Need assistance in applying new knowledge into how-to

Discussion in 'OnBoard Electronics & Controls' started by Brylk1830, Apr 17, 2008.

  1. Brylk1830
    Joined: Mar 2008
    Posts: 30
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    Location: Wisconsin

    Brylk1830 Junior Member

    I hope you can bare with me, but i've taken it upon myself to learn the basics of electricity and how to create safe and proper wiring connections and I have a few basic questions for those who actually know what their doing :)

    I've been reading through the 12 volt bible for boats and have been studying and memorizing all the basic formulas but some of the more basic concepts seem to be evading me. For example, I understand if I wanted to hook up a 100 watt searchlight that I would need to measure the distance to/from the control panel, calculate the current, and then choose the appropriate wire size that's within the max voltage drop range, but what I don't understand is how the actual connections work.
    In my 16' bass boat at the moment I only have wires coming from the motor (alternator/solenoid i'm assuming) to the ignition throttle that is mounted on the side wall of the boat. All of this is connected to my 12 volt battery. From that same battery I have a red wire running to the fusee panel under the marine dash as well as a black ground that is also attached to the control panel. I've taken out all the old wiring that use to be attached to these for things like the lights/bilge/speedometer and plan on building an entirely new control panel where i can wire in new lights, etc.
    Now to the question, since I will want to install things like a radio and depth finder I am assuming I will need to use 2 batteries? And assuming I will need to do this, how can I connect the two batteries, or, can I just connect the deep cycle battery straight to the fuse panel and keep the ignition system seperate? Even more basic, when I want to connect something like the lights do I just need to connect the red wire of the load to a switch and then from the switch to the red bus bar and the black wire to the ground bus bar (I'm not sure yet what the difference is between a ground bus bar and what my panel currently is)? Also, since i'll need lights in the front and back will I just move over to the next free slot in the control panel and do the same thing? Basically, is this how I would create a parallel circuit and if not, I would appreciate just some basic how to advice relating to the actual connections of the wiring. Thanks for sticking with me through this initial learning fork in the road, and i appreciate any comments. Thanks-

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  2. marshmat
    Joined: Apr 2005
    Posts: 4,127
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    Location: Ontario

    marshmat Senior Member

    Hi Ken,

    I noticed you've aready asked a few questions about work you're doing on this boat. This is good. You've separated them out into reasonably specific questions in separate threads. This is very good.
    (You wouldn't believe how often we get something like "OK, so I got this 22' Bayliner for $300 but the stringers are spongy, the engine sorta cranks sometimes, and I wanna rewire it and put in a mahogany interior, how do I do it..." in a single question.)

    I think you are right to basically rip out the existing wiring and start fresh. Before you start buying wire and switches and stuff, sit down and make a list of all the gear you want to be running. Make note of how much current each thing draws and how long you want to run it for. Using this list, you can start drawing up a schematic of your new system and how it'll be wired. Then you can start sizing components and figuring out cable routes. It'll be a lot less frustrating with a bit of advance planning. It will make more sense when you draw it out on paper and can visually trace the current loops through your system.

    I think you're looking at a dual-battery system; one high-current starting battery for cranking the engine, and one massive deep-cycle to run everything else. There are dual-battery switches available to hook this type of system up, that are rated to be safe for this kind of current.

    Make sure to follow ABYC colour code guidelines for the new wiring. Red/black for everything is a Very Bad Idea in a boat; it's impossible to troubleshoot. The ABYC colour code is very helpful when it comes time to remember which wire goes where.

    Unless you are swiping components from an old British car, you'll be wiring negative-ground. In simplified form, the flow is as follows: (Battery +ve) > (Fuse panel) > (Switches) > (Devices) > (Negative bus bar) > (Battery -ve). Read and follow the guidelines in the book! 12VDC is a lot less likely to kill you than 120VAC, but can still do a hell of a lot of damage if you don't plan it out ahead of time.

    Best of luck, and we will be here to help you along :)
  3. dragonjbynight
    Joined: Apr 2008
    Posts: 129
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    Location: Indiana

    dragonjbynight Senior Member

    You shouldn't need two batteries as long as you are not drawing down more than the alternator can hold out on. The red and black wires that are coming from your battery to the original bus panel are your panel power and ground respectively. Depending on what you want to place in for the new bus, all your connections can be made from here. I personally like to have everything fused, with either in-line fuse or a fused bus.

    For example, your radio, you have power and a ground at your new bus, run a hot wire through an inline fuse, to the switch to the radio. the ground from the radio would go straight to the ground that goes to the battery and motor.

    Its basically the same thing as wiring in a car, but make sure you use marine rated wire.

    If you do a search of this forum, there have been many threads already started regarding this that you might find more helpful.
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