12vdc marine fuse panel wiring help please


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Old 12-22-07, 06:17 PM
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Question 12vdc marine fuse panel wiring help please

Hi newbie here. I have a 12vdc marine fuse panel/switched with a cigarette lighter and 2 switch battery tester. First I don't know if the black or red is hot and second it has two longer red wires coming from the batter tester switch and I am not sure where they go.

Also has extra fuse beside the lighter with red wire coming from it........where does it go.

Anyone know a link to all purpose dc wiring guide?
 
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Old 12-22-07, 06:25 PM
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The black wire is the ground, and the red wire is the 12 volt positive wire.

I do not understand what you mean by "2 switch battery tester." A tester usually has a positive and a negative terminal. Get them backwards and the meter goes the wrong way. A switch (unless it has a light or something else that needs power) has no concept of positive or negative.
 
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Old 12-22-07, 09:40 PM
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Please give more details on what you are doing. What's your current setup and what are you changing? I would look at the electrical section of automotive books and/or basic electronics wiring. That may help you with what you are doing. Usually with DC the wires are referred to as positive which is also stated as + and is usually a red wire; and negative, which is - and is usually the black wire, and is usually connected to the chassis/frame, and is also referred to as the ground. Although 12v usually doesn't have the risk of shocking you, you still need to treat the circuits with respect. Batteries have acid in them, and it is possible for them to explode. Automotive/Marine batteries are able to produce a few hundred amps, which can quickly cause a fire and/or battery explosion. Be sure that all your circuits are fused, and never short the terminals on the battery. You can get burned, as shorted wires heat quickly. It is easy to overload a battery or circuit because the voltage is low, it takes more current (about 10 times) compared to household AC voltages. Disconnect the negative battery terminal when doing any work. Unlike AC where the electricity changes direction, DC current only flows in one direction. This is important when connecting electronics. If you connect them backwards, you could fry them (some better electronics protect against this). Motors will spin the opposite direction if you switch the wires. Finally, automotive batteries like to be fully charged at all times, but not overcharged.
 
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Old 12-23-07, 05:47 AM
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Poorly-wired marine electrical systems can be more dangerous than bad house wiring because you can't just walk away from a fire if you're on the water, and a spark can easily ignite the fuel or cause an explosion.

This book is a good one.
 
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Old 12-23-07, 07:07 AM
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Originally Posted by Miriam C.
Hi newbie here. I have a 12vdc marine fuse panel/switched with a cigarette lighter and 2 switch battery tester. First I don't know if the black or red is hot and second it has two longer red wires coming from the batter tester switch and I am not sure where they go.

Also has extra fuse beside the lighter with red wire coming from it........where does it go.

Anyone know a link to all purpose dc wiring guide?
The cigarette lighter you speak of.. unless it actually has a lighter in it, is really a 12 volt accessory recepticle. the small red fused wire is the hot for that and gets connected to one of the 2 positive battery connection feeds at the main switch disconnect (Off 1 2 all/both)

Black is the ground wire /Neg battery connection

The 2 longer switched reds are the connections for the positives of the two batteries. One red to each positive feeds on your batteries when switched, will show you the state of each battery.

The negatives are all interconnected on the system.
 

Last edited by brewaholic; 12-23-07 at 07:43 AM.
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Old 12-23-07, 09:43 AM
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not the same as yours, but will give others an Idea of what a 2 switched battery tester looks like.



let's make this more clear

The cigarette lighter you speak of.. unless it actually has a lighter in it, is really a 12 volt accessory recepticle. the small red fused wire is the hot for that and gets connected to the load side feeder of the main switch disconnect (Off 1 2 all/both) this way the lighter will only work when your main switch is "on"

Black is the ground wire /Neg battery connection

The 2 longer switched reds are the connections for the positives of the two batteries.
One red wire (1 side of switch) goes to one positive feed terminal on your number 1 battery the other red (2 side of switch) wire goes to the positive feed terminal to number 2 battery. When switched to either 1 or 2 will show you the state of that battery.

The negatives are all interconnected on the system.
 

Last edited by brewaholic; 12-23-07 at 11:41 AM.
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Old 12-24-07, 06:20 AM
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Although the two long red wires connect to the positive battery terminals, they are not power feeds! They are only used to check the condition of the batteries. Do not use them to power any devices.

If I seem overly cautious it's because I've seen some tragedies over the years.
 
 

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