I dont unsetstand relays - Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > JK Jeep Wrangler Forum > JK General Discussion Forum

Join Wrangler Forum Today

Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 02-19-2014, 08:03 AM   #1
Fear The Post Count
houstonpdlt's Avatar
Join Date: Sep 2013
Posts: 290
houstonpdlt is on a distinguished road
I dont unsetstand relays

I can do lots of stuff, but electricity confuses me. Last weekend I hooked up two 12v plugs to my tailgate for kids phone charging, running spotlights etc. I direct wired them to the battery, with a 15a inline fuse. Is this ok or does a relay and/or switch need to be included in the mix?
houstonpdlt is offline   Quote
Old 02-19-2014, 08:25 AM   #2
Join Date: Aug 2013
Posts: 67
Eight is on a distinguished road
With proper size wiring and no load when the car is off (so you don't drain the battery), no, you don't need a relay or a switch. If you want to put a switch on it, whether you need a relay or not will depend on the current capacity of the switch.

Eight is offline   Quote
Old 02-19-2014, 08:49 AM   #3
Nuke83's Avatar
Join Date: Apr 2013
Location: NW of Atlanta
Posts: 789
Nuke83 is on a distinguished road
In your case, you don't really need a relay. Relays come into play when you have a device (horn, starter, lights) that run off a switch (i.e., toggle switch, starter switch, etc) that require a large current draw. Because of this draw, you need to have a supporting infrastructure to support that large draw so that it doesn't melt your wires, switches, etc.

Also, because large current draw equals high heat, wiring and switches that aren't designed to handle high heat will have a short life span as they will "die" sooner.

If you design a system by which all the wiring from battery/fuse box to switch, to device are strong enough to handle the load, then you're driving up the cost of the higher quality materials.

Enter the relay.

Basically, a relay is nothing more than a switch (but NOT like a traditional toggle switch) that handles the current flow between your battery/fuse box and device. You then wire a toggle switch to operate the relay. In a nutshell, you hit your toggle switch to turn the relay on or off, which in turn tells the relay to turn your device on or off. The load between a toggle switch and relay is very low, especially compared to the load between the relay and the device. So your toggle switch will last much longer, you won't melt it by running high current through it, and your circuit is much safer overall (melting/shorting wires will produce high heat which can produce fire). Also, you can purchase a 12v relay for about $10 or so, so it becomes more economical for high load devices.

Since you didn't put a switch inline (because you're considering running spot lights off the 12v run), you don't need a relay. Had you switched, it, I'd recommend using a relay since you have the potential for high draw. Not sure what gauge wire you used for your run, but based on the wattage of your spot likely being high, I hope you used 14 or better. I'd keep a close eye on the wiring when using the spot and see if the heat gets high. This would be an issue regardless of using a relay or not because of the draw to the 12v socket. Just keep tabs on it and don't leave it on for long periods if it gets real warm.

You included an inline fuse in your scenario, so you should be good. Even had you wired a relay into your circuit, you would still have wanted to use an inline fuse, so you should be good.
Nuke83 is offline   Quote
Old 02-19-2014, 09:00 AM   #4
Fear The Post Count
houstonpdlt's Avatar
Join Date: Sep 2013
Posts: 290
houstonpdlt is on a distinguished road
Thanks! I used 14 gauge, with the exception of the first few inches off of the battery with the inlne fuse, which is a tad bit smaller. It came with my KC HID lights. Guess im safe. I appreciate the quick help.
houstonpdlt is offline   Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 07:01 AM.

User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC
« Back

Enter your email address:

Delivered by FeedBurner