Connect 4 x 12v dc motors

It means that when the motors start up from standstill, they will each draw 60A. Also if the motor is prevented from rotating, it will try to draw 60A.

I suggest you choose a motor controller with built-in current limiting, to constrain the startup current to a more reasonable value. It's possible to use the Arduino itself to do the current limiting if you choose a motor controller with current sensing, but then you need to get the software right or you risk damaging something.