I have used different kinds of wall chargers, Samsung, HTC, Huawei, Sony. All of them have been 2.1A output with a high quality usb cable that is supposedly able to hold 4A back and forth. I might have been unlucky.
If the Hi12 is alot better to charge I will upgrade to it without doubt, it looks sexier aswell with that blue back. and less boxy back “cover”