Thread: Voyage frontlight battery drain measurements
View Single Post
Old 01-06-2018, 01:54 PM   #2
j.p.s
Grand Sorcerer
j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.j.p.s ought to be getting tired of karma fortunes by now.
 
Posts: 5,730
Karma: 103020299
Join Date: Apr 2011
Device: pb360
Measurement results
The /sys/class/power_supply/max77696-battery/current_now are too noisey to compare adjacent brightness levels, but current_avg looks very promising. I don't understand the large current spikes. At first I thought they are brightness level related, but they do not reliably repeat. Even longer dwells with more frequent sampling might help. The lag introduced by averaging does seem to require longer dwells at each level.

In any case, it looks like an awake idle Voyage draws a little over 40 milliampsand that frontlight current draw is proportional to brightness level 1 to 3280 (not to be confused with brightness setting 0 24). Also brightness level 0 is possible, but not from user interface. At setting 20, the Voyage frontlight is using half the power and at setting 24 it is using over twice as much as everything else.

It looks like Voyage frontlight power usage is negligable below setting 11 or so, which is reported to cut battery life in half on the Oasis 2. I plan to eventually make frontlight power measurements for the Oasis 2.
Attached Files
File Type: zip LEDma.zip (15.7 KB, 525 views)
Last edited by j.p.s; 01-06-2018 at 01:57 PM.
j.p.s is online now   Reply With Quote