Should I use 2 relays for fans and amps?

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Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=62732
Printed Date: May 12, 2025 at 7:44 AM

Topic: Should I use 2 relays for fans and amps?

Posted By: ghart999
Subject: Should I use 2 relays for fans and amps?
Date Posted: September 15, 2005 at 2:24 PM

I need to power on 3 amps, 2 crossovers and 6 12V fans from my HU remote wire. If I run everything through the same relay, will hte fans introduce electrical noise into the system? Should I put the fans on a separate relay from the components? If I do 2 relays, will they be isolated from eachother coming from the same distro block? Thanks all.

Replies:

Posted By: gcorrea
Date Posted: September 15, 2005 at 5:42 PM

i would go ahead and use two relays one for fans and one for the amps and crossovers. no you could get power from the same source.

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gcorrea

Posted By: KPierson
Date Posted: September 23, 2005 at 10:19 PM

ghart999 wrote:

I need to power on 3 amps, 2 crossovers and 6 12V fans from my HU remote wire. If I run everything through the same relay, will hte fans introduce electrical noise into the system? Should I put the fans on a separate relay from the components? If I do 2 relays, will they be isolated from eachother coming from the same distro block? Thanks all.

You shouldn't worry about inducing noise on your remote wires. You are adding a lot of stuff, and didn't give very much information. You would need to figure out the current draw of the everything, and see if you can fit it on one 30amp relay (shouldn't be a problem). The big problem will be making sure you use a wire big enough to support the current of the 6 fans and fusing it properly.

If you are using a distribution block (or any other 12 volt source in a car) then the voltage will not be isolated, as all voltage is generated by the alternator.

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Kevin Pierson