On Mon, 05 Apr 2010 21:27:12 -0400 Lewis G Rosenthal wrote:

Lewis:

Following up on my query:

  

A good link for you:

http://batteryuniversity.com/parttwo-34.htm
    

Thanks for the link, some good advise there that I was unaware of.

  

By booting into XP I find that it is detected as a dead battery.  I also discovered that there      

is a  

power option app that allows the user to perform maintenance tasks on the battery to help it maintain a longer life.        

  

While there are only a handful of manufacturers of the various cells (Sanyo, SONY, Panasonic, Hitachi?, and a couple more which escape me, now), the electronics in the battery are really the only difference between the branded ones and the aftermarket ones, AFAIK.

    

As a followup, I purchased a battery online from a 3rd party dealer.  It's a Sanyo, as was my original.  It cost about 45% less than a Lenovo battery.  And, under XP the power app (as well as thinkvantage message center) give me alarms and warning messages that my battery is not authenic.  What a PITA, I had to disabled that stuff and downloaded a 3rd party battery meter.

  

And now the power app will no longer perform "battery maintenance tasks" to help extend the life of the battery.  So your comment that "the electronics in the battery...." is more important than when I first read it.

  

So, for lurkers, if you have a T61 you may want to balance the cost savings of a 3rd party battery against the loss of Lenovo's thinkvantage battery maintenance feature.