Extend Battery Life on ACER A500 ***ROOT REQUIRED***

[mapaz04]

Alright, for those who have the ACER A500 WIFI ONLY TAB you know that there is no PHONE on the TAB... So read on if you are interested in prolonging your battery life... jejeje

THIS HAS BEEN REPORTED TO PROLONG YOUR BATTERY LIFE ALMOST 12 EXTRA HOURS... I'M STILL TESTING... Working GREAT so far... Here are my current findings...

BEFORE CHANGING/DELETING FILES...
IDLE - 2mA
PEAK - 151mA (During stress test that ran at least 6 minutes)


AFTER DELETING/CHANGING FILE NAMES...
IDLE - 1-2mA
PEAK - 104mA (During stress test that ran at least 8 minutes)

You need ROOT to do this (See my post on how to ROOT the tab... jejeje)and must have a ROOT enabled file browser to make the changes...

1.) Find/Locate the directory /system/app and find the PHONE.APK and the TELEPHONY.APK

You can either rename the files (e.g. PHONE.OLD and TELEPHONY.OLD) or even DELETE the files.

DONT FORGET TO MAKE A BACKUP OF YOUR FILES BEFORE DOING ANYTHING!!!

***IF YOU NEED TO FACTORY RESET YOU WILL HAVE TO REPLACE/RESTORE THESE FILES OR YOU WILL BE STUCK AT THE START SCREEN!!! I am not responsible if you brick your device!!! ***


For those that do not follow advice and deleted the files before making a backup, I have attached both files on this thread...

[schettj]

Can you actually test this with the batterymonitor widget (free from the app store)

You just need to measure for a day or two with or without the change to see if it has anything more than a placebo effect. On some devices, it has no actual measurable impact on battery load/runtimes.

[PropagandaX]

I might try this out once we get bootloaders and custom roms. That way if I bork it I can flash a new rom and be back in action. Thanks!

[mapaz04]

Ive restored my files and will have the tablet back to factory. Will only install root (if needed again), root file explorer, screenshot ER (for posting the screenshots),and the batterymonitor widget. Im going to leave the tablet running alone from 8am-8pm and post screenshot. then the next day I will be doing thesame with the files changed.

I am only resetting the tablet to be fair as I run many widgets and applications, this will give us the best test in my opinion. jejeje.

Will get back to you guys soon!!! jejeje

EDIT 1: HAHA! When I chose to do the factory reset I freaked out for a second... It booted into a RECOVERY KERNEL... I thought I had messed up and didnt restore the files correctly... Waiting... jejeje...

EDIT 2: SUCCESS!!! Back to Android... About to do what I posted above... jejeje

[mapaz04]

Alright, here are some screenies to show the current system state...

I will update tomorrow on the status. I will leave the tablet unplugged for 12 hours and post back.

then I will do thesame with the APK's renamed. Hope this works... jejeje

[schettj]

I can't see any detail in those screenshots (you need to convert png to jpg to prevent the board from scaling them to a tiny amount.)

The number that is important is the mA being drawn. You can see this number in the log view, or on the real time widget display.

The thing you want to compare is the mA draw when idle "stock" and then "after the mod"

Unless those numbers differ by 10% or better (which is 110mA at idle, and 330 or so under load on my GTablet, so 11 and 33 difference) then you've not really saved a statistically significant amount of power.

For that, you don't need to run a test for a whole day. Up the sampling and reporting rate on batterymonitor widget to 1 minute. With the old system, turn on the tablet, and leave it on unplugged for 5 minutes. Then run benchmarks on it for 5 minutes (or do the setcpu stress test for 5 minutes)

Look at your log in battery monitor. Record the average idle draw (should be in the low 100s) and the under load draw (should be over 300)

Repeat the test after doing your modification.

Post all four numbers here. I can tell you exactly how much more battery life (if any) you will get with your mods

[mapaz04]

Alright, Ive done as asked... Here is the results...

STOCK -
IDLE - 4mA
Peak Stress Test - 77mA

CUSTOM
IDLE - 2mA
Peak Stress Test - 16mA

***NOTE: The first time I ran the stress test under the CUSTOM way, it reported a peak of 150mA but the test ran waaayy too fast compared to the STOCK test so I rebooted the Tablet and this was the test after reboot.***

You be the judge of weather or not it lowers battery consumption. I think we need more than one tablet to test this 100%. I have restored my tablet to factory and tried this... Anyone else care to give it a shot? Due to the difference in testing speed I dont want to make full assumptions but it does look like its working people. Please let me know if it works for you!!! jejeje

[schettj]

Originally Posted by mapaz04

Alright, Ive done as asked... Here is the results...

STOCK -
IDLE - 4mA
Peak Stress Test - 77mA

CUSTOM
IDLE - 2mA
Peak Stress Test - 16mA

***NOTE: The first time I ran the stress test under the CUSTOM way, it reported a peak of 150mA but the test ran waaayy too fast compared to the STOCK test so I rebooted the Tablet and this was the test after reboot.***

You be the judge of weather or not it lowers battery consumption. I think we need more than one tablet to test this 100%. I have restored my tablet to factory and tried this... Anyone else care to give it a shot? Due to the difference in testing speed I dont want to make full assumptions but it does look like its working people. Please let me know if it works for you!!! jejeje

Er... SetCPU/Info...

Tap Stress Test.

It will run UNTIL you hit the back button. It never stops. So, there's your problem. You actually want it to run full out for 5 minutes, then press the back button to stop it. For me, that pumps my 1.4Ghz overclocked tegra2 to 100% on both cores, and draws 515mA. You'll only see that if you let it run for 5 minutes, and only if you've changed the reporting/monitoring times in batterywatcher to 60 seconds.

For the idle test, set your screen timeout for more than 5 minutes. WE DON'T want the screen to turn off. We just want to let it sit for 5 minutes, ON, not in deep sleep, which doesn't measure anything at all.

The result of your test is... the idle number is bogus, unfortunately, as is the peak. So, you need to try again. 2mA isn't enough to power the ram chips, let alone a cpu, lcd, and a digitizer. 16mA might keep your ram alive.

So, my guess is either you ran the tests wrong (which sure seems likely) or your device isn't remotely reporting current draw correctly.

Just to assure you there is no way in hell those numbers are possible, Acer lists the battery at 3260mAh, and they list video playback runtime at 8 hours. Or, 407.5mA draw during video playback.

I would expect your "under load" numbers to be well above what you reported. By 3X, or in the case of the 16, 30X.

So, I guess you'll have to go on "gut feel" for this hack. All it's doing is potentially reducing CPU load, there is no hardware associated with the phone apks. Furthermore, since this hack was based on noting that the phone stack hurt Froyo roms, and this is a "for tablet" Honeycomb OS, its extremely doubtful it has any effect at all.

It has no measurable effect on gingerbread roms running on G-Tablets (also tegra-2 dual core, but with half as much ram), but a slight (5%, which imho is below the noise threshold) improvement on stock Froyo roms on the Gtab.

[mapaz04]

dActually, my screen settings had it dimming out... by the time the second dim went out and I tapped the screen, the test would stop... never hit the back button though so maybe its at screen tap? or something...

I will try without the screen timeout... I had not thought about why it stopped as I thougt it was a test that would take some time and then end on its own... jejeje

I will try again and post tomorrow... No probs though, so far, I hope it improves battery but the battery is pretty damn powerful as is and handles lots of use before requiring a re-charge...

I will post the new information soon. Thanks for the help, I am still quite optimistic on this thought... to me, logically, it makes sense... jejeje

EDIT 1: BTW... you said that the IDLE and the PEAK are bogus? Hope you are talking about the software because, as you can see on the attached screenshot... ITS SHOWING 1mA so... Just making sure you know im not LYING but reporting what YOU told me to use... And this screenshot is changed to JPEG... Also find the LOGS from when I REPORTED THE INFORMATION... jejeje... Glad its documented... dont you??? jejeje

EDIT 2: And if you see the logs... PEAK ANYWHERE ON THE LOG IS 150mA... Check it yourself, I have attached the screenshot as a compressed file too so you can zoom into the numbers if needed... jejeje

[mapaz04]

Alright, I hope this test clears all doubts... First of all, I would like to state that I found the BATTERY INFO to have 1200mAh as opposed to the 3260mAh you posted... I have changed that... I have also cleared the log since the previous information was "wrong"... here is the information I get...

BEFORE CHANGE...
IDLE - 2mA
PEAK - 151mA (During stress test that ran at least 6 minutes)

AFTER FILE NAME CHANGE...
IDLE - 1-2mA
PEAK - 104mA (During stress test that ran at least 8 minutes)

Conclusion...
If what was stated before is correct and what we need is at least 15% difference in numbers... would 48mA not be over that amount? Just my 2 cents...

BUT... I GET WHAT YOU ARE SAYING... MAYBE THE APP IS REPORTING WRONG OR I AM RUNNING SOMETHING WRONG... I have not used batterymonitor before so... These are my results... There you go. jejeje