Hey sorry to but in but I ran across this thread and saw you where talking about kernels I'm running the ava z3 rom and I'm not using the stock one with the rom i use the preferred netarchy-toastmod-4.3.1-cfs-hav-nosbc and I get really good battery life it save me about 4 hour extra on battery but I use the internet and music alot an a few calls and alot of texts lol.
And I used to only get 5 hours or less but with I get 8/9 hours and still have 21% by the time I get home I also use the tricks on saving battery by turning off the mobile data while not using it and background data cuz I'm not downloading apps every second so I don't always need it but with doing this and downloading the kernel your good to go
hope that helps you get a better look on how it should last.
Oh forgot to say when I use setcpu I underclock to 8xx ghz and I use spear part for fast screen transition its included in the app great tool and has a few extra goodies you should check that out to ;-)
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