rusty_wingnut Posted July 14, 2012 Share Posted July 14, 2012 I've read it's possible to control an electric fan with megasquirt and the relay board. I am looking for an idiots guide or some pointers on this. Cheers Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted July 15, 2012 Share Posted July 15, 2012 In software, you enable an output when the temperature goes over your setpoint. In hardware - you'll need a transistor switch circuit (identical to the fuel pump circuit) to drive a relay which will then switch your fan. I'm sure there's info in the megamanual on both. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 16, 2012 Share Posted July 16, 2012 The missing info: http://www.extraefi.co.uk/Drawings/PDF_Files/coolingfan.pdf Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted July 16, 2012 Author Share Posted July 16, 2012 Excellent! Nice one Fridge Quote Link to comment Share on other sites More sharing options...
Dave W Posted July 16, 2012 Share Posted July 16, 2012 If you're not using the FIdle output or you're upgrading it for use with a PWM, I use the original FIdle circuit to control the cooling fans and reroute the PWM FIdle through a spare pin. The FIdle output is identical to the fuel pump output in standard form and you normally end up modifying that circuit anyway. It;'s a habit I picked up when I was using v2.2 boards that didn't have the prototyping area or the spare pins that the v3 board has and I've pretty much stuck with it. The transistor is capable of handling 2 relays quite comfortably so if you have 2 fans I use a relay for each and a fuse for each so you have redundancy in the system should a relay fail or a fuse blow you should have at least one fan running. Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted July 17, 2012 Author Share Posted July 17, 2012 I am not using the Fidle as it goes, currently I've only wired the system for the sparks side. Good to know - thanks for the help Quote Link to comment Share on other sites More sharing options...
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