Results of A Battery Estimate Experiment on 15" 667 & 800 MHz

[Jerry Krinock]

Here are the results of some experiments on 15" 667 and 800 MHz battery
runtime estimate experiments.

The most interesting result is that I repeated Case 2 with different amounts
of RAM installed, 256 MB up to 1 GB, and found that there was **no
difference** in the battery runtime estimate.  There is quite a bit of
"noise" in these estimates - it varies plus or minus 10 minutes with each
trial - but there was definitely no correlation with the amount of RAM
installed.

                Runtime Estimate
                 For Each Case
                ----------------  Purchase
Battery SerNum   1     2     3     Date     Usage since purchase
--------------  ----  ----  ----  --------  -----------------------------
ZZ2322DGL8VB    2:53  2:00  1:36  2002 Sep  Used half-time in 667 MHz PB
LW1406VXL8W     2:46        1:31  2002 Jan  Used half-time in 667 MHz PB
ZZ21507AL8VB    2:29        1:15  2002 May  Used full-time in 800 MHz PB

Experiment was done with three different batteries, all model number M8511
(667 MHz and 800 MHz generation).  All batteries have been "calibrated";
that is, allowed to run down until the computer went to sleep.  Each battery
was  fully charged to begin the experiement.

In each case, I installed the battery, pulled the power cord and allowed the
battery estimate to stabilize for 2 minutes, then read the "Time Remaining"
Runtime Estimate.

Case 1.  667 MHz 15-inch Powerbook G4 with 512 MB RAM, 30 GB HD, Display
1152 x 768, Brightness Maximum, running only Finder with no windows open.
Fan off, Airport installed but off.

Case 2. Same as Case 1 except a different Powerbook: 800 MHz 15-inch with 40
GB HD, Display 1280 x 854.

Case 3. Same 800 MHz Powerbook as Case 2, except running FInder with 4
windows in the background, LaunchBar, CopyPaste,  Entourage, Word with 3
documents open, QuicKeys X, Synchronize Pro! X and Internet Explorer.
Entourage was in front, all other applications idle.  Fan was off.

-- 
Jerry Krinock
San Jose, CA   USA

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