Thinkpads Forum

I received my replacement battery (from the recall) and this behaves differently than my previous battery.

I don't typically venture away from ac power and the battery slowly drains. It slowly trickles down every couple days...100%, 99%, 98% etc...

Is that normal or do I possibly have a dud?[/img]

I believe it will go down to 96 and either charge back up or stop there.

You might try to click the battery gauge in the task bar and choose "Remove and Replace Battery" then go through the procedure to make sure that the status is reset properly in both the battery and the system.

All batteries will decay their charge at a rate that varies on the technology in question. Lithium Ion is one of the faster ones. The single-use alkalines are some of the slowest.

The Thinkpad power manager allows the user to specify hysteresis (i.e. a delay in triggering an event) in its charging settings, so that batteries are only charged a few days, instead of constantly every time the power level drops measurably from 100%.

I strongly recommend not attempting to keep the battery at 100%. Lithium Ion batteries (like most older technologies, too), like to be charged up from as close to the drained-point as possible. (Note that even the drained-state isn't really drained, it's simply the point at which the battery still responds to power demand and where it still be charged back up.) While that's not feasible for most users, the problems of constant recharging can be reduced by only charging the battery when there's more than just a minimum measurable drop in charge. Hence the 96% or so hysteresis point.

If you are concerned about not getting as much working time on your computer, trust me that the few percent won't translate into much of anything, as the battery charge state indication is not entirely linear. The useable time of the first few percent is far less than the same towards the very end of the battery charge.

Thanks for the responses

I wasn't concerned about not getting as much working time, just curious about whether or this was normal since I have not seen it before.