Relay Help

Firecar96 · Post by **Firecar96** » Sun Apr 01, 2007 1:16 pm

Well my posts were removed, so I have to start over.

I have noticed in a lot of people install pics they are using relays, solenoids and circuit breakers. I was wondering what the solenoids do, what is there purpose. Also what kind of relay should I use to install some led lights from sound off. Can someone tell me how to figure out the difference between different types of relays. I dont understand the wiring diagrams for each one. I am going to install two Sound off led sticks. One with 8 modules and one with four modules. I am in a hurry at the moment so I cant explain to in depth. My in depth posts were removed, and I dont have time right now to rewrite them. I will try to later. If anyone could help that would be awesome.
Thanks

Firecar96 · Post by **Firecar96** » Sun Apr 01, 2007 10:18 pm

Ok I did some research into relays and learned alot. The only thing that confuses me is what the difference is between posts 87 and 87A, on a SPDT Relay.

thebigphish · Post by **thebigphish** » Mon Apr 02, 2007 2:38 am

#87 & #87a are different in that one will be normally open (commonly referred to as NO), and the other as normally closed (referred to as NC) When the relay is cold, the contact that is normally open will be....you guessed it....open, and the NC contact will be (guess here!) closed. When current is supplied to #85 & #86 (the actuator leads) the coil will energize, and the relay will go hot, and it will close the NO post, and open the NC post...thus reversing its' state.

An example as to what it will do for you (pardon me, on the bad half of 36 and have not slept yet, but my glucometer tells me i can still type w/o legal ramifications

)...

If you have a relay with the #87 & #87a option set up to go active when your trunk opens (so you grabbed current off your trunk open switch to go thru #85 & #86 - follow me?) you can have a common power coming in thru #30, and #87a (the NC post) going to your rear deck lights, and #87 going to your cool trunk lip lights that take the place of your deck lights that are now obscured by your open trunk. The #87a (NC) lead will allow your deck lights to be on when the trunk is closed, because the relay will be cold, and the NC power will go to the deck lights, when that trunk opens, the relay goes hot, the contacts close, the #87a goes open, shuts off the deck lights, closes the #87, activates the trunk lip lights, and you have lights on for coverage from behind.

YMMV, based on your install...but with this relay knowledge for you, you can only imagine the interesting things you can do...

Firecar96 · Post by **Firecar96** » Mon Apr 02, 2007 9:46 am

That really helps, Thanks

So what are solenoids used for?

Post by Pj » Mon Apr 02, 2007 2:45 pm

http://en.wikipedia.org/wiki/Solenoids

Firecar96 · Post by **Firecar96** » Fri Apr 13, 2007 5:08 pm

I read the definition of a solenoid from the link I was given, but I still don't completely understand them. What is it that they do when used in light and siren set ups? Why are they used? Can anyone give me a simpler explaination of what they do and why there used.
Thanks

thebigphish · Post by **thebigphish** » Fri Apr 13, 2007 5:46 pm

they are often high current relays that are designed (remember relays are designed for intermittentent use) high current applications, or constant duty, or for moving a "tough" switch (like the solenoids that turn the water on and off in your washing machine). Relays heat up, because they are not designed to be constantly on, solenoids are.

Firecar96 · Post by **Firecar96** » Fri Apr 13, 2007 6:36 pm

So they are more used on larger light set ups, large lightbar, multiple radios, other lights, exc?

If I have two Sound Off grille LED's a Whelen 90 watt strobe power supply and a Code 3 Mastercom siren, would I want to use a solenoid or would a 75 amp Bosch relay sufice?

If my wiring diagrams show a fuse is required, could I just use circuit breakers instead?

How many amps can the average 8 guage power wire handle?

Post by **Code3Response** » Fri Apr 13, 2007 10:05 pm

FireCpt809 · Post by **FireCpt809** » Sat Apr 14, 2007 6:41 am

Firecar96 wrote:So they are more used on larger light set ups, large lightbar, multiple radios, other lights, exc?

If I have two Sound Off grille LED's a Whelen 90 watt strobe power supply and a Code 3 Mastercom siren, would I want to use a solenoid or would a 75 amp Bosch relay sufice?

If my wiring diagrams show a fuse is required, could I just use circuit breakers instead?

How many amps can the average 8 guage power wire handle?

Ive been installing 10+ years I have never needed to use a selenoid. If your switching and wiring is correct there is no need for a Selenoid. I have used 75 amp relays for master ignition and some applications. It has alot to do with how much you load the circut .

With your set up You can use 2 30 amp relays What is wired to the battery and what is on ignition? The Power supply should have a dedicated Battery on the red and the colored wires are just turn ons. The grill lights maybe pull 7 amps. The siren if you are running off ignition should be 20 amps. The switching part of the master com can be hooked directly to battery, It only draws power when the lights are on. With the Grill LEDs and strobes the most you would be pulling is maybe 15 amps through the switch

8 guage depends on the length of the run. I dont like to go over 80 amp for more than 10 ft.

Relay Help

Relay Help

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Solenoid