My sons iphone 5 is about 18 months old. About a month ago he said the battery wasn't holding charge very well and was dropping by 20% in a few seconds etc, occasionally it came up with "this accessory may not be supported" and wouldn't charge, but this problem was sporadic. Bought new charger (genuine apple) but problem remained, both chargers work fine with my iPhone 5. Reached the point where it was barely charging at all so took it for repair, they said it was the battery so replaced it. Got it back today (it was at 46% charged)was advised to let it drain completely before recharging, lo and behold the error message came up when it got to 24% charge and it won't go any higher, although it's holding that charge which it wouldn't before (it would drain really quickly). Any ideas?!