ok thanks.. and yea i meant to post it into the rooting section of the forum but i didnt realize i was posting it here... do you recommend using kernel manager to flash the kernels? or do it manually?
Manually.
FWIW, I'm running the 1.8.6 Remix and get GREAT battery life. Here's the thing...
If you're using 4G LTE, all bets are off -- it's a battery hog no matter what ROM or kernel you use (at least in my experience). What I can say is that when exclusively using 3G/Wifi, 1.8.6 has been very good on power consumption for me, and I have NOT installed a different kernel. I keep mine set at 245min 1024max w/ ondemand gov (pretty standard settings) and it works great.
I generally charge my phone in the evening before bed. When I wake up, it's usually at about 90%, then I go to work, use it throughout the day, etc... by the time I plug the phone in again that evening, I'm usually still just under 50%, so yeah, I'm easily getting a full 24 hours out of a charge. Sure, there are some days when I use the phone a lot that I've got to plug in mid-day, but still, I'm not complaining.
EDIT: Don't get me wrong though, the right ROM/kernel can get you *better* 4G LTE battery life...I'm just saying 4G is going to suck a lot of power regardless of what you're running.