I've been dealing with less-than-stellar battery life for a while now. I've experimented with different kernels, switched back to TouchWiz from SlimKat, analyzed wakelocks and battery stats, and Greenified everything I can think of to Greenify, all without the results I had hoped for.
Finally, I found a few posts that suggested reverting to LJC firmware (up to now I've been on MD5 bootloader + latest modem). I used mnasledov's flashable LJC zip from this thread.
I flashed the firmware and dirty-reflashed my current ROM (Dandroid). Now I have no data -- when I try to toggle it on, I get the message in the thread title. Wi-Fi works fine, and my IMEI is intact.
Should I just Odin back to stock and do a factory reset?