Why does my battery drain whilst travelling and my roaming is switched off?

Have you tried just turning cellular data off ("Settings -> General -> Network"). You may be right, it is just the celluar radio constantly turning on trying to connect. Turning cellular data off should turn the cellular radio completely off, so regardless of those other settings you mention, only wifi will even be available for a data stream.

I've got the same problem, both in Singapore and Spain. My home country is the Netherlands. I found out, it only happens abroad when data roaming is turned off and I create or update something on the iPhone which normally would be synced. E.g. new calendar entry, update details on a contact. Somehow the phone still tries to sync the update, although data roaming is turned off.

The usage stats can be used to identify this problem. Even when the phone is in standby, the usage time still increases, together with the standby time. (See Settings; General; Usage). Also, when using the phone, the standby time increases, so usage and standby increase at the same pace.

Looks like a process in the background continues trying to sync the update in the calendar or contacts list, even when on standby. This drains the battery. Even restarting the iPhone does not help.

How to (temporarely) solve this: I've been able to stop this by enabling data roaming when the problem occurred. But of course, there are costs involved. Another option is to connect to a wifi network and let the phone sync the changes.

Hopefully Apple provides a fix for this quickly.

iPhone 4

iOS: 4.3.3

I've experienced the exact same thing.

iphones when you click the "off" button don't turn off they are suspented if you really want it to turn off you have to hold home and then hold "off" unless it give you the turn off slider and then slide it

and also li-ion batts will loose power even if 100% off over time

I had this problem over the weekend. It's very annoying.

Anyway, I read your posts and some others and the only thing that's changed on my phone since I was last abroad and didn't have this problem is that I enabled MobileMe to track the location of my phone.

Makes sense.

The app is constantly trying to update apple with the whereabouts of the phone. With data roaming turned off, it can't do it, so tries and tries again and the phone never gets into standby. Make a wifi connection and it's fine for a few hours as it can update the location, but next time it tries if you're off the wifi it'll frantically try again.

This also explains why it doesn't have the problem if data roaming is left on, as it can carry on reporting location as usual (at your expense).

Also, because you configure it in the mail account settings, that explains why you get the message about data roaming being turned off every time you look at your messages.

Try removing the MobileMe account from your phone - you'll see the battery drain goes back to normal.

Apple should fix this bug - they just need to change the app so it checks whether data roaming is turned on or not before updating location. Maybe a message saying MobileMe needs data roaming turned on to work abroad, or maybe it could just check if it's enabled and if not, don't try to make the connection until the phone is no longer roaming. The problem is if your phone is stolen and goes abroad, without MobileMe doing what it's supposed to be doing your data is compromised and you won't have the cool remote erasing functionality etc.

Oh well!

I agree with MennoK and Dotmit, I had these exact symptoms whilst roaming in Hong Kong this week. Updated a contact then battery usage went up to about 20% per hour.

In future will remember to turn on WiFi occasionally.

iPhone 3GS and iOS 4.3.4

Phenriques, I found deactivating everything didn't help. I put the phone in Airplane mode (which should kill all the radios etc.) and it still drained battery and ran hot. So make sure you don't update anything in your phone that will cause it to try and synch with a server: contacts, calendar entries etc. If you do update something, then I suggest you find a Starbucks or other free wi-fi and let the synch complete. I found as soon as I returned to my home network and re-enabled 3G data the problem went away - presumably because the contact was able to synch.

Guys, the only thing you need to turn off is MobileMe in the mail accounts settings - once that tries to stop synchronising, the battery drain goes away too.

It's because Apple have written it badly and it tries to sync all the time with or without a data connection, so the phone never really goes into standby.

I've just found this thread after researching why my iPhone 3GS battery started to drain while I'm on vacation in Spain (normally UK). As per this thread, the phone was also running very hot and felt like it was burning a hole in my leg. The battery was draining so fast that I could watch the %age battery tick down! It got through about 50% charge in just under 1hr, almost 1% per minute.

This thread helped me fix the insane battery drain as I recalled making a small change to a contact that turns out to be linked to my Google account during the day. I had turned all phone features off to preserve battery and not incur excessive roaming charages so I guess the iPhone was burning out attempting to sync but couldn't as data/roaming data was disabled.

After reading this thread, I enabled everything for a short while to enable the iPhone to sync and the battery drain has returned to normal.

It's insane that a bug like this exists through multiple iOS revisions and it doesn't help that the fix is couter-intuitive (turn everything on when the battery is draining massively).

Thanks to the posters on this thread. 😀

My Battery issue was solved yesterday by doing what frendo is explaining, yesterday at 18:00 was at 95% and today at 17:00 is at 64%, almost 24 hours, I did it only a few calls. It is not bad for a iPhone.

The procedure is:

go into settings - Mail Contacts Calendar - choose the account and switch off Mail, Contacts and Calendar. I then wait 5 mins whilst the data is removed. Then switch it back on.

I also took care of time to time clossing the apps by clicking twice in the home button, and then close them.

It may not be a bug in iOS... but you can control what your iPhone does with processes by making sure that the Springboard (that is, the iOS's home screen) is the current app. This forces other processes to be suspended, so it should avoid your iPhone from getting hot due to excessive CPU usage.

Hope this helps for the next time you travel!

--tonza

I wish you guys would stop replying with information that won't help.

I already posted the solution. It's not a bug in the OS. It's because MobileMe is badly written.

If you turn off MobileMe sync while data roaming (with data roaming off) the battery use and CPU heat goes back to normal.

What do I have to do to get this answer marked as correct? :p