I had the exact same locationd problem with my i6 right after jailbreak. My phone was getting warm and the cpu was stuck at about 50% never idling then I did a reboot and it went away ever since! I did however do a clean restore to 8.1.2 so I can get a feel for what stock battery life is again before I decide to jailbreak! It's so snappy compared to when it was jailbroken I'm not sure I will go back! I only had winterboard springtomize3 and a couple other tweaks but stock seems so crisp.
I've been getting about 6-8 hours usage of onscreen time on wifi with my habits of mostly surfing safari some tweetbot, Instagram, FB and email with brightness less that 50%. LTE knocks my usage down about and hour or two. If I play a demanding game like a GTA or MC5 the battery is gone in 2.5 hours easily! Very similar to my iPhone 5 on iOS 6 a couple years back!