Path: utzoo!attcan!telly!robohack!hybrid!torsqnt!nixtdc!tracy From: tracy@nixtdc.uucp (Tracy Tims) Newsgroups: comp.sys.laptops Subject: Re: T1000SE Recharging Times !? Message-ID: <1990Jun12.145839.29205@nixtdc.uucp> Date: 12 Jun 90 14:58:39 GMT References: Organization: Nixdorf Computer Engineering Company Lines: 47 In danher@lan.informatik.tu-muenchen.dbp.de (Daniel Hernandez) writes: >My T1000SE's charging light always turns to green after at most two >and a half hours even though the manual and several reviews say it >should take approx. four hours! >... Are the batteries fully >charged after 2,5 h (which would be great -- my usage pattern is too >irregular to be able to tell from the resulting operating times...)? I spent some time testing the charging on my T1000SE. It charges the batteries fully in 2.5 hours. After such a charge, I get a little over 2 hours with the backlight up full, and 3.25 hours with the backlight down all the way. My conclusion is that the battery is charged fully. There are a couple of interesting things about the battery management on the T1000SE. The behaviour and the documentation don't quite match. As far as I can tell, the only circumstance under which the battery is NOT being charged is when the green light is ON (or when the external power is disconnected!) Secondly, the unit doesn't detect full charge condition as well when it is being slow-charged (that is, when you have the computer turned on). The green light will be out, but the battery will still be charged. In this circumstance it is possible to overcharge your battery. If you have your computer plugged in, turned on, and the green light is out, check to see if your battery is getting warm. If it is, turn the machine off, pop the battery off for a second or two, then replace the battery, turn the machine back on, and use the alt-esc control panel to tell the machine that the battery is fully charged. This will turn the green light on, turn the charging off, and you can continue to use the machine without worrying about it overcharging. (The battery starts to get warm because it has stopped storing electrical energy and has started to convert it to heat.) I tend to use this technique to make sure I fully discharge the battery (without little chargings) every so often. In fast charge mode the battery does not get warm until the very end of the charge cycle, and the rise in voltage on the charged battery is detected quickly (I assume this is because of the much higher charge current) so there is nothing to worry about. When I got mine I spent some time with an ammeter figuring out how its charging system behaved. Apparently the batteries can be charged even faster than the computer is capable of charging them. One of these days I am going to take a cheap Houseworks 7.2 volt, Makita-compatible battery charger and modify it to fast charge the T1000SE batteries. It shouldn't cost more than 30 dollars. Tracy Tims Nixdorf Computer Engineering/Sietec/Nixdorf/Siemens/Siemens-Nixdorf, etc Toronto, Canada (416) 496-8510