Thinkpads Forum

I have a 9 cell battery and am wondering what is the minimum battery charge that I can safely leave on my laptop for 24+ hours?

Does the battery have to be fully charged as much as possible?

The best percentage to leave a battery at is 40% for battery longevity. The worst is 0% as it might not take a charge in the future.

I don't think it really matters for something as short as 24 hours. But you don't want to forget it a 0% for a few weeks though.

My TP spends 99% of the time plugged into the advanced minidock on AC power. I rarely use battery power. I've heard this 40% recommended optimal charge level for storage from several sources.

So assuming that is accurate, and given my usage pattern, I was thinking it would make sense to set the power manager to start charging the battery when it gets down to 40% and stop charging at something like 50%.

And then whenever I will be needing the battery fully charged for whatever reason, to just change the settings several hours beforehand.

I'd appreciate any comments on this plan, especially if I'm off base or missing something.

I work for a company that buys batteries in bulk. The battery manufacturers recommend the batteries have a 40% charge when stored. However, they also recommend that the batteries be rotated into use and not stored for a long period of time.

Batteries age and with age lose their life and performance -- you can't avoid that. When I say "age", I mean a battery not being used and stored at 40% is decreasing in life and performance just be getting older.

Since you are regularly using the battery, I honestly don't think you'll extend your battery life or performance enough to justify all the hassle of trying to keep it near 50%.

The below site has some very detailed and thorough explanations. I'm no expert in battery chemistry through...

http://www.buchmann.ca/

Very interesting. Thanks for posting the link.