Electrical Help

[BlackBeauty]

So I am making a light bar for my truck... On it there will be 4 lights, the 2 outsides will be driving lights, and the 2 insides will be long range... The lights will be converted to HIDs... Each set will be controlled by a rocker switch inside the cab... A few questions... 1.) Is there any specific amp switch I need? I was looking at them on Summit, and there is a large range of amp switches, from 15 to I think 30... What do I need for my application? 2.) What gauge wire should be used when hooking them up? 3.) Are 5k 35w driving and 5k 55w long range good setups for the lights? 4.) A simple explanation for the required wiring would be, battery to switch (with fuse) , power from switch to lights, and ground from switch to lights, sound about right? Any help is appreciated!!

 

[hiredgun8]

1.) 15 Amp will be heavy enough for either set...110W divided by 12v = 9.16A..so 15 is plenty
(If you use the switch to turn on a relay then a 1A switch would be enough)
2.) 14awg will be plenty heavy
3.) Should be plenty of light...That's for sure.
4.) Battery to switch...switch to lights ....ground from lights to frame...Switch does not get a ground unless it is a lighted switch.

 

[BlackBeauty]

1.) 15 Amp will be heavy enough for either set...110W divided by 12v = 9.16A..so 15 is plenty
(If you use the switch to turn on a relay then a 1A switch would be enough)
2.) 14awg will be plenty heavy
3.) Should be plenty of light...That's for sure.
4.) Battery to switch...switch to lights ....ground from lights to frame...Switch does not get a ground unless it is a lighted switch.

Sweet thanks man! Yeah they are lighted switches that I had been looking at, but I got confused when typing so yeah

 

[orangeastre]

I would not run the switch directly to the lights,this is a invitation for trouble.You want to be able to control one bank of lights per toggle switch,correct?In order to do this you will need two switches,and two relays.By doing this we are taking the load off of the switch and letting the relay do the work.I will go out on a limb and assume that you will be using a standard Bosch style 5 pin relay,you will be wiring pin 85 to ground,pin 86 to the positive trip from your switch.Pin 30 will be wired to the lights and pin 87 will be the fused 12 volt battery feed.Hopefully this helps.

 

[hiredgun8]

Why would this be an invitation for trouble?

It's less moving parts which is always good. Less connections to fail.
Each set of lights is well below the switch's amp rating.
Would you go through your house and wire relays into every light switch?

 

[orangeastre]

The invitation to trouble lies in the current load the switch is being asked to pass.The math you presented assumes that the switch is mounted directly to the lights,it allows for no voltage drop along the wiring run.It also does not factor for the unknown current draw of the HID ballasts that the OP plans to install.While there is some truth in the less connections to fail mentality,there is also something to be said for the reliability of a relay as opposed to a switch.It also will allow the lights to triggered by parklights or acc.,as opposed to battery(always on) power.

My career is in the automotive electrical business and has been for the last 15 years. I always err to the side of caution,especially when giving information out on the internet.I would prefer someone over engineer something as opposed to the other alternative.but that is just me.

 

[BarronTG]

The invitation to trouble lies in the current load the switch is being asked to pass.The math you presented assumes that the switch is mounted directly to the lights,it allows for no voltage drop along the wiring run.It also does not factor for the unknown current draw of the HID ballasts that the OP plans to install.While there is some truth in the less connections to fail mentality,there is also something to be said for the reliability of a relay as opposed to a switch.It also will allow the lights to triggered by parklights or acc.,as opposed to battery(always on) power.

My career is in the automotive electrical business and has been for the last 15 years. I always err to the side of caution,especially when giving information out on the internet.I would prefer someone over engineer something as opposed to the other alternative.but that is just me.

+1 Relays are always the way to go

 

[Wstrnsky]

I have relays for all my lights. Alittle more wiring and thought but much better light output and safety.

 

[great white]

The invitation to trouble lies in the current load the switch is being asked to pass.The math you presented assumes that the switch is mounted directly to the lights,it allows for no voltage drop along the wiring run.It also does not factor for the unknown current draw of the HID ballasts that the OP plans to install.While there is some truth in the less connections to fail mentality,there is also something to be said for the reliability of a relay as opposed to a switch.It also will allow the lights to triggered by parklights or acc.,as opposed to battery(always on) power.

My career is in the automotive electrical business and has been for the last 15 years. I always err to the side of caution,especially when giving information out on the internet.I would prefer someone over engineer something as opposed to the other alternative.but that is just me.

I like the way you think!

Cheers

 

[Half Assed]

Why would this be an invitation for trouble?

It's less moving parts which is always good. Less connections to fail.
Each set of lights is well below the switch's amp rating.
Would you go through your house and wire relays into every light switch?

Why would the connections fail?

If anything, the switch would fail. Would get dirtier faster over time from arcing with higher amperage. I've never had a relay fail, but I have had switches stop working.

A relay will handle the heat better and I don't like the idea of having 2 hot switches in my dashboard. Also, if you use a relay, you will bypass the dash and there is less risk of a short under the dash.