I registered just to post the following:
Since I upgraded to JB, OTA (kies SUCKS and nearly bricked my phone), I can say that my battery life is much BETTER as opposed to the problem you guys are seeing.
I would suggest that it is perhaps one of your apps which is causing the battery drain - what apps are u running? what apps are causing the drain (when u check udner BATTERY setting - what is draining it?) Sometimes an old app which is not compatible with JB will cause heavy drainage.
Just thought Id share... had to wait 3 days for JB OTA, but it was well, well worth it. Loving the new OS
I am having the same issue, i think that samsung/rogers screwd up, this was a known issue from earlier on when jb rolled out for the unlocked versions, now u either root ur phone to fix the issue, or u wait for 4.2 version which god knows when will come to canada. its already out for the international version so hopefully samsung canada pushes it fast. by rooting my phone it lasts me 2 days and i do alot on it surfing the web...playing games, the screen is always on for that matter and i talk on it alot. But i think that this issue is definately UNACCEPTABLE at this point.
I agree with the posters who say the battery drain would be caused by certain apps, maybe Samsung ones, and not JB.
I've been on JB since July when I flashed my Galaxy Nexus from 4.01 to 4.1.1, using the version of Android direct from Google. My battery life improved and it has stayed fine under Android 4.2.
I had same problem of battery drain and overheating at bottom of my s3 after upgrading to JB. So I've tried many things and looked at many articles and I've found one solution that worked. It said the JB with some apps are accessing the SD card tremendously, thus overheating/drain. So I've removed the SD card and my phone is back to norm under JB. I've turned all wifi, bluetooth, gps, power saving off, brighten my screen to max, and run apps like no tomorrow and my battery last like original before JB upgrade. Try this and let me know if it works for you.
Now, I'm going to reformat my SD card and try inserting back into my s3 for test. One article said, it could be corrupted file in SD card causing this problem. So I'm going to format and leave it blank for this test.
If you think accessing CPU is causing the drain, you can monitor this by turning on "Show CPU usage" in Setting menu, developer options. This will show in top right corner, what cpu is doing and what apps are constantly exhausting the cpu.
Since the update I can get 3 days of low usage, it`s the best!
I attribute it to Juice Defender Premium, it was on sale for the holidays and it`s clearly the best!
It cuts out wifi and mobile data when the screen is off, you may also set settings for different apps who may drain your battery.
P.s. The free version offers some power saving, but not anything truly comparable to the premium version. And I cannot offer advice on the top version (forgot name)
Simple fix for the Meow,
I use the Gmail widget on my S3 and there is a big refresh buttom top right corner, when I turn my phone on and want to see e-mails I just tap to refresh. Since e-mail is text and therefore small data and it will actually load each e-mail as you open it, it`s really fast even with poor connection. I don't see where this would disadvantage a person unless 5 seconds is too long, therefore pondering on one`s level of patience might be the bigger problem.
Anyways, make sure the the e-mail app used is configured to access the internet under the JD settings menu