I'm not good with electricity!

[babatten]

Okay so this may be a completely idiotic question but I have zero experience with wiring and don't wanna hurt myself so i'm gonna trust that someone here can help me.

I am trying to rig up a light system to use for flounder gigging on my boat and I plan to use some round GE car headlights I picked up for pretty cheap. I want to run the wiring through my pvc framing down to the lights and seal it off with silicone from the water but on the back of the lights are 3 prongs that i'm not sure how to wire up to a battery. Do I need one positive, one negative, and a ground or something else? I attached a photo of a light like mine with the 3 prongs on the back.

Any help would be greatly appreciated.

Thanks,
Brad

 

[bruceb58]

Re: I'm not good with electricity!

That is a dual beam headlight so you have one ground and one terminal for each filament in the bulb. You can use a meter to determine which terminal is ground by ohming all the terminals out. One terminal will be common to the two others and that will be your ground.

Or you can just get two battery leads and just do the same thing as a test. You can't hurt anything by picking two wrong terminals.

 

[babatten]

Re: I'm not good with electricity!

Okay so once I determine which post is for my ground would the other two prongs be for one positive and one negative?

 

[Fl_Richard]

Re: I'm not good with electricity!

No - Ground is negative positive can go on either of the two terminals remaining. For you car headlamp one is high beam one is low beam. You pick which you want - or use them both for a very bright light

Only two conductors are required. + and -

 

[Silvertip]

Re: I'm not good with electricity!

You will only use two of the three terminals. An auto headlight light you have is like two bulbs inside one larger one. One is high beam and one is low beam. Each beam needs a separate circuit feeding 12 volts to it (hence two positive terminals). But the ground can be shared -- hence the third terminal. If you have a very large battery powering this contraption you can certainly wire it so both beams are on rather than just the high or low beam. You don't need to even check for the ground terminal. Connect the + and - battery wires to two terminals. If the light comes on you are good to go. If not, move just one of them. The light will come on provided that filament is good. If both filaments are good, the only way you won't get the light to come on is if you happen by chance to pick the two positive wires. If you do that, nothing happens. If the three terminals really confuse you, go to WalMart and buy a high beam or a low beam light. They have only two terminals.

 

[babatten]

Re: I'm not good with electricity!

Thanks, that clears it all up. I was getting confused by three prongs but now I see what you mean with high and low beams. I know its not the most ideal setup for flounder gigging but as a college student I am on a limited budget and just need something that will work. I have two deep cycle trolling batteries and four of these lights so I was gonna run two off each battery and hope that it lasts for several hours. Thanks for all the help!

Brad

 

[bruceb58]

Re: I'm not good with electricity!

Low beams are around 40W and high beams are around 60W. At 12V, that corresponds to approxamitely 3.3 Amps and 5 amps respectivley. Use that as a rule of thumb to see how long you can run them. Use half of the battery capacity as your max allowed discharge.