Thinkpads Forum

I use my 9 cell T400 (p8400,2 GB,160 GB) usually on the mains.What are the advisable recharge parameters?.
I know some one did post tem but i dont know how to search for that old posting.
Please help, I want to recycle my laptop batteries less often...I am Green...

Most old threads you'll find on the topic will recommend 20% charging on, 80% off.

Thanks. Does it mean that charging the battery beyond 80% (which actually takes a lot of time as it saturates to 100%) actually
is at the cost of a lower lifetime of my precious battery box.?
I have set it now at 20- 80 , and I will wait for 1 year to know !.

Yes, the theory is that it is not good for the Li-ion cells to keep the charge at 100% unless you intend to use the battery frequently. It is said to decrease battery life.

The above may be a good suggestion if you really almost never use your battery right now, but foresee a future situation in which your usage pattern may change towards more extensive utilization of the pack.

Otherwise, if you typically use the laptop on the road, you have to ask yourself whether you are willing to permanently sacrifice 20% of your battery life (and much more when talking about usable battery life, since setting it to start charging only under 20% will often leave you working off AC but not charging the battery, and as a result, when you do need to run on battery, it may only hold 40% or 30% and not 80% or 100%...), and all this so that maybe your battery maintains its capacity for longer.

T400plus wrote:Does it mean that charging the battery beyond 80% (which actually takes a lot of time as it saturates to 100%) actually is at the cost of a lower lifetime of my precious battery box.?

Well, you probably should not charge the battery up to 100% unless you have a very specific need for every second of duration on battery operation.

Personally I find that starting charging when below 80% discharge and stopping charging when it reaches 95% capacity is fine in terms of trading off battery life against the need for reasonable duration of on demand operation from battery power.

Cheers,

Bill B.