My Nokia Lumia 520 with the Cyan 8.1 upgrade but without any other ones eg. 8.1 update 1 update 2 etc which have now had for about a year come Jan '15, has developed a charging problem as in it takes almost all day or overnight to fully charge. This has only happened recently like a week ago Dec '14, so even if keep charger plugged in the charge drops off. Help please.
Try re-installing the battery. Also check if the charger you are using is still in good shape. Are you using original charger?