From: ppicot@irus.rri.uwo.ca (Paul Picot)
Subject: Re: Sharp Palmtops???
Organization: University of Western Ontario, London
Date: Mon, 11 Jan 1993 16:23:19 GMT


dale@mkseast.uucp (Dale Gass) writes:
>fbap2018@nusunix1.nus.sg (EE POH KHIAM LINCOLN) writes:
>>Unfortunately, in high power mode AND using the serial port will
>>drain the batteries like crazy (2 hrs?). Using the AC adapter helps
>>but to my dismay, the batteries will ALSO run down albeit slower.
>>
>>Perhaps my hardware is faulty. Anyone with similar experiences?

I have found new Duracells will last an honest 4-5 hours on high power mode,
(some at 5 MHz) and a week of heavy use in low-power mode (say 2-4 hrs/day).
(This is running them down to the "Replace Main Batteries" message.

>
>I find the serial port does drain batteries much quicker, but with the AC
>adapter, I've experienced no noticable battery drain with extensive serial
>port usage.

Thanks for your other tips, Dale.

For everyone's information, here are some measurements I made on my PC-3100:

Power Usage Summary:
Running off batteries:
Low battery signal comes on about 3.2 V (New batteries are about 4.8 V)
Continuous drain while OFF: 1.3 mA  (must be that psuedo-static ram)
Standby (No program running, no keys pressed, but display on):
  55 mA with popup, 58 mA with filem, 51 mA with DOS prompt.
  All independent of clock speed.
Running, or key held down:
  10 MHz: 220 mA, 3 MHz: 118 mA, 1 MHz: 86 mA
Fast typing: (50 wpm or so)
  10 MHz: 120 mA, 3 MHz: 100 mA, 1 MHz: 86 mA, (but unusable: editor too slow)
Running Laplink:
  10 MHz: 330 mA, 5 MHz: 227 mA, 1 MHz: 150 mA
Low power mode disabled:
  10 MHz: 285 mA, 3 MHz: 180 mA, 1 MHz: 145 mA

Horowitz & Hill (The Art of Electronics, 2nd ed. - Great book! Buy It!)
page 923 says that 'AA' alkalines are 1400 mAh @ 10 mA, 1000 mAh @ 100 mA.

(I expect LithEons will perform very well in this application -- too bad
they are still 2x the price/kWh compared to Duracells)

On AC power: At 6.0 volts input
Aux power kick in/out occurs at 5.0 volts (hysteresis is about 0.1V?)
OFF: 4.8  mA
Standby:
  41 mA with popup, independent of clock speed
Running Laplink:
  10 MHz: 200 mA, 5 MHz: 140 mA

With the AC adapter plugged in, there is ZERO drain from the betteries.
(OK, less than I can measure, which is 1 microamp)
The adapter can be plugged in with the power on - the automatic switchover
is pretty robust.  The AC power can even fail, and the machine will switch
over to batteries automatically.  This might not be considered a feature,
though.  I plugged my AC adapter in to the computer once, but forgot to
plug it into the wall.  After about 4 hours of *heavy* use, (low power
mode disabled, compiling code, and lots of serial port use), the batteries
were dead.  Annoying.


On an unrelated topic:
Does anybody know what is that button on the back/bottom by the battery
compartment for?  It doesn't seem to be electrical in nature - you can
pull it out of the slot it is in. An expansion chassis hardpoint perhaps?

Finally, since this message will be going to 'world', I'll repeat my my
request for information:

I would like to hear from other users of this machine.  Have you any
tips/tricks/favorite utils?  Does anyone know anything about BIOS calls?
(particularly for power managment stuff).  I'll be happy to share all
I learn.


Paul Picot    ppicot@irus.rri.uwo.ca