Passbook killing battery life?

Hi there,
Ever since Starbucks announced their passbook UK use, I have had EXTREME battery draining, not like a few % an hour, but drastic loss.
iPhone 4S btw.
Before Tuesday, I could let my phone run for 1 1/12 days before reaching 20%
I've now had my phone off charge since around 9am (100%) and currently have 26% (6:50pm)
I thought it was due to passbook checking my location, and so I turned it off and nothing has changed.
I'd also like to say, according to usage, It's been 10 hours of standby and 6 hours usage. But I've had lectures from 10-3 and have had it on do not disturb and barely looked at it.
Any ideas?
Thanks

sohaloh said:

I think 6-7 hours of usage is pretty normal. Standby time is always variable, but your usage time will hover around that number. I doubt passbook is doing anything to drain your battery. You might just be getting extra push notifications in the back. Disable app badges on apps you rarely use, thats also a form of push notification. Besides that just turn the percentage off it helps.

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Yeah I've done all this, the point is I haven't used my phone for that much today, sent a few messages and answered one call, it normally is around 60 or so percent by now ready for the evening, but ever since passbook it hasn't

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On that note, its lost 5% since creating this post. I haven't even touched it. That can't be right? 5% in 20 mins?!

njchris said:

One thing to rule out is GPS usage by an app. Go to settings, then privacy then location services and look for an app that has the GPS "arrow" purple (or whatever color that is)...

Are any using it while you are not in the apps?

Did you install ANYTHING else?

Is your signal bad where you are?

Did you shut down the phone and turn on again in case it's a glitch?

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I've already shut it down in hope, but nothing else installed no.
Signal has been the same since I got the 4S, haven't changed place.
But I'll check the location settings now and see whats happening

Having cancelled all passbook functions I can successfully say its not that.
Last night, having lost 90% in 5 hours I thought my phone would be dead within 10 minutes.
I had 1% battery for 2 and a half hours which included phone calls, texts and some Internet usage.
Sounds like a battery problem? Or more along the lines of the meter reading. Any fixes for this? Thanks!