By mandydike, 31 July, 2015 Forum Other Apple Chat My iPhone 5 goes off at exactly 20%....i charged it till it was 29% then i switched it off for a while.. Switched it on later on and it was 32% ...please what can i do to fix my iphone 5 going off at 20% ? Options Log in or register to post comments Comments phone goes off at 20% My iPhone 5 goes off at exactly 20%...i charged it till it was 29% then i switched it off for a while....switched it back on and it qas 32%....please what can i do to fix my iPhone 5 going off @ 20% and what is the cause of it? Hi. Hi. I hate to be the bearer of bad news, but it looks like your phone's battery is on its way out. I have a 5S with a similar issue. The battery is 2 or so years old, and with the amount of charge/discharge cycles on it, i'm not surprised that it is on its way out. What I do is use a battery case, which is a case for the phone with a small external battery. This then recharges the phones internal battery, so i can then continue with my day and not have to worry about the phone dying in the middle of it. HTh. Sync issue Hello, Your battery is out of sync with the OS. To fix this, turn on your iPHone until it turns off. Turn it back on and keep using it again until it turns off. Keep doing this until the phone will no longer turn on. Then Charge your phone over night. If the problem persist, do the process over again. Exhausting the battery until the phone no longer turn on then charge it over night. On my Iphone 5, I have to do it twice. HTH and good luck.