[Poqet] power consumption

[Sven Utcke <utcke@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi,

some time ago I replaced the cells inside the batteries for my Poqet
PC Plus and Poqetpad Plus, following the advice given in
http://www.njqrp.org/poqetpc/aa2vk%20review.html.  I choose 2400mA
NiMH batteries, thereby increasing battery capacity by more than 70%.
Not bad.  While doing this, I used the opportunity of an open battery
to measure energy consumption in different states.  Well, these were
the results:

Without energy saving enabled, in A:

Program  | 16MHz | 8 MHz | 4 MHz | 2 MHz
---------+-------+-------+-------+------
DOS      | 0.53  | 0.38  | 0.31  | 0.27
VC       | 0.56  | 0.4   | 0.33  | 0.29 
JED      | 0.57  | 0.41  | 0.33  | 0.29
Toddy    | 0.59  | 0.42  | 0.34  | 0.3
Triangle | 0.6   | 0.42  | 0.35  | 0.3
TC       | 0.64  | 0.46  | 0.38  | 0.3

The same with energy saving enabled, in A:

Program  | 16MHz | 8 MHz | 4 MHz | 2 MHz
---------+-------+-------+-------+------
DOS      | 0.23  | 0.23  | 0.23  | 0.23
VC       | 0.25  | 0.25  | 0.24  | 0.24
JED      | 0.57  | 0.41  | 0.35  | 0.29
Toddy    | 0.25  | 0.25  | 0.25  | 0.25
Triangle | 0.26  | 0.26  | 0.26  | 0.26
TC       | 

Reading and writing to disk takes:

Disk    | 16MHz | 8 MHz | 4 MHz | 2 MHz
--------+-------+-------+-------+------
B: (CF) | 0.65  | 0.44  | 0.35  | 0.31
C:      | 0.52  | 0.37  | 0.31  | 0.27

The light seems to need about an additional 90mA, so isn't that bad
actually.  

The batteries are charged with 1.16A if the computer is off (so take
approximately 3 hours to charge, charging is temperature-controlled),
but only with 0.44A if the computer is turned on (and so take about 7
hours). 

If the computer is turned off, it still consumes about 2.46mA (and so
will last at most 40 days, less if we remember that the batteries also
loose some of their capacity over time).

The most interesting point on this table, at least for me, is that JED
(an emacs-clone, i.e. an editor) does _not_ benefit from energy saving
mode at all.  This is _bad_!  On my PC3100 there is a tool which makes
JED (and other programs) do trigger energy-saving mode (by inserting
additional loop-counts), but I don't know of any such program for the
Poqet.

Ok, hope this was of interest to some of you

Sven

Here are the programs I tested with:

DOS      : The DOS prompt
VC       : The Volkov Commander, a Norton Commander Clone, Shareware
           (although I use the beta-Version, which I believe to be free)
           http://www.egner-online.de/vc/en/intro.shtml 
JED      : A really good Emacs clone, which will run on many different
           platforms. Free. http://www.jedsoft.org/
Toddy    : a _far_ superior doskey replacement, which I basically use
           to emulate the behaviour of a Unix C-Shell (which I'm used
           to in real live).  Free.  Download it from
           http://www.wrotniak.net/hplx/_zip/toddy.zip 
Triangle : The test-program provided by Al Wong,
           http://www.olagrande.net/~webguy/service/poqetcom.html 
TC       : The Turbo C compiler.  This marvel is provided free of
           charge by Borland via their museum at
           http://community.borland.com/all/0,1435,museum|0|30,00.html 
-- 
 _  __                     The Cognitive Systems Group
| |/ /___  __ _ ___                                       University of Hamburg
| ' </ _ \/ _` (_-<  phone:    +49 (0)40 42883-2576      Vogt-Koelln-Strasse 30
|_|\_\___/\__, /__/  fax  :    +49 (0)40 42883-2572             D-22527 Hamburg
          |___/ http://kogs-www.informatik.uni-hamburg.de/~utcke/home.html