ultrabay batteries - bad by design?

[zhenya]

Several months ago I purchased a second battery for my z60t to fit in the ultrabay slim. I quickly became aware of the fact that when running on battery, the default setting is to completely run down the ultrabay battery before switching to the main battery. I immediately realized this was probably bad news for the life of the battery, because deep discharge cycles will quickly shorten the life of a lithium ion battery. I then watched over the last few months as this battery quickly deteriorated as expected. It is now at just 64% capacity with just 30 cycles on it. I called Lenovo, and they sent out a new battery with no hassles, but I can't help think that I'm only going to see the same pattern repeated. Have others had this same problem? Is there a hidden setting somewhere I haven't come across to determine at what discharge level to move to the 2nd battery (and even better, in what order to use them, as I'd prefer it used the main battery first!)?

[Dead1nside]

I remember having an argument with one of the more established members of the board about this. He was saying how this is not a design fault and such, and I was saying it doesn't take much effort to allow customisation of which is to be discharged. It was largely a circular argument... I still think I'm right though

I have heard reported that if you eject it and pop it back in that it will discharge the main battery first. Look on thinkwiki.org under the ultrabay battery.

[christopher_wolf]

I have had my Ultrabay Slim battery since as long as I have hadmy T43 and I have yet to have any problems with it. It would be, however, nice if one could choose which battery to start discharging first. Deep cycling it can be avoided by tweaking thresholds and ejecting it when it gets near 0% charge.

[zhenya]

which thresholds would I tweak? I can set the option to warn/hibernate the computer at a certain percentage left, but that only affects the 'entire system battery' which, as the power management program sees it, is both batteries combined. It still discharges the ultrabay slim battery all the way to zero without giving any notification either. So even to pop it out before it reaches zero would require me manually checking up on it!

[nelson]

I've wondered the same thing about running the Ultrabay battery down first. Over on the T60 forum, we're having a discussion of everyone posting about how quickly their batteries start losing the ability to hold a charge. There's definitely a serious problem with them. The only good news is Lenovo seems quick with sending out replacements under warranty.

[davidspalding]

Interesting.... I hadn't thought about how fast an Ultrabay Slim battery would wear down under these circumstances. Considering the MSRP of these, one oughtn't consider them "disposable" (use and lose within 1 year)....

Checking Power Manager, my first battery* (bought 11/2005) is at 67% capacity after 157 cycles. I don't know if this is because I only recently started draining my Ultrabay batts to 0% recently, or.... This makes me want to check on the warranty again.

* I have 3 Ultrabay Slim batteries.