olie05 Posted September 26, 2006 Share Posted September 26, 2006 In wiring a relay, is it possible to use the same power source for the actuating and actuated part of the relay?... Would this cause anything to act funny.... or is this how all relays are wired and im completely oblivious? btw, in this case, the switch would be wired in to interrupt the ground to the relay. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted September 26, 2006 Share Posted September 26, 2006 Olie, There is nothing wrong with doing that. Just make sure the main power source wire is big enough to run your load. Quote Link to comment Share on other sites More sharing options...
Bartman Posted September 26, 2006 Share Posted September 26, 2006 In wiring a relay, is it possible to use the same power source for the actuating and actuated part of the relay?... Would this cause anything to act funny.... or is this how all relays are wired and im completely oblivious? [attach]1391[/attach] btw, in this case, the switch would be wired in to interrupt the ground to the relay. I don't understand why you would want to do that. A relay allows you to take the load off your dash wiring, switch, etc. For instance when you upgrade your headlights with a relay you use the switch to activate the relay, and then get the power from a source that doesn't go through the switch. The power source would be heavier gauge wire with a more direct route to the alternator/battery. Quote Link to comment Share on other sites More sharing options...
olie05 Posted September 26, 2006 Author Share Posted September 26, 2006 I don't understand why you would want to do that. A relay allows you to take the load off your dash wiring, switch, etc. For instance when you upgrade your headlights with a relay you use the switch to activate the relay, and then get the power from a source that doesn't go through the switch. The power source would be heavier gauge wire with a more direct route to the alternator/battery. Right, but the ground to the relay would be the "thin" gauge wire with the activating switch. Reason for this is that in doing megasquirt the Fuel pump relay is grounded on the board itself. This would make it easy to run one power wire to the relay, one ground to megasquirt, and the "relayed" power wire to the fuel pump. (and O2 sensor). I'm looking for a clean install. Quote Link to comment Share on other sites More sharing options...
Bartman Posted September 26, 2006 Share Posted September 26, 2006 Right, but the ground to the relay would be the "thin" gauge wire with the activating switch. Reason for this is that in doing megasquirt the Fuel pump relay is grounded on the board itself. This would make it easy to run one power wire to the relay, one ground to megasquirt, and the "relayed" power wire to the fuel pump. (and O2 sensor). I'm looking for a clean install.If I'm understanding correctly, you would like to wire your fuel pump relay with a single ignition hot wire which would serve as the power for the pump as well as the power to activate the relay (meaning the fuel pump would always be on when the ignition is on). Is this correct? If so then I think VinhZXT gave you the right advice. Perhaps your saying that the relay switch is ground activated. I have a couple of ground activated relays in my install since the PCM activates several items with a ground signal. IIRC the wiring for that is different than what you posted. I can check my MAD Enterprises wiring book and post up a diagram if you need it. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted September 26, 2006 Share Posted September 26, 2006 I installed a lot of remote car starter and they used a lot of ground trigger signals and on the relay harness there is only 1 big red wire going to it. Then there is a small jumper wire from that big red wire to the + side of the coil of the relay. So yes you don't have to run 2 wires from the 12V source. GL. Now if you use a 12V trigger signal then you can't do that. I am sure you already knew that. GL Vinh Quote Link to comment Share on other sites More sharing options...
Buzz Posted September 27, 2006 Share Posted September 27, 2006 Is that ground on the coil of the relay or is that a double pole relay.If it's a double pole relay power is going to dead short to ground on that pic.The reason for using relays is for heavy loads,small control wires controll the relay and heaver load wires threw the contacts of the relay.Make sure you fuse it properly. Quote Link to comment Share on other sites More sharing options...
Guest harveje Posted September 28, 2006 Share Posted September 28, 2006 www.the12volt.com Will / can help you out. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted September 28, 2006 Share Posted September 28, 2006 Is that ground on the coil of the relay or is that a double pole relay.If it's a double pole relay power is going to dead short to ground on that pic.The reason for using relays is for heavy loads,small control wires controll the relay and heaver load wires threw the contacts of the relay.Make sure you fuse it properly. I agree, your picture makes no sense. You show a switch jumpering the power to ground. you don't show the field coil on the relay. That is the part that energizes the relay. Quote Link to comment Share on other sites More sharing options...
kcelectronics Posted September 28, 2006 Share Posted September 28, 2006 HI olie05 If you are just asking if you can use the same power source to power the relay coil, the simple answer is YES, it sounds like you have the basic idea and just wanted to check. This is a common practice:grin: Check out the 12v site http://www.the12volt.com/relays/relays.asp Quote Link to comment Share on other sites More sharing options...
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