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Subject: Tips for extending battery life with FM recorder
From: Wayne Sherman (Wayne_at_SystemDesignWorks.com)
Date: 2003-06-17


(I apologize if this double posts, it didn't go to the right place the first
time)

Over a period of 3 days , I am recording some relatively long sessions of FM
transmitted lectures (voice only). I wish to optimize the recording process
in order to extend battery life. Here are some strategies that may help:

1) Use Rockbox instead of Archos firmware :-)
        - untested, but the FAQ claims better battery life

        Can anyone suggest specific config settings that may help?

2) Use lower sampling rate instead of CD quality 44.1 KHz.
        - less data = less DSP processing and less HD activity
        - 22.05 KHz. or even 16 KHz. should be fine for voice

3) Use MONO recording mode
        - less data = less DSP processing and less HD activity
        - lectures are mono anyway

4) Use lower bit rate MP3 encoding setting
        - smaller files = less HD activity
        - Maybe use level 3 or 4.
                According to manual
                Level 5 = 144 Kbps avg.
                Level 7 = 166 Kbps avg.

                What are average bit rates for other levels?
                 1 - ?
                 2 - ?
                 3 - ?
                 4 - ? (133-?)
                 5 - 144 Kbps
                 6 - ? (155-?)
                 7 - 166 Kbps

        Question: If I select level 5 (144 Kbps), but setup my record settings for
22Khz/mono mode, will the encoder still encode at 144Kbps average or is it
smart enough to encode at a lower bit rate? (VBR encoding should produce
smaller files automatically)

5) Upgrade hard drive with a unit that has lower spin up power requirement
and/or lower operating power consumption
        - http://www.creamofgeek.com/phpBB2/viewtopic.php?t=74

        Any suggestions on HD models?

6) Upgrade battery cells with parts that have a higher Ah rating
        - Panasonic makes some of the best quality Li-Ion batteries

http://www.mbi.panasonic.co.jp/oembatteries/english/e_ion/out_eion/defeion.h
tm

        Possible source for purchase:
                http://www.sabahoceanic.com/lithium.html
                (untried, I found them in an Inet search...USE AT YOU OWN RISK)

        Does anyone know the part#/size/form factor of the batteries?

If anyone has further suggestions or information, please share.

Thanks,

Wayne



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