[AT&T Samsung Galaxy S II SGH-I777] markbc01:
Sorry you have battery life problems.

I have been running Shostock3 since it came out (it's version 3.02 today!), but I also been on and off at least five (wow can it be that many?) JB roms on my SGH-i777 (won't even mention the # GB roms here!). After trying many, I must agree with the other posters who state that this rom delivers very good battery life when compared to stock and when compared with other custom roms.

Lately, it has delivered the best battery life I have ever had on this phone using any rom (although SlimBean JB provided very very good battery life for me recently as well! Also UnNamed was great for battery life in the old GB days ;) )

I followed the recommendations made by creepyncrawly to read Entropy's (& others) battery notes/faqs. They provide some really good background, some with that typical "XDA flavor" (read technical!;). That material, plus some more plain old simple user adjustments to how and what I use on the phone have improved my phone's battery time; and it might help you as well.

It really boils down to the fact that each phone user loads different apps and our usage patterns vary.

Assume that you've flashed it and let it settle for a few days and several recharge cycles. After doing this you can see what YOUR "norms" are. They may be good or bad, but that's the baseline for you with this rom and with the apps and usage pattern you have.

(You can tweak voltage and speed (well, not speed on SS3!), but my experience has been that the more noticeable changes will be by adjusting your pattern of use, or doing the "hunt for the app" (or apps) that are burning down your run times when not in use.

Not many here seem to like or do this, but I would also try one of those "help-you-with-battery-use" apps --like juice defender (Ok, I get that many here seem to think it a waste, but it really did help me --a little-- when I used it); or get DS Battery saver (a bit more aggressive and noticeable, but you also notice the lag while you wait for things to turn on when you want them).

Actually, these may not be precision solutions, and don't focus on your specific phone app use, but they do work in a macro way to slow battery use and simply working with them for a few days or weeks will provide you with a better a sense of what the heck is going on under the plastic; they will cause you to look at what you have/run and when.

Oh, this includes using Better Battery Stats, which is fine for reporting out exactly which the apps behave --or don't-- and by how much and when. I'm not slow (well, that slow ;) but it frankly, it took me quite a while to figure out what I was reading in the BBS readouts and what they meant! (Now, after a year+ or so of using it, I don't even have it loaded, since I've done the fiddling I need --and BBS, plus those other battery apps, helped me to figure out what apps worked well, what apps I was willing to sacrifice battery on and what apps were useless and should be tossed.)

Finally, some roms just don't work for people! So it's not worth the frustration chasing something you may not be able to achieve with this or another rom. (You probably read how individuals have problems that you don't -yet, you run the same rom and the same phone! That is our world. So, too, you will read about some who make amazing claims on how long they continue on one charge. Some are pretty amazing, and some may even be real :o

My final five cents would be:

#1 run the rom a couple of days, get a baseline. Then switch from Jeboo kernel to AJK's latest for TW (I think it is 1.25ss, but I really also had great results from 1.48s) and run it a few more days. They were pretty much even for me, but others find one or the other kernel makes a real difference!). Compare after doing the same activities through a charge or two.

#2 If your battery life remains "poor," note what poor really is (ex. how much screen time? and how much total run time prior to getting to zero or 10-15%? ...something like that).

#3. Then get BBS and one of the "automatic" battery-saver programs and work with it for about 4-5 days and that many recharge cycles. See what your norms are but do it for the same type of usage!!! If better while using the battery fixers, then you can work at picking off the app or apps that are sucking your battery more than you want. Not as tedious as it sounds. Of course, staying with a rom for three weeks might be a challenge :laugh:, but this is a nice rom to work with.

#4. I don't think you will need to under-volt to get good BL. I wonder if your phone is stable in doing that? Or, does it induce additional lag? That might be a high price to pay for more run time. (You could compare the UV results with your "norm" as well!)

#5. Finally, we are on Galaxy S2 Sgh-i777 -and can change batteries all day long for not so much per battery! It is not elegant, but it works. (Done it myself several times -even with good battery life).

Good Luck!