Thinkpads Forum

I just got my new T61 SXGA+ laptop.

Before I start using it, any advice on the battery. Should I power on the laptop with the battery and let it drain out and then fully recharge it overnight

or

charge it full overnight before powering it up?

I'd like to maximize its battery life span.

Thank you.

Pics later.

i'd say just use it. make sure to set the battery thresholds in power manager, though. the defaults will engage the charging circuit any time the machine falls below ~95%, it think, if ac is connected. everything i've read suggests that it is frequent, deep discharges and this continual topping the battery up is what leads to early deterioration.

If you consider that a LiOn battery has a finite number of charge cycles in its life (500 to 1000 depending on who you believe) then discharging it completely for no good reason just uses up one of those lives.

There's also a setting buried in the power options to optimize for battery longevity, the computer will allow the battery to swing down further before it starts recharging it, rather than trying to keep it topped up all the time. Supposedly that will give you longer battery life overall.

sarbin wrote:everything i've read suggests that it is frequent, deep discharges and this continual topping the battery up is what leads to early deterioration.

There seems to be so much conflicting info floating about with respect to batteries, charging philosophies, and the like.

I wonder whether the "let it drop to ~75%" philosophy is valid, or is just another of those old Thinkpad wives' tales that gets bandied about.

I personally top mine off, but then again run it on AC 99.x % of the time anyway.

Is there an EE specializing in battery technology in the house?

Art

Art, part of the problem is that there ARE real differences in proprietary construction from one company to another, so that "all" LiOn or NiMh or NiCd (which is not NiCad) batteries are not the same.

Ask two engineers, you'll get three more opinions. The folks at Saft (inventors of NiCad and trademark owners) will tell you they have no "memory" problem in their cells--but some of their competitors do. Salesmanship? Or engineering?

I've got Panasonic NiMh cells that hold a good charge (maybe 75%) after six months, while unbranded Chinese ones are dead in three weeks, from internal self-discharge. Obviously, there are gross differences and with LiOn it is even worse, since some of the manufacturing problems can cause fire and explosion. Something is obviously more critical, not just different, in LiOn.

But no matter what battery you get or who you get it from--they all agree on a limited number of charge cycles. They may claim 1000 rather than 500, but no matter how you slice it, deep cycling one still eats one full charge cycle. Might as well use that "for real" rather than just for conditioning, whether it makes a difference or not.

Access Help, which is installed on your T61 (ThinkVantage Productivity Center, Access Help), says:

"For a new battery:
Fully charge the battery before using it. Use the battery until it is completely discharged.

To extend battery life:
Use the battery until it is completely discharged. Fully charge the battery before using it."

As far as i understand, the recommendation "use the battery until it is completely discharged" doesn't mean that you would have to run the notebook on battery power as long as you have access to AC. It probably only means that you should wait with charging the battery until it's completely discharged. If you use AC all the time, it could take a full year or even longer for the battery to self-discharge completely.

Use the ThinkVantage Power Manager to set the charge level thresholds accordingly. You will have to set separate charge level thresholds in every Windows user account.