Re: Fan Speed Controller
I bought and installed a controller from this guy: https://www.autocoolguy.com/
I saw him mentioned elsewhere on this site, and so far, I'm glad I bought one of his. His seem to be FAR FAR more rugged electrically than the regular brand names. His SMALLEST controller starts at 55 amps, and it just goes up from there. They do have pwm control, so the fans aren't screaming idiots as soon as you start the car. They have a cooldown timer set at 45 seconds or so. I took a look inside the one I bought, and as large as the rating is (200 amp), the output transistors are MUCH bigger than required. There are 10 transistors rated at 80 amps each, with each one individually fused at 25 amps. The build quality appears to be very good. It wasn't cheap, it was $250 delivered, but the lower rated ones are cheaper. I think this is a case of you get what you pay for. If you have very powerful fans, no unit from the better known names seems to be rated high enough to have some safety margin. This guy's stuff should take care of any fan setup you could possibly put on a road going vehicle, including a semi truck.
'71 chevelle, 468, TH400, 12 bolt posi w/3.08's, drinks a lot of 87 octane.