Mosfet as a Switch

[Praneet]

Hey
So i was planning on using power Mosfets instead of industrial relay for all the electrical systems of our car.But it has drawbacks such as heating effect (need for cooling),and damage from stray voltages .It provides the advantage of reducing the effect size of the switching system . .Any ideas on how i can go on about implementing this ?

[jlangholzj]

very carefully....

Have you tested a circuit yet? Are heat sinks really necessary given the correct FET? Did your original relay solution have under and over voltage protection? Do you want current protection instead of voltage protection?

There's a few different ways to "skin the cat" on this one, some are more elegant than others but most would work fine.

[MCoach]

If all else fails...

[Tim.Wright]

Hey
So i was planning on using power Mosfets instead of industrial relay for all the electrical systems of our car.But it has drawbacks such as heating effect (need for cooling),and damage from stray voltages .All in all It needs to be equipped with over and undervoltage protection and a heat sink .Any ideas on how i can go on about implementing this ?

If it has so many drawbacks, wtf are you doing it???

[MCoach]

Praneet, are you planning on using a controller for systems that would be capable of handing these loads without the use of a relay?

In all honesty, we've designed for one relay on our car. It's the relay that controls the starter motor. injector, pump, spark, fan, and anything else we choose have all of their low side current sunk by the controller. Fuses we use, but relays are excessive.


I hope this gives some insight into our design theory...