what did i do wrong on this relay?

FiremanMatt3

New Member
Jul 1, 2010
10
check out my sketch of what i did trying to hook up my first relay and let me know what it wrong.


i wired it as shown in the sketch and the wire w/ the switch got hot and melted.


thanks guys

relay.JPG
 
May 24, 2010
1,627
PG County, MD
What size was the wire from the battery to the switch?


What type of wire(s) used?


What was the length of the run from the battery to the switch?


Do I understand that the ground wire to the relay also melted?


I don't see any fuse(s) in the diagram, are there any? if so, what size?


What kind of lights are powered off of the relay?


The more information you provide, the easier it is to make an educated guess at the issue.
 

FiremanMatt3

New Member
Jul 1, 2010
10
the main lights are a bunch of led's (10 body mounts) and 1 90watt strobe kit.


i used a 22g wire for the switch from 85 and 86


on 30 and 87 it was several 18g wires running through it since the lights are wired individually.


no fuses that time, i was just trying to see if it worked BUT i will NEVER do that again!!!


im assuming a 15amp fuse is ok for the switch line?


there was probable 6-8ft of wire from the battery to the switch.


the wires to the lights didnt melt, just the switch wire.


also, im not sure if i had 30 and 87 backwards or if it was as the diagram shows. same with the switch 86 and 87, does that matter if 86 and 87 are reversed?
 

bigcat

Member
May 20, 2010
641
Hartford County, CT
EL1998P71 said:
Looks like you wired it correctly, but you may have a bad relay, Shorted to ground across the coil.

I'd agree with that. I've never melted a ground wire, but I'm sure you'd have a similar event if you took a wire and touched it to the (+) and (-) of a battery with no fuse.


What kind of relay was it? I've learned that relays may appear alike, but a quality relay is worth the price. Once had a relay catch fire that came with a pair of Hella lights. Everything was wired correctly. One day the lights just stopped working. I opened my hood to find a relay that had overheated, melted, then caught fire [there were ashes]. The fuse never blew either, but was instead destroyed in the fire. :evil: Not Happy... to say the least. I would have been pissed had the damage been greater.
 
May 24, 2010
1,627
PG County, MD
FiremanMatt3 said:
the main lights are a bunch of led's (10 body mounts) and 1 90watt strobe kit.

i used a 22g wire for the switch from 85 and 86

Not even big enough, should be 16g minimum, 14g would be better. 22g is telco hookup wire and not meant to carry any amerage.

FiremanMatt3 said:
on 30 and 87 it was several 18g wires running through it since the lights are wired individually.

See above comment, 16g minimum.

FiremanMatt3 said:
no fuses that time, i was just trying to see if it worked BUT i will NEVER do that again!!!


im assuming a 15amp fuse is ok for the switch line?

No fuse is a bad idea, 25 Amp more than likely, what is the strobe supply fused for, 15 Amps? 10 LEDs at .5 amp per is another 5 amps for total of 20 amps, plus 10% makes it 22.5, so move up to the next size fuse at 25 amps.

FiremanMatt3 said:
there was probable 6-8ft of wire from the battery to the switch.


the wires to the lights didnt melt, just the switch wire.


also, im not sure if i had 30 and 87 backwards or if it was as the diagram shows. same with the switch 86 and 87, does that matter if 86 and 87 are reversed?

Bottom line, upgrade the wires from the battery for both power and ground, and add a fuse to both, 1 amp for the switch and 20 Amp for the relay.
 

FiremanMatt3

New Member
Jul 1, 2010
10
zack A said:
Fuse would have prevented that.
are you saying that if i were to put a 1amp fuse in the switch line that it would limit the power to 1 amp? my understanding is that the fuse doesnt limit the power, but it simply blows when power exceeds that. please correct me.

SlickTop Solutions said:
Bottom line, upgrade the wires from the battery for both power and ground, and add a fuse to both, 1 amp for the switch and 20 Amp for the relay.

let me ask you this... given the lights i have, could i wire them all to a single 12g wire? would that be strong enough? or would i need a 10g?
 
May 24, 2010
1,627
PG County, MD
FiremanMatt3 said:
are you saying that if i were to put a 1amp fuse in the switch line that it would limit the power to 1 amp? my understanding is that the fuse doesnt limit the power, but it simply blows when power exceeds that. please correct me.


let me ask you this... given the lights i have, could i wire them all to a single 12g wire? would that be strong enough? or would i need a 10g?[/quote:yref8x3g]


1 Amp fuse is fine from the battery to the switch for the relay, is should draw less than an amp to run the relay. You are correct in that it will blow when the current draw exceed the rating of the fuse.


12g should be fine for everything you have, if you have 10g readily available, use it. Don't forget to fuse the wire at about 25 Amps.
 
May 21, 2010
1,290
Minnesota
SlickTop Solutions said:
12g should be fine for everything you have, if you have 10g readily available, use it. Don't forget to fuse the wire at about 25 Amps.


Correct, but also make sure you are using automotive wire.


Have your main fuse as close to the battery as possible ( 6in ) if you are running directly from it. Be sure to also put a smaller rated fuse for the switch.
 

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