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Subject: real vaules: 8 MB version has 15-30% longer runtime!
From: Uwe Freese (
Date: 2003-01-24


I've now measured the battery consumption with my 8MB-modified AJB
Recorder20. The mod has much more influence on battery consumption than
I thought!

current CVS version, compiled without demos and without games, 1.726 /
7.726 MB free, measured about 600 values/s with a 10 BIT A/D on serial
port, measured one buffer cycle.

128 kbit/s, 2 MB used, avg. 131,4 mA
256 kbit/s, 2 MB used, avg. 179,2 mA
128 kbit/s, 8 MB used, avg. 113,7 mA (15,6% longer runtime)
256 kbit/s, 8 MB used, avg. 136,1 mA (31,6% longer runtime)

PS: The values are not precise absolutely. There's a factor in it that I
set manually and approximated the value my multimeter showed. But the
relative differences should be precise.

You can have a look at plots at

There's also a funny graph that shows the disk power cunsumption when
reading (note: it shows the overall current, not only the current from
the disk!):
You can see some "platforms", that seem to be the current the disk
consumes for some activity (e.g. "reading" "be spinned up").

Bye, Uwe.

Page was last modified "Jan 10 2012" The Rockbox Crew