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Subject: Re: Pause vs power cycle break-even point - 83.5 seconds
From: Sharon (sharon25_at_cox.net)
Date: 2003-08-22


Well, that was doggone scientific and clear! So the pause is less
power consuming for 1.5 minutes or less, but for my 5- and 10-minute
breaks turning it off is better.

Is there any more or less "wear" on the unit itself caused by turning
it off and on once each hour? The work I do requires us to work fast
and hard, so for ergonomic reasons we get a 5-minute break one hour
and then a 10-minute break the next hour, which is why I asked this
question originally. For battery conservation, turning it off is
better. How about for hard drive life extension? Is that a factor at
all? It's cheaper to buy more batteries than to replace the Jukebox!

Sure are a lot of very smart people on this board....thankfully for me!

Sharon

>(The following should be even less for the new RomBox.)
>
>http://rockbox.haxx.se/docs/battery-faq.html:
>
>12. I often need to stop my player for about 15 minutes or so, and
>when I do it runs off it's batteries. I was wondering, which is best:
>shutting the player down completely and rebooting it when I want to
>listen again, or leaving the unit on? Which way does it draw more
>power?
>
>In our testing we found the following results:
>
> HDD off, backlight off, idle 94 mA
> HDD off, backlight off, play 97 mA
> HDD off, backlight on, idle 129 mA
> HDD off, backlight on, play 131 mA
> HDD on, backlight on, play 230 mA
> HD on, reading, backlight off ~ 600 mA
> HD spin up before read max 800 mA
>
>Using the power draw measurements shown above, lets look at the
>numbers: Power-down and restart vs. paused for 15 minutes.:
>
>Pause for 15 minutes will draw: 94 mA / 60 minutes * 15 minutes = 23.5
>mAh.
>
>Power-down and restart will draw about (800mA / 3600 seconds * 3
>seconds = 0.6666 mAh) + (600 mA / 3600 seconds * 6 seconds = 1.0 mAh)
>+ (230 mA / 3600 seconds * 8 seconds = 0.5111 mAh) = 2.18 mAh total
>used.
>
>Thus, leaving it paused for 15 minutes draws more power (23.5 mAh)
>than turning off and then on again (2.18 mAh).
>
>So where is the break-even point?
>
>Each second of pause will draw about 94 mAh / 3600 seconds = 26 ľAh.
>
>2.18 mAh / 26 ľAh = 2180 ľAh / 26 ľAh = 83.5 seconds
>
>Thus a shutdown and restart uses as much power as 83.5 seconds of
>pause.
>
>--
>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



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