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Subject: Re: Extended Battery Life Testing: Good News and Bad News
From: TP Diffenbach (rockbox_at_diffenbach.org)
Date: 2003-07-30

Quoting scott <die_pokemon_die123_at_yahoo.com>:

> > > What I'd really like is to have three testers per model (FM, Recorder,
> > > Player) each of whom tests one of the given bit rates:
> > >
> > > 128 160 192
> >
> > Since you are being so exhaustive, you might also want to do something
> > really low -- say 32 or 48 -- for the audio book folks. FWIW, that one
> > should show the largest improvement.
> >
> > Michael
>
> while we're at it we should probably do a test at 320 for the true
> audiophiles.
>
> -scott

My proof of concept test was at 320. It produces (I have to cook my figures just a bit, more on that below) /about/ a 15% improvement.

The total baseline time was ~300 minutes, and the ebl time was ~330.

How cooked are my figures?
For those readers doing the math at home, that's only a 10% (half an hour) improvement.

But. The baseline test started at .1 Volts more battery than the extended battery life test. (3.8 to 3.7) As the voltage falls fairly quickly at that level, I'd guess the extra .1 Volts gave 5-10 minutes extra to the baseline:

330/290 = 13% improvement.

But. The baseline actually auto-offed itself at 209 minutes, at a rather high 2.62 Volts. Let's "penalize" the baseline at 5 minutes for this indignity:

330/285 = 16% improvement.

If we look at the data points, we discover that at 90 minutes into each test, the battery was at 3.16 volts. For the baseline, playing continued for 210 minutes (well, 119 to first auto-off). For the ebl, the playing continued 240 minutes.

240/210 = 14% improvement.

Take home message: more testing, and more data points needed.

For those who like the taste of raw data, here are the baseline:
mins Volts
0 3.8
31 3.5
60 3.3
90 3.16
120 3.05
150 2.94
180 2.83
209 Died
210 2.62
240 2.62
270 2.58
300 2.42

and extended battery life data points:
mins Volts
0 3.7
30 3.45
62 3.27
90 3.16
120 3.13
150 3.09
180 3.05
211 2.98
244 2.91
275 2.82
300 2.69
330 2.47 

-- 
Archos FM has a Rockbox!

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