Universal wireless charging pad 5W 7.5W 10W 15W and phone heat

[Kiriakos GR]

I received as a gift, a modern Universal wireless charging pad. 

Mobilize Strong Magnetic MagSafe Compatible Wireless Charger 15W White
Product code :  MOBMCC002

I had never see before, a Universal wireless charging pad.
While I have good experiences with 5W Samsung Qi pads and chargers.

Indeed wireless charging this causes heat. 
The higher the charging wattage, more heat this is expected to be produced.

How high is the safe temperature range for wireless charging? 
The baseline this is approximately 45 Celsius.

12 years ago Samsung designed wide desktop pads, first design this was not that perfect as it was airtight.
This blocked wireless charging pad ventilation.
Next Samsung model came better designed, a round pad of some height, plus ventilation holes.

Today ... there is another hybrid design out there =  wireless charging pad + magnetic 

Long story in sort, miniature magnetic wireless charging pads , they are designed for performance.
Large in screen dimensions mobile phones, they will in theory dissipate heat, at their phone body.

The actual Universal wireless charging pad, while it looks plastic, there is at it  interior a round aluminum plate, this working as a heatsink.
In conclusion, portion of the heat this is released due the charging pad exterior body.
And also a second portion of heat this is dissipated by the phone.

What is the best advice in all this?
Use a wireless charging pad only for overnight charging, when the phone this is not used for anything else.
If you are heavily concerned of 40C temperatures at charging, while your fear is unjustified, then just shop for a pad this supporting less watt power. 
 
From the other hand, modern mobile phones, they have a temperature sensor,  the phone will stop wireless charging by it self, and charging this will recover when the phone this decides that is safe for it.