[Samsung Infuse 4G] electricpete1:
Power Tutor has a great interface and very detailed stats available. Seems to have great credentials based on their website.

But I can only conclude we can’t trust it for our particular phone because of results above (power draw goes down as cpu speed goes up) and some other results I have seen (it seems to suggest that power used by my display does not change depending on dark/light backround, and also seems to suggest that power used by the phone does not change when I change the volume of music playing).

So, I’m looking for another way to be able to track power usage closely.

I kind of like qkster’s idea to just watch the battery go down.

I’d like to try to automate that using Tasker. I can write a program which will help me build a log of power usage.

The interface will be:

push a start icon and it prompts me to enter description of conditions that will be tested

wait some period of time (this is the constant-load test period that we're evaluating...may be listening to mp3)

push a stop icon and it prompts me for comments about anything that happened during the test.

At time of pressing the start icon, it will also record from the system:

1 - clock time (in seconds)

2 - voltage in millivolts to 4 digits of resolution (like 3784 millivolts)

3 - battery life remaining in percent to 2 digits of resolution (like 43%)

The same info will be recorded from the system upon pressing the stop icon.

All this info will be appended to a logfile and we can compute drain based on change in battery divided by change in time.

I can get these voltage and % life stats using the method suggested by Brandall’s tutorial here:

http://tasker.wikidot.com/using-linux-shell-with-tasker-for-a-technical-battery-widget

I couldn’t get the grep command to work, but I can still extract the required voltage and percent-life-remaining from the Battery sysdump using the tasker variable splitter command (I’ve already got that part programmed).

No-load voltage has a roughly known relation to battery life, but there’s also the matter of voltage drop accros the internal battery impedance that varies with load at the time of the measurement, so we don’t see no-load voltage, we see something lower which makes the whole thing somewhat variable.

Percent Remaining is the exact thing I want. But it is only given rounded to two digits, (43%). If I wanted to do a trial run listening to a 5-minute MP3 draining something like 12% per hour, the battery drop during that that 5 minutes will be only around 1%... the difference between two kernels or cpu frequency settings will be only a very small fraction of that 1%, so comparing the start and stop values which are both rounded to 1% would introduce an enormous error compared to the thing we're interested in. I can surely reduce that error by working with longer times, but that starts to become a PITA. That may end up being the only solution, but if there's any way to avoid it I'd like to be able to gather data in shorter chunks.

Which leads me to a QUESTION:

Does anyone know whether there is any way to retrieve or estimate “battery % remaining” with greater resolution that two digits (ie 43.26% instead of just 43%)?