iPhone 5 battery drops to 20% from around 40% suddenly

Hi All

I have had this problem with iOS8. Took it to Genius bar and they tested the battery. They say it's OK. They also suggested it may be a corrupt contacts file and that after restoring I should enter all my contacts manually into my iPhone. Not such a genius suggestion when I have over 1000 contacts! Anyway they were otherwise helpful. This is what I then did and it has helped a lot:

Restored the iPhone from iTunes on my Mac

Then 4 simple things to do that could make a big difference:

Turn off location services - Settings>Privacy>Locations services - (when you next start Google Maps it asks you if want to use location services - I said yes as I use this app a lot - location services are off for all other apps)

Turn off background app refresh - Settings>General

Turn off notifications - Settings>Notifications - except in my case for phone, mail, messages, messenger and Facebook - the less the better

Turn off bluetooth

These are the main ones. Big improvement in battery life. Battery percentage still sometimes jumps but less so. There are other things you can do. See below. You could try the above adjustments before doing a restore as this avoids a little work to get your phone set up as you like it.

https://www.apple.com/uk/batteries/maximizing-performance/#ios

http://ipod.about.com/od/iphone3g/tp/iphone-battery-life.htm

Finally and not least. You can save a trip to the Genius bar by installing iBackupBot. Once installed you just click on the Device>More Information and it shows you the cycle count, the initial capacity of the battery and the current capacity. Mine is about 80%. The free version of iBackupBot does make a couple of changes to the default search engine (to Yahoo) and so on but these are easy to reset

http://www.icopybot.com/itunes-backup-manager.htm

IIce had this erratic battery problem for some time. Yesterday I tried a "Hard Reset" and it's working normal now.

8. Hard reset

No matter what you do, sometimes the old rule of turning it off and on again holds true. To do a hard reset of your device, hold the home and power buttons for ten seconds until it restates.

This won’t erase any of your precious content , but it does reboot the phone and kill any potentially power-hungry background tasks.

Read more: http://www.itpro.co.uk/mobile/21859/ios-71-problems-10-ways-to-fix-battery-life- issues#ixzz3U5WGdkEj

I am testing it right now, Seems the issue is same here and my phone is at 1% now for last 45 minutes. Lets see how long it can survive.........

Started running it on 1% 3 hours ago still running, games, email check, skype vedio call, facebook browsing etc ihas been done along side continiously..................

I wasn't going to jump into this stream and say the same thing but>>>>>>>>>>>>>

Ditto for all the issues from above - battery goes from 40 to 3% in 2 minutes and when you plug it into the charger back to 40% in a couple of minutes.

Iphone 5

Just upgraded to IOS 9 and the exact same problem as IOS 8.

NO it is not my battery. My battery qualified under the Apple upgrade problem for a certain batch but of course I take it in to get it done and am told no sorry you do not get it even if your SN qualifies as your battery is OK.

NO it is not the apps I have running, messaging, location services, etc. These are limited and there is no App out there that will drop your battery 20% to 40% life in two minutes and magically bring your battery back up to over 50% in 2 minutes of charging.

I have tried every configuration even to the point is turning off all background apps.

I have turned off the 4g(LTE) and although that may increase the general battery life that does not stop the mystery drop from happening on occasion.

I can send a text message and even if that is all that is running it will drop over 20% battery capacity sometimes.

I have done every boot, hard boot and restore configuration there is and after every one I am back to the same mess.

I have seriously been considering going to the 6s but now am somewhat reticent.

same here, ios9 with 5s and goes from 20% to 3% in an instance right in front of my eyes.

The actual capacity of a battery decreases as the battery ages through an irreversible fading process. This capacity loss occurs both with active use, correlated with charging cycles, and with inactivity through self-discharge. The device may even come with substandard batteries. However, the amount of loss is linear with time and accelerates with increasing temperature. Smartphones do not typically employ sophisticated techniques for estimating the usable capacity with the basic solution basing on simple charge cycle estimation and then using an offline calibrated lookup table to find the state of charge or battery level given the charge cycle.

Battery level or State of Charge (SOC) estimation in modern smartphones cannot capture the usable capacity of the battery run time, and thus have unreliable SOC estimation. This inaccuracy manifests as sudden jumps in the battery level, and can result in unexpected shutdown of the device.

Therefore, there are two issues; (1) The battery capacity is reduced, and (ii) The device is unable to estimate the capacity loss. The detail about this can be found in the following paper.

Page on acm.org Sudden Drop in the Battery Level? Understanding Smartphone State of Charge Anomaly.

I had similar battery issues with an aftermarket battery that I had put in five months earlier. My symptoms were from no charge to incorrect & erratic percentage charge level. It turned out not to be a charger or software issue. The culprit was the "cheap" battery that I had purchased from Amazon. I just put in a $60.00 OEM battery in my phone and the problem is solved. I am happy about that.

The problem is the battery. There is a recall on certain iPhone 5. Just got off the phone with Apple customer service and they are going to replace my iphone 5 battery free of charge. Call 1-800-275-2273 to see if your phone qualifies.

The problem is the battery. There is a recall on certain iPhone 5. Just got off the phone with Apple customer service and they are going to replace my iphone 5 battery free of charge. Call 1-800-275-2273 to see if your phone qualifies.

The same has started to happen to me. Specially in the cold season. The battery life goes from 48% to suddenly 8% and sometime it turns off. When I connect it to the recharger all of the sudden the battery goes to 40% again.

Is apple going to recall their defected products or not? so many people are now having this problem and still no official answer from apple.

I have missed Steve Jobs, at least he had quality and customer service in mind for the money he was asking for iphone. The new team is all about money and no responsibility for what they give us for taking our money.

Hello sir I am using Iphone since 5 years now I have IPhone 6 I am facing problem my mobile switch off from battery 15 per but when I plugged in it's start in 1 sec even always take 1 minute and battery shows 15 per what is this problem I am facing 6 time in two days battery drains 15 percent To 7 per in sec plz sir solve this problem my phone in in waranty and i should go in apple service centre or not ??

I found out it was from using a cheap gas station iPhone charger and you right away want to get a real apple iPhone charger and now my phone drops 1% at a time instead!! I guarantee that is the issue

Same on a 6Plus...