how to replace a 12volt 30amp auto relay with a Power Mosfet

Thread Starter


Joined Feb 5, 2007
I was wondering if someone can point me in the right direction. First I will give you a brief history of what I need. I race slot cars and on our controls we use 30amp automotive relay as a fully power relay to get the max power out of the cars in the straights. But the biggest problem is it makes the car twitchy because the relay is slow to react. So I would like to replace the relay with a Power MOSFET because they react faster and I won’t have to turn off the relay on the tight twisty courses.

Let me know if you can point me to a circuit that will work to replace a 30amp relay



Joined Apr 19, 2007
O.K....Providing that you are switching DC, yes a MOSFET could be used....Now if you are switching the +ve side of the supply, it will require a high side switching arangement, if you are switching the -ve (ground) side it is very simple....We need more info !!!!....Daniel.