I have been running Jelly Belly since it was first posted. Have ver 3.6 on it now. Have been running the kernel that comes with the JB Install. Earlier this week I decided to try a new kernel. Each time I flashed a kernel my battery life got worse. Last one was Francos 180 something 384. I expected battery life to improve but it got worse. Tried tweaking the settings but nothing improved it...ultimately it got worse.
I will admitt that I have a bad habbit of dirty flashing my roms, but the first version of JB I did wipe everything. Just didn't wipe after the updates as they rolled out. But nothing bad ever happened until I flashed the first kernel...I think it was the stock linero version.
I was down to getting three hours on a full battery yesterday. That was very light use. It was just burning up battery just sitting in my pocket.
So this morning I did a Titanium backup update to be sure I had all my apps and settings data, did a complete wipe, reinstalled the JB ROM, reinstalled franco kernel, re wiped, installed Titanium update.zip, wiped everythign again, rebooted and restroed my titanium backup. My battery life is amazing again.
I have read over and over that there is no reason to wipe when flashing a kernel. From now on I will wipe every time I do a kernel. I will continue to dirty flash ROM updates.