wiring my boat lights - front and back only

Joined
Jun 3, 2008
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hey everyone i have a quick wiring question. Does anyone have a good diagram that i can use to wire up some boat lights. I bought a light for the front (red/green) and one in the back (white) I bought a switch. When i wired them all up i tested it on a 9V battery and it seemed to work really good. I took it to my boat and put it onto the battery and the lights worked but then i got a lot of smoke and the wires burnt up.... I dont know what i did wrong and i dont know how to wire them so this doesn't happen again. any help would be great. Thanks a ton in advance,
John
 
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Re: wiring my boat lights - front and back only

also i would like to put in a bilge pump and a electric anchor. how would i go about putting these things in also? would they would be all on there own switch. i was thinking 2 switches for the lights. one for the bilge and one for the anchor (up and down) possibly a depth finder in the future. thanks
 

fishrdan

Admiral
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Jan 25, 2008
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Re: wiring my boat lights - front and back only

If you smoked the wires either you have a short to ground or the wire gauge is too small. I would run a $30-40 fused switched panel off the battery so you can run each of the circuits (bow light, stern light, FF, interior lights, bilge pump, etc.) independently. I don't know the power requirements for the anchor lift, but it might exceed the rating of the fuse panel circuit. If so, you need to connect this direct to the battery with fuse close to the battery. Make sure not to use the boat hull as ground and insulate the wires well.

In my modded jon boat I have all the circuits run off a fused switched panel that's within reach from the drivers seat.
 

Silvertip

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Re: wiring my boat lights - front and back only

Here is what the nav/anchor light switch wiring looks like. Be aware that you either need two switches (one for each light) or you need a special single switch as shown in these two diagrams. Many people misunderstand how these light are to be used. When under way, both the front and back lights must be on. When stopped or at anchor, just the stern light is on. The reasoning is that when both front and back lights are on, other boats know you are moving. If all they see is the white anchor light, they know you are not moving.

This is a simple on-off-on switch that you can get at Radio Shack. You need the diode for this type of switch.

Nav-AnchorSwitch.jpg


This is also an on-off-on switch but the extra poles allows you to eliminate the diode.

NavSwitchWiring.jpg


To wire any device whether its a bilge pump, light or fish finder, here is a simple diagram. Just replace the light(s) with whatever device you are adding.

LightingCircuit.jpg
 
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Re: wiring my boat lights - front and back only

so i shouldn't be using the battery (neg) as a ground or use it at all? thanks
 

Silvertip

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Re: wiring my boat lights - front and back only

Ground IS the negative terminal of the battery or the engine block, or the negative terminal on a fuse panel. They are all the same points electrically. If you don't have a fuse panel, then that leaves the battery or engine block.
 

brianvolt7

Chief Petty Officer
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Jun 7, 2008
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Re: wiring my boat lights - front and back only

The switch you found on eBay looks good. Make sure that you use the right size fuse for the lights. This panel is equipped with ten amp fuses which do not offer enough protection for your lights; a smaller amp fuse will work better. As far as you smoking wires, you have what is known as a wiring SHORT. A short is when the wires touch each other and create a 0 resistance path to ground, about 10,000 volts on a battery. Do yourself a favor and dont hook up any wire without fusing it first, if you had heavy gauge wire it could have created a battery explosion. You will probably need to charge up your battery after the incident. Check your wiring first, make sure that there is not any bare wire, use tape or Home Depot/Radio Shack sells shrink tubing. Make sure you fuse everything before applying power or you will be throwing money out the window. Each item you purchase will have the fuse size listed; I would recommend installing only that size fuse. Another innocent mistake is that on your switch you only switch the positive leg, the negative leg home runs from the device to the ground reference (battery term or engine block). The +&- never tie down on a switch together. This may be where all the smoke came from. I?m glad it?s only 12volts and not 120 or 480! Good luck.
 
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Re: wiring my boat lights - front and back only

oh ok gonna be cheaper and help the sight out. gotcha. here is my master plan . Get a couple 1 watt fuses for the lights and then go from there. the light that i got said use a 1.Watt fuse. as for the grounting... gonna do this to the engine. i figure thats the safest bet.
 

Silvertip

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Re: wiring my boat lights - front and back only

Lets clarify some terminology. Fuses are rated in AMPS -- not WATTS. You would look a long time before you found a 1 watt fuse. Grounding to the battery is the safest -- not the engine block and you wouldn't need to run the wires inside the engine housing. The battery is the electrical power source for your boat -- not the engine. The engine merely recharges the battery. I would suggest you buy a basic DC wiring handbook and study a bit before doing this. Lastly, the POS and NEG wires from the battery need to be larger than the wires from the new switch panel to each device. Those two wires need to carry the entire current load for everything else. The POS lead from the battery (at the battery) should also have a circuit breaker in it to protect the main wire harness to the panel. I suggest you use 10 gauge wire between the battery and the switch panel.
 
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Re: wiring my boat lights - front and back only

ok i got my switches in. I rented a book from the library. best thing that i have ever done (read the instructions) kinda thing. It makes a lot of sense. I was shorting out because i ran the pos and the neg together and smoked the wires. Makes sense now. I was wondering how big of a fuse should i get from the battery to the switch? it has six switches but here is what i will be running on them: Bilge (already got it) front and rear lights, depth finder, spotlight, maybe a radio in the future. I was thinking a 30 watt fuse but should i go bigger? and also if i ran a 8 or 4 guage wire would that be too overkill? thanks again, John
 
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