Rockbox mail archive
Subject: Re: Error in Battery FAQ - Pause vs. shutdown & restart
From: Brent Geery (fasttimes_at_mochamail.com)
On Wed, 23 Apr 2003 13:59:05 +0200, Björn Stenberg <bjorn_at_haxx.se>
> Brent Geery wrote:
> > This in incorrect! mA (a measure of power) does not equal mAh (a
> > measure of energy.) Power can tell you what the player is drawing,
> > but not what it has consumed. Another way to look at it, is to equate
> > mA to the speedometer in you car, and mAh to the odometer.
> > Using the example power draw examples shown above, lets look at the
> > example given-- power-down and restart vs. paused for 15 minutes.:
> > Pause will draw 94mA / 60 minutes X 15 minutes = 23.5mAh used.
> > Power-down and restart will draw about (800mA / 3600 seconds X 3
> > seconds = 0.6666 mAh) + (600 mA /3600 seconds X 6 seconds = 1.0 mAh) +
> > (195 mA / 3600 seconds X 3 seconds = 0.1625 mAh) = 1.83 mAh total
> > used.
> > 94 mAh / 3600 seconds = 0.0261-e
> > 1.83 mAh / 0.0261-e = 70.085 seconds
> > Thus, if planning on pausing more than about 1 minute 10 seconds, a
> > shutdown and restart saves more power! I'm a little shocked, but the
> > numbers don't lie.
> I have now updated the battery faq with a calculation like the above.
> Slightly different numbers, slightly different wording, but the
> conclusion is the same.
Thanks, Björn! I'm glad I found some way to be helpful to the
BRENT - The Usenet typo king. :)
Fast Times At Ridgemont High Info http://www.FastTimesAtRidgemontHigh.org
Voted #87 - American Film Institute's Top 100 Funniest American Films
Page was last modified "Jan 10 2012" The Rockbox Crew