12v power from relay to relay?
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=70499
Printed Date: June 02, 2024 at 9:55 PM
Topic: 12v power from relay to relay?
Posted By: shawzie
Subject: 12v power from relay to relay?
Date Posted: January 10, 2006 at 8:11 PM
Is it all right to jump constant 12v power from relay to relay to relay from 1 wire from the battery,or is it better to run seperate power to each relay.I could see if multple relays were engaging at the same time it would draw higher amps but if there engaging seperatly it should be all right?
Replies:
Posted By: Mike M2
Date Posted: January 10, 2006 at 8:15 PM
That's fine as long as you run a wire heavy enough to handle the load. It's rare to have to ever run to the battery for anything, usually you can find enough amperage right inside the car....
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Mike M2
Tech Manager
CS Dealer Services
Posted By: dualsport
Date Posted: January 10, 2006 at 10:48 PM
Yeah, you can run a single wire provided it's sufficient to handle all the loads you're planning to put on it, and fuse it at the battery. From there you can get a distribution point inside the car at a convenient point, and if you're running smaller wires from there, you need to fuse them all separately, because it can be a hazard if something shorts on the end of the small gauge wire- the big fuse at the battery won't blow in that case, and you risk a meltdown of the small wire, which is essentially unprotected.
Any time you go from a heavy gauge wire to a smaller one, it should be fused separately with the appropriate size fuse for the wire.
Posted By: shawzie
Date Posted: January 10, 2006 at 11:58 PM
So could I prewire my harness so that all my 12v constant was spliced into that 1 wire and then I would only have 1 12v constant connection to make in the vehicle correct.
Posted By: shawzie
Date Posted: January 11, 2006 at 7:25 PM
1.Does anybody have a chart showing how much current each wire gauge can handle? 2.Is it better to ground everything individually or can you splice all your grounds into 1 wire and then just ground that wire to your vehicle? Thanks in advance for any replies.
Posted By: sparkie
Date Posted: January 11, 2006 at 7:31 PM
It depends on the length of run of the wire to a certain degree. If you are activating many different circuits, one or more ground is ok. If you are grounding audio components, one ground is usually better as it helps to keep the dreaded ground loop away. It causes noise to enter the system. Post more info on what you intend to use each relay for or what load each relay must carry.
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sparky
Posted By: shawzie
Date Posted: January 11, 2006 at 7:59 PM
I have 5 grounds in total,2 for relays,1 for r/s and 2 for door locks.should I put 5 into 1 and then ground that to the vehicle or all seperate?Then my clutch bypass relay needs 12v constant so I was going to tap into my jeeps constant 12,so what should I fuse that at?
Posted By: Mike M2
Date Posted: January 11, 2006 at 9:17 PM
Not sure what you are using the relays for, but it doesn't sound like you are in need of a large sum of amperage. The remote start draws little, relays very little, and if you are talking about aftermarket door actuators they use less than 10 amps. All this could be had right at the ignition switch, why go to the battery? As for grounds, again we aren't talking a ton of amperage, a good secure ground in any fashion you wish would be fine. ------------- Mike M2
Tech Manager
CS Dealer Services
Posted By: rdlybeck
Date Posted: January 12, 2006 at 3:45 PM
Along the same question what size fuse should you use when connecting a relay to power? Such as door lock relays for remote start. Is there a chart or something for fuse recomendations? Thanks ------------- Ryan Lybeck
"Wiring diagrams are nice but still double check with DMM"!
Posted By: dualsport
Date Posted: January 12, 2006 at 4:08 PM
Yeah, it'd be best to start with the actual current usage of the things you're powering up in normal operation like bobk says-
If you can't measure it or for just general fusing to protect the wires, this looks like a good reference:
Guideline for current handling of different wire gauges
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