Hey guys! Im running Nathan K5 horns with a Viair 450 compressor to a 10 gallon tank. Im buying from auto parts the Ford style starter relays. Think they are 30 amp not sure. But I have burnt up 2 in 2 days!!! I have just 10 Ga wire coming off my hot so Im thinking its too small so I got some welding lead wire from work. Will this maybe keep the relays from blowing? And there is no ground wire to them Im grounding them by bolting them in my toolbox which is bolted to my bed. Does this seem legit?
Howdy and welcome to the forum. OK… now here’s my take on it.
- Viair 450 should only draw 20A max so you should be right with your relay
- Depending on the length you’re running, the 10ga wire is marginal (ie. any more than 15 feet and you should go a bit thicker; 8ga for example).
3)The way you have your ground wired is a no-no. Truck beds are notoriously bad for grounding out circuits and if you combine that through a toolbox you’re asking for trouble. Run a good lead straight back to the negative or the actual chassis. If you have a multimeter you can check your resistance across the ground path - in your case I’m betting its very high.
Its a 97 xcab chevy. Its roughly 18 feet or wire. So how should I actually ground the relay? It has 4 prongs and neither of the prongs say its a ground. I have my tank comp and relay bolted to a clean 3/8" aluminum screwed to my toolbox bottom through my floor also. Is it possible to run a wire from frame to that sheet of aluminum or run a wire up from frame and wire nut the ground to it?? How do i need to ground the relay??? It is grounded by being bolted to the alum there is no ground wire to it and no spot for one
I should also add that you should be running twin compressors for filling 10 gallons. The only single 12V compressor that covers manufacturer support for 10 gallons or more is the venerable Oasis. Even with a single OB2 you’re limited to 5 gallons.
So although I doubt it’s the root cause of your issue, it’ll play a role since the compressor needs to work very hard to fill that much tank.
Have a look at this thread here. I’ve got a diagram in there about how to wire in a relay. The relay itself doesn’t need a ground other than for the trigger (which is very low amperage, so your toolbox is fine for that). The compressor however is a completely different thing and needs a very good direct ground connection - but that doesn’t involve the relay.
https://www.trainhornforums.com/showthread.php?t=6366
I agree its working very hard lol. But im in all this for free so i wasnt gonna pass it up. Guy helped me install it has done some but im thinking run a ground from frame to comp then comp to the bolt that holds relay to plate and the welding lead wire for power will keep from burning up relays??? And btw i never let it get below 80 psi and pump to 130 psi so yes its working hard but at least not too hard lol
Welcome to the forum. Keep in mind, it might be working hard enough to shorten its life.