Article: 9312 of comp.sys.laptops Path: uwm.edu!spool.mu.edu!hri.com!noc.near.net!news.bbn.com!bbn.com!sher From: sher@bbn.com (Lawrence D. Sher) Newsgroups: comp.sys.laptops Subject: Re: T1000SE battery life Message-ID: Date: 24 Feb 93 13:18:02 GMT References: <1993Feb23.201949.858@nas.nasa.gov> Organization: Bolt Beranek and Newman Inc., Cambridge MA Lines: 66 NNTP-Posting-Host: bbn.com In article <1993Feb23.201949.858@nas.nasa.gov> proett@tailspin.nas.nasa.gov (Tom Proett) writes: >Hi, > >I have a T1000SE which has a problem with the battery. It will only >work when it is plugged in now. If I try to unplug it, it will >shut down right away. I took the battery out and hooked it to a >flashlight bulb to drain it. It lighted the bulb brightly for >just under 6 hours. I charged it again and it still would not work. > >Is there a setting on the computer itself which tells it to not shut >down? It seems that the battery is at least fairly good if it can >light a light for more than 5 hours. > >Thanks. > >-- >proett@tailspin.nas.nasa.gov >NASA Ames Research Center This seems to be a common problem. I don't know any definitive answers, but since I faced the same problem, I had occasion to look into it. 1. Buy replacement cells, open the pack, and put in the new cells. A good source for replacement cells (in New England): Gates Energy Products, Inc. 1 Prestige Drive, Meriden, CT 06450-7105 Tel: (203) 238 6912, FAX (203) 238 6887 Voice Mail: (904) 462 8725. Attention: David Childs, sales engineer, Northern Sales Region. He was very helpful for me. The cells to get: GLF-1700A Ultramax NiCad. (The cell size, officially, is 4/3A.) Cell cost is around $5.50-6.00 as I recall. Opening the pack requires a careful dissection along the ultrasonically welded perimeter seam, visible with the pack upside down. You can put it back together again with glue of various flavors. Be sure to put back the temperature sensor that is nestled in between two of the cells. 2. Exhume the existing cell(s). Once the pack was open, I found one cell that was weak (discharged quickly) and one that was zero volts, zero ohms. (Even so, of course, the remaining cells would easily run most flashlight bulbs.) Taking a cue from various other posters ("put a good cell in parallel with the bad one", "discharge a capacitor into the bad cell") and feeling I had little to lose, I decided that if a little was good, more would be better. So I connected a 12v automobile battery charger across each bad cell (one at a time). I set the current level to "trickle", connected positive-to-positive, negative-to-negative, and turned on the power for about 3 seconds. Scarey! Longer connections obvious raise the ante, like inadvertent explosions. An ammeter (on the charger) showed currents exceeding 10 amperes, tending to decay over a few seconds to less than 10 amperes, but I wasn't about to get too academic about this. A voltmeter showed 0 volts before the treatment and 1.2+ after. I repeated this treatment about 3 times, with a respectful interval in between, like a minute. Voila, the cell now looked normal, with an open circuit voltage of about 1.3. I put everything back together, let the Toshiba charger care for the pack overnight, and the next morning, it all seemed to run fine. Note: I first tried this treatment across several cells in series, only one of which was bad. It did not help! I can hardly guarantee the safety or long-term consequences of this procedure. But, clearly, there is some rationale to the talk that a sufficient goosing of these cells can exhume them. .---------------------------------------------------------------- /Internet email: sher@bbn.com Larry Sher < US Mail: BBN, MS 6/5A, 10 Moulton St., Cambridge, MA 02138 \ Telephone: (617) 873 3426 FAX: (617) 873 3776 `----------------------------------------------------------------