No Low Battery Warning on iBook?

When's the last time you ran the battery down? Apple recommends doing it once a year or so for recent models
Alan Quirt wrote on :

In article vikr-AE284C.01183528112003@redacted.invalid, Vik Rubenfeld vikr@redacted.invalid wrote:

When's the last time you ran the battery down? Apple recommends doing it once a year or so for recent models to keep the time estimate calibrated.

Interesting.

The last time the battery ran down was a couple of months ago. The exact same thing happened that time -- the screen went black with no warning, even though about an hour was still supposed to be left on the battery.

This is consistent with my experience with li-ion batteries in my iBook and my Sony video camera. There is a display of time remaining which decreases at close to the expected rate, then with considerable time left the battery suddenly dies. It may indicate a fault in the batteries, but since I still get a decent lifetime out of them I don't plan to junk them.

I will try running them down deliberately a couple of times (once to caliabrate and once to see it it helped), but don't expect much change.

Tom Harrington replied on :

In article HERONaquirt-7EF70C.11515003122003@redacted.invalid, Alan Quirt HERONaquirt@redacted.invalid wrote:

In article vikr-AE284C.01183528112003@redacted.invalid, Vik Rubenfeld vikr@redacted.invalid wrote:

When's the last time you ran the battery down? Apple recommends doing it once a year or so for recent models to keep the time estimate calibrated.

Interesting.

The last time the battery ran down was a couple of months ago. The exact same thing happened that time -- the screen went black with no warning, even though about an hour was still supposed to be left on the battery.

This is consistent with my experience with li-ion batteries in my iBook and my Sony video camera. There is a display of time remaining which decreases at close to the expected rate, then with considerable time left the battery suddenly dies. It may indicate a fault in the batteries, but since I still get a decent lifetime out of them I don't plan to junk them.

I will try running them down deliberately a couple of times (once to caliabrate and once to see it it helped), but don't expect much change.

It seems when doing this, it's important to do a slow discharge. See a message by Peter Renzland in this newsgroup, under the subject of "Pismo battery depletes fast during sleep", for how to do this. I've been experimenting with his scheme on my Powerbook, and it has made a big difference in the battery capacity.