jevansio Posted July 4, 2009 Share Posted July 4, 2009 Can anyone tell me if what I want to do is possible. Basically my electric fans are controlled via a relay when the ignition is switched on. What I want is a delay (say 10 sec) when the fans come on after the ignition is swicthed on. Is there a simple component I can buy that you just put a 12v ignition feed in one side & you get 12v out the other side 10 sec later. Quote Link to comment Share on other sites More sharing options...
Guest P13SST Posted July 4, 2009 Share Posted July 4, 2009 Why would you want to do this out of curiosity? Most fans run at 6v per fan at low speed. To make your self with a resister, transistor and capacitor through a reverse connected base junction... i.e. a pain in the ass. I would imagine this type of component would exist in some household gadgets... Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 4, 2009 Author Share Posted July 4, 2009 I'm moving to a Varley Red Top 25 battery as my car is basically a road going track car (no ac, heater, stereo etc). I don't want any additional strain on the battery when I crank it over, I want the fans to start after the motor is running Quote Link to comment Share on other sites More sharing options...
Guest P13SST Posted July 4, 2009 Share Posted July 4, 2009 what about a manual switch? Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 4, 2009 Author Share Posted July 4, 2009 what about a manual switch? The easiest solution, but my memory ain't that good Been looking at delay relays & I think they may be what I'm after, didn't realise they'd be so expensive, around a tenner for a bit of electronics (the NOTC one) http://www.allaboutcircuits.com/vol_4/chpt_5/3.html Quote Link to comment Share on other sites More sharing options...
Kev.O Posted July 4, 2009 Share Posted July 4, 2009 Jay, I've used two of the outputs on the ECU to switch the relays when the water gets up to temperature. It's really not that difficult I even fitted two LED's so I know when the fans come on. Quote Link to comment Share on other sites More sharing options...
Guest P13SST Posted July 4, 2009 Share Posted July 4, 2009 Lol, mines ain't that great either but i like switches :s, makes me feel in control. Well tbh, it would save you 'building' one your self which may take an hour or so of your time so is your time worth more? Plus its likely going to have a tidier appearance than DIY wiring. Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 4, 2009 Author Share Posted July 4, 2009 Jay, I've used two of the outputs on the ECU to switch the relays when the water gets up to temperature. It's really not that difficult I even fitted two LED's so I know when the fans come on. Yeah I know that's how Ryan usually does it, does that mean your fans are on before cranking if you're doing a warm start, I want to avoid anything being on before the motor is running due to choosing a low capacity battery? Lol, mines ain't that great either but i like switches :s, makes me feel in control. Well tbh, it would save you 'building' one your self which may take an hour or so of your time so is your time worth more? Plus its likely going to have a tidier appearance than DIY wiring. An automatic switch (no matter how untidy) will be tidier than a manual one though , I thought this sort of thing would be an off the shelf item? Quote Link to comment Share on other sites More sharing options...
Kev.O Posted July 4, 2009 Share Posted July 4, 2009 Yeah I know that's how Ryan usually does it, does that mean your fans are on before cranking if you're doing a warm start, I want to avoid anything being on before the motor is running due to choosing a low capacity battery? Good point. They would still come on with the ignition if the water was up to temperature. Only thing I would say, is that the engine should be easier to turn over if it's warm right? I believe you have the same fans as me, which drew 8 Amps each when first started (dropping considerably once going). Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 4, 2009 Author Share Posted July 4, 2009 Good point. They would still come on with the ignition if the water was up to temperature. Only thing I would say, is that the engine should be easier to turn over if it's warm right? I believe you have the same fans as me, which drew 8 Amps each when first started (dropping considerably once going). It prolly not an issue when carrying a big battery, yeah same fans. Wonder if I'm being too apprehensive. Pretty sure Wez runs the Varley 25, might see if he's had any issues so far Quote Link to comment Share on other sites More sharing options...
Kev.O Posted July 4, 2009 Share Posted July 4, 2009 It prolly not an issue when carrying a big battery, yeah same fans. Wonder if I'm being too apprehensive. Pretty sure Wez runs the Varley 25, might see if he's had any issues so far It shouldn't be that difficult to install a timer relay, just to be on the safe side. It's only a tenner... Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 4, 2009 Author Share Posted July 4, 2009 I'll ask the lads at work which one to get, they're all electronics geeks Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 16, 2009 Author Share Posted July 16, 2009 Managed to get something sorted, a guy at work made me a little circuit using a 555 timer Quote Link to comment Share on other sites More sharing options...
Kev.O Posted July 16, 2009 Share Posted July 16, 2009 Managed to get something sorted, a guy at work made me a little circuit using a 555 timer Wow that brings back memories from my electronic days. Quote Link to comment Share on other sites More sharing options...
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