I connect a motor with a logic mosfet to control it in the simplest circuit. (+ battery -> motor -> mosfet -> - battery) and an arduino to provide 5v to the gate of the mosfet. The battery is 12v.
The mosfet have a nive 5v gate to source and should be fully open and should be able to lets about 110 amps which I think it's enough for my motor to go to it's full potential without any load.
That device has an absolute max current rating of 62A, it will need heatsinking above about 8A (and I
wouldn't be tempted to put more than 20A through it really, the abs max current rating is not a place
you want to operate at (and remember the max current for 5V gate drive will be sifnificantly less)
The problem is that the motor doesn't as fast as when I connect it directely to the battery and does not accelerate as fast it should be.
I really don't understand, the motor receives a nice 12v and I 110amps should be enough.
That motor has a stall current of 100A, beyond the MOSFET's handling at 10V gate drive,
and even further beyond its logic-level handling. (*)
Try parallelling 3 of this MOSFET type (remember gate resistors when paralleling), or get
a higher performance mosfet.
For such high powers I'd never dream of using a logic-level MOSFET, they are much less
robust. Get a normal 10V gate drive MOSFET of about 2 milliohm or less on resistance driven by
something like a MIC4422 mosfet driver which will actually be able to handle driving the
large gate capacitance comfortably. Add a 15 zener between gate and source to protect the
gate oxide from transients too.
As an example, here's a capable device:
(*) Maximum on current is related to the thickness of the conducting channel between
source and drain, which depends on the charge on the gate-source capacitance, and
thus the gate-source voltage - any logic level MOSFET will carry more current at 10V than 5V
(and the on-resistance is lower)