I would just like some advice since I melted a USB cable today
and I realized I don't have the proper troubleshooting skills.

I bought over a half-dozen "Hype Volt" 6.8Amp USB chargers for
stuffing the Christmas stockings:
https://i.imgur.com/Zavgm4B.jpg

I kept one for myself, but, when I used it last night on an iPad
and on an Android phone, the iPad lightning cable melted!

When I pulled it off the iPad, it was noticeably extremely hot,
but it doesn't seem to have damaged the iPad (AFAIK).

So, I'm just wondering what happened, and, more importantly, when
I look at the specs for this device, they don't make sense to me,
so, I have difficulty troubleshooting what the problem is/was.

Here are all the specs off the package and off the device:
DGL Group Ltd. Hype Volt HV-6PT
Model: HC363-5U (also listed as HV-6PT-WHT)
Input: AC 110VAC/60Hz - 220VAC/50Hz (800mA max)
Output: DC 5V, 6.8A total
Maximum Power: 40W
Supercharge: maximum
Universal: 5V@1A maximum

Description:
http://www.amazon.com/Hype-Compact-A.../dp/B00T3FQBHO
http://www.walmart.ca/en/ip/hype-vol.../6000193376994

My questions are varied, because I don't understand how it works,
nor how it could have overheated the cable to the tablet.

Here's what it says on the package:
"Smart USB Technology: This adapter automatically adjusts power
output to fit your charging device. Tablets and e-readers require
2 Amp charging, and this adapter will reroute power to the
appropriate USB port you use."

"Charging Combinations:
- 2 tablets + 3 mobile devices
- 1 tablet + 4 mobile devices
- 5 mobile devices
- 3 tablets"

I am confused about both the pure math and how this operates.

Q1: Since 6.8A times 5VDC is only 34Watts (not 40 Watts), how
can they very clearly label it as a 40Watt device?

Q2: How does the device "know" to give tablets 2.4 Amps
(12 Watts) but a "mobile device" only 1Amp (5 Watts).

Q3: What if a mobile device "wants" more than 1 amp?
Does the charger give more than 1A to the device?