Power supply arduino mega

Hi

I am using the arduino mega 2560
And recommended power supply is 7-12 V
My supply wil wary from 12.7-15 V max.
Should I be to worried?
Any experiences?
It stands that the arduino input voltage limit is 6-20V

Specifications are correct. However, power supply voltage closer to low boundary is better (7-9V) otherwise the on-board regulator will get hot at higher current draw. The voltage about 12V and current above 200-300mA cause its heating.
Arduino board has not high power consumption so it should not be a problem but if you want to connect some additional HW (shields), the current can easily grow to 300mA.

The regulator is going to get pretty hot above 12V, and may even go into thermal shutdown, or fail.

See page 3, the 5V version is spec'ed for a rated output up to 800mA with only 12V in.
Above that, the part is dissipating a lot of power as heat: (Vin - 5V) x current = power dissipated.
So with say 14V in, (14 - 5) x 200ma = 1.8W. The 2560 can take up to 800mA, the 3.3V regulator will use some, the USB/Serial may be using some, the power LED uses some.

Lower Vin is better.

Some details on power calculations HERE

I see my problem is real ....
Thanks guys!