I am really concerned about the health of my battery since I upgraded to ios9. Previously I used to get around 8 hoursof usage and ever since ios 9 it's gone down to about 6, 25% reduction. All the standard settings are switched off that may drain the battery and I don't understand why the same set up can be so different. In addition, since yesterday a strange thing has been happening; one minute it will be on x% and then the next drop by about 20-30% without touching it. It was on 39% just a couple of minutes ago, I did some updates and within 2 mins the "below 20%" warning came on - it was 17%, then within 2 mins its 13%. 4.5 hours from a full battery. To me, this seems like a hardware fault. Best to go to vodafone or apple store?