Why is my S3 mini battery draining so fast after switching to a foreign SIM card?

[Geelong Cat]

Hi all,

I bought an unlocked S3 mini from Amazon UK in December, and since then have been using it on the O2 network without problems. I arrived in Italy last week and decided to buy a local SIM card from the TIM network here to avoid roaming charges.

Everything works fine - calls, texts, data - except that my battery now drains at a crazy rate, from 100% to empty in about five hours, and at around 1% a minute if I'm actually using it. I was on O2 roaming for a couple of days when I first arrived, but I'm not sure whether I had the same problem then as data was turned off.

A very 'helpful' 'friend' told me that the phone was searching for a network in the UK, that there was no hope of fixing it and that I should get an iPhone instead. Is he right, at least about the phone searching for a UK network? I can't understand why that would be when all the settings are TIM. Would a factory reset help?

Thanks in advance for any suggestions!

 

[Geelong Cat]

Just to add a few more details, below is a screenshot of the battery use yesterday.



I switched the phone off overnight after fully charging it, turned it on now, and in the last fifteen minutes the battery has dropped to 89%. This is with data/Bluetooth/GPS turned off but wireless turned on.

No idea what's going on here - the phone signal would've been patchy yesterday as I was traveling, but the battery drain is so much worse than anything I've had before that I think it must be something to do with the new SIM card or roaming (which I'm not doing obviously, but maybe the phone somehow thinks I am), not just normal app usage or a bad connection.

 

[Rukbat]

Look at your mobile network signal line. Half the time the signal is weak to none, so the phone is either searching for a network or it finds a weak signal and turns the transmitter to full power to compensate (if the path from the tower is bad, the path to the tower is also bad). Evidently TIM doesn't have very good coverage where you are. Five hours on a sometimes-nonexistent signal isn't that bad. You need a carrier more local to where you are. (If you're traveling over a large area, you may need a national carrier.)

 

[Geelong Cat]

Look at your mobile network signal line. Half the time the signal is weak to none, so the phone is either searching for a network or it finds a weak signal and turns the transmitter to full power to compensate (if the path from the tower is bad, the path to the tower is also bad). Evidently TIM doesn't have very good coverage where you are. Five hours on a sometimes-nonexistent signal isn't that bad. You need a carrier more local to where you are. (If you're traveling over a large area, you may need a national carrier.)

Thanks for the response, it's appreciated.

I probably shouldn't have used that particular graph as an example of the battery drain as it's a bit anomalous - I spent the whole day on a train, hence the phone signal was extremely poor! That's not typical, and TIM generally has good network coverage. The weakness or strength of the phone signal seems to make very little difference to the length of time the battery lasts.

What is making the difference is my use of mobile data. In fact, I spent the week following my post in a very mountainous area with poor network coverage, and the battery life was virtually back to normal because I was only very rarely using the Internet. If I spend ten minutes using whatsapp, the battery charge plummets at a rate of 1% every minute or two. I'm sure this wasn't typical when I used the phone in the UK.

I downloaded the Deep Sleep app so that my phone only connects to the Internet once an hour to check for messages etc. This has stopped the battery draining when the phone's in stand-by and extended the battery life somewhat, as long as I don't use the internet too much. All the same, my phone battery never lasts till the end of the day - it's probably up to about seven hours, depending on how often I use the phone.

So yeah, I'm still at a bit of a loss! What I'd like to do is rule out the possibility this increased battery drain has anything to do with switching sim cards - if it's simply just that the phone itself has poor battery life (which it does, though never previously this poor) then I'll most likely get a new phone, as not being able to use this phone when I'm traveling is a dealbreaker. But obviously I don't want to buy a new phone only to have the same thing happen.

Thanks again.