5200 mAh - Drained in ~10h, can i get more uptime?

[Torxed]

Ok so, the short answer is probably no, and the solder-modification-config answer is hopefully yes..

I've modified the /boot/config.txt to clock down the RPi to about 50Hz which is as low as i dare to go without bumping into issues, i've also set two HDMI options but everything else is almost stock.

I've also disabled netctl and replaced it with a cron job cycling every 30 min which does a "dhcpcd eth0" in case i plug in the network cable (which i did when the battery is running low and check top for process information).


Is there any parameter i can put in the kernel line, lines in /boot/config.txt or process i can remove to increese battery life?

What my usage scenario is:
- Battery+USB cable+RPi+USB GPS
- Leave it on during the night (i was hoping for days)
- Collect data at the end of the battery charge


I heard there's some hardware you can replace on the RPi to increase battery life but i'm hoping i can do more on the software before digging deeper and potentially destroying my hardware.


Here's a top "capture":

$this->bbcode_second_pass_code('', '
top - 11:21:34 up 10:21, 1 user, load average: 0.43, 0.14, 0.08
Tasks: 63 total, 1 running, 62 sleeping, 0 stopped, 0 zombie
%Cpu(s): 1.0 us, 1.8 sy, 0.1 ni, 96.9 id, 0.2 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 213836 total, 55456 used, 158380 free, 9640 buffers
KiB Swap: 0 total, 0 used, 0 free, 20548 cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1819 root 20 0 4672 1248 916 R 58.3 0.6 0:00.83 top
1 root 20 0 4832 2688 1896 S 0.0 1.3 0:16.14 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.15 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:12.57 ksoftirqd/0
4 root 20 0 0 0 0 S 0.0 0.0 0:01.74 kworker/0:0
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
6 root 20 0 0 0 0 S 0.0 0.0 0:50.41 kworker/u:0
7 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/u:0H
8 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 cpuset
9 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 khelper
10 root 20 0 0 0 0 S 0.0 0.0 0:00.10 kdevtmpfs
11 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 netns
13 root 20 0 0 0 0 S 0.0 0.0 0:00.08 bdi-default
14 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kblockd
15 root 20 0 0 0 0 S 0.0 0.0 0:00.39 khubd
16 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 md
17 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 rpciod
18 root 20 0 0 0 0 S 0.0 0.0 0:00.21 khungtaskd
19 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kswapd0
20 root 20 0 0 0 0 S 0.0 0.0 0:00.00 fsnotify_mark
21 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 nfsiod
22 root 20 0 0 0 0 S 0.0 0.0 0:00.00 jfsIO
23 root 20 0 0 0 0 S 0.0 0.0 0:00.00 jfsCommit
24 root 20 0 0 0 0 S 0.0 0.0 0:00.00 jfsSync
25 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 xfsalloc
26 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 xfs_mru_cache
27 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 xfslogd
28 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 crypto
35 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kthrotld
36 root 1 -19 0 0 0 S 0.0 0.0 0:00.00 VCHIQ-0
37 root 1 -19 0 0 0 S 0.0 0.0 0:00.00 VCHIQr-0
38 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 VCHIQs-0
39 root 20 0 0 0 0 S 0.0 0.0 0:00.00 VCHIQka-0
40 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 cma_worker
41 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 iscsi_eh
42 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 dwc_otg
43 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 DWC Notificatio
44 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kmpathd
45 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kmpath_handlerd
47 root 20 0 0 0 0 S 0.0 0.0 5:03.02 mmcqd/0
48 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 deferwq
49 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kworker/u:2
50 root 20 0 0 0 0 S 0.0 0.0 0:01.59 jbd2/mmcblk0p5-
51 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 ext4-dio-unwrit
57 root 20 0 0 0 0 S 0.0 0.0 0:07.50 flush-179:0
64 root 20 0 87520 19672 19400 S 0.0 9.2 3:24.86 systemd-journal
76 root 20 0 9456 1256 944 S 0.0 0.6 0:04.40 systemd-udevd
99 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 bcm2708_spi.0
115 root 20 0 1692 496 444 S 0.0 0.2 1:25.20 rngd
')

That's almost the entire list, think i'm missing one or two items but i'll have to reconnect to the RPi to get a complete list.
What worries me is mmcqd, rngd and for some reason systemd-journal keeps running a lot even tho i don't touch or modify the RO filesystem.

I appreciate any help i can get :)

[grayman4hire]

Sorry, I don't have a solution or any recommendation on improving the efficiency of your setup.

Just curious on what type of battery you are using and if it is truely 5200 mah. 10 hours to me seem pretty good.

Obviously the simple solution is to get a bigger battery

[moonman]

Set journald storage to none. Though i doubt it will help.

$this->bbcode_second_pass_quote('moonman', 'S')et journald storage to none. Though i doubt it will help.

[grayman4hire]

Have you considered moving your setup to a PogoPlug E02 or V4? I wonder if the pogoplug would draw less power than a Pi.

Do you have a Kill a watt? http://www.amazon.com/P3-International- ... B00009MDBU

Might be useful for measuring if your tweaks are effective and calculating how big a battery you would need (base on the watts used).