T61P Battery Problem

Hi, I've had a T61p for just over a year. I usually use the ac adapter when I have it on, so I have 66 cycles on it. However, 2 days ago I was using it in class on battery, and after the battery drained to 90%, I plugged in a 250 GB WD portable external hard drive, and in less than a minute the battery instantaneously drops to 5%. I uninstalled the Thinkpad power manager and power management drivers, and charged it back to full. Then I tried it again. This time I let the battery go to about 60%, and when I plugged in the hard drive it did the same thing again. Does anybody have any idea what's going on with it? The Thinkvantage power manager says the the battery's condition is "good". Thanks.

 

What does the Power Manager say about the condition of the battery especially the capacity today versus the designed value?

 

I don't have it with me right now, but I believe the design capacity was 56.16 Wh? Whatever it was, the current capacity was exactly the same as the design capacity. Don't know if that is accurate. The cycle count is 66.

 

I'm interested to hear what replies you get.

I usually use my laptops plugged into AC and have found in older ones (750Cs, 760X, Sony VIAO Z-505, TP 600E, TP30) that the battery deteriorates even when not cycled much. On my most recent laptops, ( HP L2000 Special Edition, TP40) I have adopted a practice of removing the battery when it reaches full charge. It still gets used occasionally - probably several times/month - and topped up following each use. At present the battery on the HP L2000 is still good after three years of use. I recall having to replace batteries in other laptops before that age when battery life dropped too low. My ancient VIAO has insufficient capacity to carry it through all but the shortest (<1s) interruptions after years of service on AC power (with battery installed.)

best,
hank

 

The weirdest part is that the battery lasts for over 4 hours without the external hard drive. It's like if i plug it in its an instant drain.