Problems with iPhone 4S

The charger is actually quite good. However, appear sporadically on my iPhone 4S, the message "charging with this accessory is not supported", especially when the battery is discharged below 40%. In this case I have to make a reset the phone, so that the charging works with charger.
I made that mistake neither the original Apple charger still at a different charger. Thus, I assume that the charger is faulty. According to information from the dealer the problem is on my phone. The charger is properly ... who believe it ... ^^

Summary: Nice charger when you do not have iPhone 4S. Otherwise not entirely compatible and poor service. Prefer to buy the original and have no problems.