As I turned my phone off to board the plane to Seville last Thursday afternoon, I turned off my phone, but before that I turned off its wifi and 3g so that I wouldn’t accidentally end up data roaming and costing myself mega bucks.And I mention this because I had _exactly_ the same experience in India. Except that I actually have Wifi off on my phone whenever I'm out of the flat anyway, because there are no free Wifi points at work, and it sucks battery like a ill-thought-out metaphor.
After being at 100% charge that morning, it was already down to about 75% from being used during the day, for maybe 6 hours. I then stayed in a small village in a hostel for 4 days before heading back to Seville for a couple of days of post festival wind down.
On Monday afternoon as I got to the hotel back in Seville, I turned the wifi back on. I think I turned my phone off for one night as I slept in the previous 4 days. It still had 17% charge.
So a quarter of a day with wifi and 3g switched on takes 25% of the charge. 4 straight days (still checking/texting every so often) took about 60%.
With wifi/3g I lose 4% per hour, without I lose 0.6%. I knew it sucked power, but seriously?
I turned off the 3G on my phone before getting on the plane at Heathrow, and the phone then lasted 6 days before it needed to be charged. Which tells me that, as I continued to occasionally play games on my phone when bored, that the problem with the battery life on my phone is nothing to do with what the phone is doing (the CPU meter tells me that the phone is doing very little the majority of the time) but simply being attached to a phone mast.
What I'd love to know is whether it's really bad radio hardware/firmware that sucks up the battery, or whether having the radio on constantly triggers the phone's OS into wakefulness, interrupting it many times per second to tell it it's still there.
Original post on Dreamwidth - there are comments there.