I had great battery life with Jelly Bean. But with Kit Kat, no so great. With Jelly Bean stand by time was really great! Now, I can still make it through the day, but that's all.
If you are unhappy with the battery life under KitKat you can just reload whichever Jelly Bean firmware you were happy with - you'll find the firmware and general instructions
here - just
- boot into Fastboot mode (with the device completely off, press-and-hold Volume Down + Power)
- connect it to your computer
- download Fastboot.exe from XDA
- run "fastboot oem unlock" from a Command prompt (elevated to Administrator privilege) (this WILL wipe your device)
- then extract the contents of the firmware download and run the "flash-all.bat" file
Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM -0.001 using Tapatalk