How do I preserve battery life?

My T60 won't run at full cpu speed unless the battery is plugged in, so I keep the battery in even when on AC. To increase the battery life, when on AC, I set the power manager to charge the battery only when it goes below 30% and to stop charging at 40%. Is this good or shoud I change the thresholds?

When I power up the laptop, I must plug it to AC only after it enters windows otherwise it would charge the battery up to 100%. So there is a small time interval when the laptop runs only on battery every time I power it up. Is this going to shorten the battery lifespan?

 

I think you should just set recharge percent back to default (~90% . You may be prolonging the battery life, but it probably won't make a huge difference. Lithium-Ion batteries are smart batteries. Just set it and forget it.

 

Lithium ion batteries (and most others) have their working life expressed in charge cycles. So top-ups of a few per cent count the same as top-ups of many per cent. If you have the facility to lower the threshold at which recharge starts then that is good because you can then increase the time between the charge cycles.

John

 

Yes and in order to preserve more battery life, you might want to try undervolting.

 

So your CPU wont run at full speed without the battery even when it's plugged into an AC outlet?

That's strange.

 

All rechargeable batteries do have a finite lifetime in terms of charge cycles, but it's not just a simple count of cycles. The depth of cycle is important, too. When battery companies specify the lifetime in cycle count, that's done at a fixed depth of discharge/recharge just to make it simple. A battery can survive many more small top-off cycles than full depletion/recharge cycles. So, leaving the default settings alone will still give good lifespan and also provide a fully-charged battery at a moment's notice if the system has been plugged in. I've used ThinkPads in docking stations for many years, and more recently in extensive travel environments, and I have yet to wear out a battery in under 3 years of use. My usual practice is to plug it in whenever possible.

Maximizing battery life is more a question of minimizing the power consumption by using good power management strategies. I've personally never gone as far as undervolting, but that should help as well, if you're on a quest to squeeze every last bit of use time and overall life from your battery.

 

Yes, from what I've read on the internet it's a "feature" of some chipsets. Few people observe this on their thinkpads since 979 Mhz is already fast enough for most applications.

The power manager on my laptop only counts a cycle if it's a full charge.

Anyway the question is what is more harmful: keeping the battery at 100% most of the time or doing a 1% discharge every time I power up the laptop while keeping the battery level between 30% and 40%?

 

No need to worry about battery lifespan anymore . The problem has been solved: http://forum.notebookreview.com/showthread.php?p=1958831#post1958831