dan@rna.UUCP (Dan Ts'o) (01/29/91)
As promised, though a little delayed, here are measurements from my Toshiba T1000SE, which has a 2Mb memory card (Legend) and the internal modem (Megahertz, MNP-5, 2400baud). 8ma Power off current, presumably for memory maintenence and internal battery charging. 8ma Power off current, no modem. Thus the modem when powered off draw no current. 6ma Power off current, without 2Mb memory card. This component must be to maintain the remaining 1Mb and provide charging. 440ma Power on, LCD contrast low, brightness low. 450ma Power on, LCD contrast high, brightness low. Thus the contrast change makes a small, but measureable effect on current draw. 630ma Power on, LCD brightness high. A much larger effect from the LCD backlighting. If the 2Mb card is removed, there is essentially no change in these last 3 numbers (perhaps minus the 2ma). Thus the 2Mb card draws a minuscule amount during operation. 900-1030ma LCD bright, floppy spinning. 750ma LCD low, floppy spinning. +40ma modem online with carrier. -50ma modem removed. Thus the modem requires 50ma when the machine is on, and an additional 40ma (90ma total) when online. Presumably Toshiba's modem responds to the modem off control and wouldn't draw the standing 50ma. This misfeature of the Mhz modem would seem to cost 10-15 minutes of battery life. -50ma Processor in slow mode. Another savings of 10-15 minutes running in slow mode. -6ma LCD screen in inverse mode (most pixels dark), saves a tiny amount of current. -600ma The typical fast charge current into the battery. It varies considerably. Well, I hope I didn't forget anything. It would seem that you're best off disconnecting the modem, if possible, running the CPU in slow mode, using minimal backlighting and not touching the floppy. Of course, you probably already knew that. It was surprising how much difference using low LCD brightness makes. It could give an extra 30 minutes. I'd be curious how much the hard drive of a T1000XE draws. It would seem that if you can live with the 2.5Mb "hard drive" afforded by the 2Mb ram card, that your battery life should be much better. BTW, 8ma memory backup, 1700maH battery: 1700/8 = 212.5 hours = 8.85 days which is about my experience for how long my memory lasts between full charges. Cheers, Dan Ts'o 212-570-7671 Dept. Neurobiology dan@rna.rockefeller.edu Rockefeller Univ. rna!dan@nyu.edu 1230 York Ave. tso@rockvax.bitnet NY, NY 10021
faigin@aerospace.aero.org (Daniel P. Faigin) (02/02/91)
In article <1071@rna.UUCP> dan@rna.UUCP (Dan Ts'o) writes: > Well, I hope I didn't forget anything. It would seem that you're best > off disconnecting the modem, if possible, running the CPU in slow mode, using > minimal backlighting and not touching the floppy. Very interesting. The numbers should extrapolate well to the T1600. I, too, am curious about how much the hard disk draws. There should be different numbers for "spin-up" versus "steady-state". The 1600 also has screen blanking and turn-off-disk facilities when running off battery, as well as a "cpu sleep" mode. Daniel -- [W]:The Aerospace Corp. M1/055 * POB 92957 * LA, CA 90009-2957 * 213/336-8228 [Email]:faigin@aerospace.aero.org [Vmail]:213/336-5454 Box#3149 "A consensus means that everyone agrees to say collectively what no one believes individually" -- Abba Eban