How to prolong battery longivity?

[aviography]

What is the best way to extend the lifespan of the T60 batteries? i.e. not how long each charge will last, but how long to keep the battery in good condition.

More specifically:

- Should I keep the battery topped up all the times with the AC adaptor connected?

- Should I let the battery run down to minimum level ever so often and then recharged it?

- Should I keep the AC adaptor connected to an UPS and just take the T60 battery out?

Granted maybe this is not as big a problem as a few years ago when litium Ion laptop batteries are up at several hundred dollars range each, but it would still be good to know of any advices to keep the batteries in top conditions longer.

TIA

[taob]

MODS: This post should probably be moved to the general hardware forum.

I was just about to ask about battery longevity (not "longivity" ) since I have three 9-cell batteries for my T60. From what I can tell, you should store lithium ion batteries partially discharged. I don't know the best charge level though, so I took a wild guess and picked 80% of a full charge. I set the TV Power Manager to begin charging the battery and 75% and stop charging at 80%.

My T60 stays plugged into AC most of the time, which means it isn't running on the battery at all. So rather than leave the battery fully charged the whole time, it sits at a more comfortable 80%. The other two batteries are also stored at 80% charge.

If I know I will be needing substantial battery power, I'll change the Power Manager settings to go to 100%. I also ordered an external battery charger for situations like that, but I have not received it yet.

I'm also told that storing batteries in a cooler place is better for them too. This would suggest that if you are running your laptop off AC most of the time, you should pull out the battery so it stays cool. Just remember not to unplug the AC if you decide to go mobile.

[leegaard]

www.batteryuniversity.com

Gives good advice

[taob]

Most of my information is taken from Battery University. They recommend storing lithium ion batteries at 40% charge levels. Although this may be optimal, it is not practical for most of us, unless we are satisfied with less than half the expected run time!

The articles mention "prolonged storage", but that is not defined anywhere. Does that mean 1 day? 1 week? 1 month? 1 year? Is it okay if I store my 9-cell batteries at, say, an 80% charge for two weeks? Or should I always discharge them to 40% if I don't think I will use the battery in the next 24 hours?