[HD2 Android Q&A, Help & Troubleshooting and Genera] Looki75:
What can you expect from these tips?​

*Increase battery life by 3 times compared to a situation without any tip implemented!

My target is to unplug my phone at 6am in the morning and have it around 10% at 11pm. The below tips enabled me to reach this target whereas, without them, I would run out of battery at noon (same usage, of course)!

Disclaimer:

I consider that manually "swith off location" or "switch off wifi" as well as having Juice Defender on "extreme" are not acceptable. Why? Because we all need tips that enable battery savings without decreasing the user's experience! If you need to operate manually each time you want to connect and/or have 3G... this is not a solution. If Juice Defender just cut-off every communication and don't let e-mails flow, etc... this is not a solution!

However, for those who want those kind of tips, I created a special section in post 2!

Red % signification:

Well, those % in red are gut feeling of "tip contribution" to the total battery saving.

My settings which enable best battery savings without reducing user's experience!​

1. Use a NAND ROM

2% of battery improvement

Yes, compared to an SD ROM, a NAND ROM is less battery demanding. But as you can see, 2% is not a big part of the total improvement.

2. Use "SetCPU" with appropriate settings

5-10% of battery improvement

3. Lower VDD values as low as you can (till device becomes unstable)

5-10% of battery improvement

I am using Tyween settings from his ROM Typhoon.

#!/system/bin/sh
# set vdd_levels on boot by tyween (XDA Developers)

echo '245000 850' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '384000 875' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '422400 900' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '460800 925' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '499200 950' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '537600 975' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '576000 1000' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '614400 1025' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '652800 1050' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '691200 1075' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '729600 1100' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '768000 1100' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '806400 1125' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '844800 1150' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '883200 1150' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '921600 1175' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '960000 1175' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '998400 1200' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '1036800 1200' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '1075200 1225' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '1113600 1225' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '1152000 1250' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels
echo '1190400 1275' > /sys/devices/system/cpu/cpu0/cpufreq/vdd_levels

I tested even lower values, but my phone was not stable.

I read that each single piece of hardware is unique and could have its own minimum values, so your device could accept lower values (i.e. you're lucky compared to me) or on the contrary higher values (here I am luckier than you are :))

Tip "easy way to test a new set of undervolting values":

If you want to test undervolting values, themadproducer recommends to use the CONSERVATIVE CPU profile. Why? Because CONSERVATIVE seems to use the full range of scaling frequencies as it climbs up to MAX and falls back down to MIN. This way, if any particular frequency is set too low, it will complain and freeze the CPU. ONDEMAND and SMARTASS would skip over these middle frequencies or at best, never use them for more than an instant.

4. Use "Setting Profiles" for location-based WiFi

10-15% of battery improvement

This soft enables you to switch on/off wifi according to your location (based on cell towers - which does not use battery!).

Be careful:

if your location is determined by GPS (instead of cell towers) than you will use more battery through GPS than you save by switching off wifi!!!

Example:

you can define to have wifi ON when you are at home, and OFF when you leave home. Same with "work" or any other place where you know there's a wifi network to which you can connect.

Setting Profiles can also be used for automatic phone profiles switching (all kind of opitions from volumes, ringtones to screen brightness airplane mode, etc...)

However,

I recommend

you let Setting Profiles governing the wifi only. For phone profiles, I use Pocket weaver which is better I think - it can trigger profiles according to Touchdown calendar for example. Moreover, I need wifi on/off independently from hour or calendar status and these apps don't do well when it comes to integrate several conditions together.

5. Use "Phone weaver" for a night phone profile

% of battery improvement depending on situation

I am using a night profiles which goes "Air plane mode" from 11pm to 7am. But usually, I plug my phone overnight, so battery consumption is irrelevant overnight - my night profile is just to prevent radio waves to kill my brain too prematurely :) as the phone is nearby for morning alarm!

6. Properly setup your Internet apps

% of battery improvement depending on situation

Sounds obvious, but still! Do you really need your phone to check e-mails each 5 minutes? Or would 15 minutes be ok and in return get instantly a lot more of battery life?

Seriously, you need to setup your apps wisely.

e.g.: for those who use Touchdown (exchange sync), this app has awsome options: you can define "peak hours" during which you have a certain setting and the rest (off-peak hours) you will have another setting + the "push" option is very clever: it does not use much battery and on the top of the push option, you setup a period when it will go and check e-mails...

7. Use Auto brightness for your screen

10% of battery improvement

If your are running CM7, there is a function that let you set your own auto-diming values.

First you need to enable auto-dimming in Settings/Brightness and then check the box. After that, go in Settings/CyanogenMod settings/Display/Automatic backlight and set the following:

If you are not running a CM7 ROM, then just enable auto-dimming in Settings/Brightness and then check the box.

8. Use "Juice Defender Ultimate" + "Juice Plotter"

50% of battery improvement

All of the above tips are very useful. However, this one is the one tip! I came to it almost depressed by my battery life (I had all of the above tips in place already).

I did not believe this soft could really help, and I thought "ok, yeah, this app will just cut-off all communication etc... but then I will have no more auto-sync and/or push e-mail"... I thought it would be a kind of "well just don't use your phone and you will get great battery life!"...

I was wrong. This app is a must! There are all kind of options in settings. Of course the first time you have to go through it and read-read-read learn-learn-learn. But in basically 20 minutes, you are setup and you have a huge battery life improvement! I can share my own settings if anybody is interested.

And the beauty of it, is that in the huge amount of options available, Juice Defender sort out everything by itselft and as a result - I don't feel the difference

from a usage point of view

(K9 e-mail flowing, Touchdown is pushing e-mail, everything works like a clock). From a battery point of view: wow! The app says it increases my battery life by a 2.5 factor! And this is pretty much what I observe!!!

Juice plotter is also a must: it tells you how long you will last on your battery and I find it to be the most accurate app of this kind!

9. Condition / Calibrate your battery

This one is also a must – and you should do it time to time, let’s say once a month and always first thing to do after you flashed a new ROM!

By the way, if you use GPS navigation and/or Bluetooth system in your car, you must invest in a car charger – and plug the phone every time you are in your car (if not the day during which you are calibrating)… it’s another way of increasing battery life – ok, I admit, it’s more a “trick”!

10. Use small apps that help switch on/off the screen when needed

I also tested 2 small apps that actually could help battery saving on the one side, but also increase the user experience on the other side.

Screebl pro: this app is just fantastic! According to screen orientation, it senses if you are using your phone or if it is resting (lying) on the table.

Before screebl:

in order to save battery I had the screen timeout set to minimum (15sec). But each time I was reading a long e-mail, I was "playing" with the screen (up-down-up-down) in order to prevent the screen to switch-off and then unlock, etc... This was really annoying. And disturbing: I could not read an e-mail or a webpage without think: "oh, I need to play with the screen somehow or it will switch-off very soon"...

After screebl:

the screen timeout is now 5sec! (through screebl) so if the phone is resting, it switches-off more rapidly = you save more battery! And when I read an e-mail or a webpage, I just relax, concentrate on the content! Anyway, the "ON" time is the same because you had to read this e-mail anyway...

ProximityScreenOff:this is also an app to have. It switches-off the screen according to the proximity sensor status: if proximity is detected, the screen goes off. If you are left-handed as I am, you need to take care of not hiding the proximity sensor when you drag the notification bar down, but it is manageable. Not only it is easier to switch-off screen now. It is also saving battery if the phone accidentally switches-on in your pocket! We already had the lockscreen which prevent your phone doing silly things in your pocket. Now even better: in your pocked, the screen switches-off almost instantly!

There is also an option to switch screen ON when proximity is detected, but warning! this drains battery - so I don't use it! :D

And last but not least...

11. Track any bad app

% of battery improvement depending on situation

Yes, you should know about the Email.apk bug (thanks to themadproducer - I think you learn me that). And generally: you should monitor what is going-on.

I use Watchdog which will alert you as soon as an app uses CPU above a certain threshold that you set. So you know for example that a particular app eats a lot of CPu, which means battery! Watchdog also has a "white list" function for those app that you know are consuming quite a bit of CPU but that you absolutely want to keep!

Go time to time in Spare parts / Battery history / partial wake usage and see which apps are preventing your phone to sleep - they are eating your battery instead!!!

Use CurrentWidget (with log if you want) in order to track instant high current consumption but remember you have to double check with the other above tools as current might be quite high time to time, but it is a normal situation.

Edit:

I had an issue with CurrentWidget. In my case, I was logging too much and in Settings / About Phone / Battery usage, CurrentWidget was showing 12%!!! Unistalling / reinstalling might correct the issue (to be confirmed).

Use Battery Monitor Widget Pro: this will draw a graph with the battery % history in a widget, so that you can see at a glance if your battery have been decreasing with a higher rate than usual (by checking visually the slope of the curve). This also to alert you that there is something to track!

I recommend you read this thread which completely describes in a very comprehensive way how to track a battery drain!

Additional thoughts

Of course, if you are on this forum, there is a chance that you like flashing ROMs, tweak it, change settings, etc… All these activities of course use more battery than what I would call the “normal” use…

Also, some activities literally pump out the battery: games, movies, camera, camcorder, GPS navigation, bluetooth headset/earset/car system… There’s no much to do about that – just just need to be aware that they use a huge amount of battery to run; after that you make your choice: game or battery / movies or battery / do I really need the GPS navigation from work to home / etc…

Additional improvements for your phone

I strongly recommend the use of Tyween's Typhoon NAND ROM it is the most stable and complete ROM ever. I tested all of them and as soon as I flashed Typhoon, I understood it was the best... I then continued testing others, but eventually, I went back to this one!!! It is fast, reliable and updated very often! Tyween's Typhoon is here.