. I was trying to do this by myself before. I tried to not charge to 100%, for instance. Now the computer will do this for me and presumably choose the optimal maximum charge, something well below 100%. My concern is certainly not maximum running time on battery, it's battery longevity.
The tips say something like this:
Your ThinkPad battery is a consumable component that decreases in performance over time. Here are some tips to help you maximize the lifespan of your battery:
Make sure you are using the correct ac adapter for your ThinkPad model. Using the wrong adapter will prevent the battery from charging fully and may cause the battery gauge to be inaccurate.
Do not place your battery or your ThinkPad computer in a high temperature environment.
When you store your battery outside of your computer, store it with a charge of less than 50% to reduce the battery deterioration.
If you primarily use your computer with the ac adapter attached and only infrequently use battery power, battery deterioration may occur faster when the battery is constantly charged at 100%. Lower the charge thresholds of your battery if you use your ThinkPad computer often while on ac power. Learn about changing the battery charge thresholds.
If you have a Li-Ion or Li-Polimer battery, learn about resetting the battery gauge.
If you have a NiMH battery, learn about conditioning the battery.
Use Power Manager to select the best power scheme for you. Learn about using Power Manager.
Note: If it has been a long time since you last charge your battery, it will take longer to charge.
Note: Battery performance will be temporarily be degraded if the battery is used in a cold environment.
Note: When the computer uses a large amount of electricity from the battery (for example, for intensive calculations or high-end graphics applications), the temperature of the battery and the computer may rise. In this case, the battery might automatically stop charging to so that the battery operates at a level that ensures comfortable usage and normal battery life. When the battery is restored to its normal temperature, the battery will start to recharge.
Links (in the actual help)
Battery characteristics
Checking battery health condition
Changing battery charge thresholds
Resetting the battery gauge
Conditioning a NiMH battery
Using Power Manager
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----> The default charging scheme is not to maximize the battery life but to charge the battery to the max. I suggest changing it like I just did to the self-adjusting scheme that maximizes battery life.