Issues with Ultrabay battery - does your T60 destroy them?
Posted: Sun Apr 15, 2007 8:20 pm
I have a T60 that I use on battery power almost every day with a combination of the six-cell Li-Ion main and the Li-poly ultrabay batteries. The latter of these two has caused nothing but problems for me, and I think Lenovo's poor battery management strategy is to blame.
The basic problem is that, when discharging, the laptop will completely drain the Li-poly battery to zero before starting to drain the main Li-ion. This means that, in the course of your normal day's computing, you'll fully drain the poly battery every single time - even if you only use half the capacity of the two batteries combined.
I don't know if this kind of deep discharge / full recharge cycle is damaging to Li-poly cells in general, but my experience certainly seems to suggest it. After my first battery was reduced to half its rated capacity in just a few dozen cycles, I called up Lenovo and got a replacement under warranty. Well, my second battery is now at 54% of its original rated capacity after about four months and 65 cycles. That means that, under typical usage, it's now good for a whole 45 minutes.
Further suggesting that Lenovo's design is to blame: Dell Latitude notebooks will discharge the li-poly secondary to 10%, then switch to the primary. They drain the li-poly to zero only when the primary drops to 10%. The D610 that I used to own was at ~85% of its original capacity after eight straight months of daily use.
Are there any T60 owners with ultrabay batteries and similar experiences? Or opposite ones, for that matter? Have I uncovered a flaw in the design of these machines, or am I just the recipient of two bad batteries?
Note: the batteries are never subjected to more than room temperature - the issue is not thermal damage.
The basic problem is that, when discharging, the laptop will completely drain the Li-poly battery to zero before starting to drain the main Li-ion. This means that, in the course of your normal day's computing, you'll fully drain the poly battery every single time - even if you only use half the capacity of the two batteries combined.
I don't know if this kind of deep discharge / full recharge cycle is damaging to Li-poly cells in general, but my experience certainly seems to suggest it. After my first battery was reduced to half its rated capacity in just a few dozen cycles, I called up Lenovo and got a replacement under warranty. Well, my second battery is now at 54% of its original rated capacity after about four months and 65 cycles. That means that, under typical usage, it's now good for a whole 45 minutes.
Further suggesting that Lenovo's design is to blame: Dell Latitude notebooks will discharge the li-poly secondary to 10%, then switch to the primary. They drain the li-poly to zero only when the primary drops to 10%. The D610 that I used to own was at ~85% of its original capacity after eight straight months of daily use.
Are there any T60 owners with ultrabay batteries and similar experiences? Or opposite ones, for that matter? Have I uncovered a flaw in the design of these machines, or am I just the recipient of two bad batteries?
Note: the batteries are never subjected to more than room temperature - the issue is not thermal damage.