Boat rewiring advice?

[Ryno78]

Originally Posted by REW

Ryno,
I have several questions on your overall boat layout.
1. You indicate that you are running a Lund Alaskan with a 40hp tiller.
2. Do you ever fish from the bow of the boat, or do you do all of your fishing from the stern of the boat?
3. Do you have any electronics in the bow of the boat?

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Furthermore, I really don't see the need or reason to split up your boats loads as you indicate.
If you install a group 31 battery in the stern of your boat, it will easily take care of all of your starting motor needs, as well as all of the needs of your electronics, pumps and lights.

If you also have a trolling motor battery - fine - just run the trolling motor from the trolling motor battery.

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If you only have a single fishing station with all depthfinders and gps at the stern of the boat, and all of the pump controls at the stern of the boat, I would wire the boat as follows:

1. I would wire the two heavy motor wires to the group 31 starting battery.
2. I would then connect a 30 amp circuit breaker to the + terminal of the battery and run an 8 gauge wire from the circuit breaker to a 6 or 8 fuse box - preferably with surface mounted fuses.
3. Then, run an 8 gauge ground wire from the - terminal of the group 31 starting battery to the ground lug side of the fuse block.
4. Then, for all of the electronics and pumps, I would simply run 16 gauge wire from each fuse to each pump switch and then to each pump. Or run 16 gauge from each fuse to each piece of electronics.

You could also run either 14 or 16 gauge wire from the light fuse block to the light switch and then on to the lights. I assume that you will have a standard light switch that will allow you to run the single white stern light or the combo bow and stern light at the same time.

The key part of this entire discussion is to only have 4 wires on your starting battery. Two heavy motor wires and two 8 gauge wires to your fuse block.

After you complete all of your wiring, be sure to use a good quantity of plastic tie wraps to have a nice secure non flapping wire harness custom made for your boat.

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Now, if you do have a bow fishing station with separate bow electronics or a need for separate pump controls, you can do the same thing.

i.e. simply run a pair of 10 gauge wires from your stern fuse block to a bow fuse block. Then, just run short wires from the bow fuse block to any electronics that you might have situated in the bow of the boat.

Again, at the end of the day, you still only have 4 wires connected to your group 31 starting battery and the two heavy trolling motor wires connected to your trolling motor battery.

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I have wired up many boats using this concept and both the concept and the implementation of this method works for a very nice compact, clean and very operational electrical system.


Take care
REW

REW – Thanks for the reply. During my research I ran across a lot of your posts which were VERY helpful. Thanks! Can you tell me what you mean by “heavy motor wires”? Is this a specific type of wire?
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Answers to your questions: I do fish from the bow and have a trolling motor and power anchor up there on a 12 volt deep cycle bow battery. I plan on adding a bow mount deptfinder which I was going to wire to the forward hatch battery instead of the bow battery to avoid interference issues.

My current setup is this: bow trolling motor and anchor are connected to a bow battery without any circuit protection, so I need to fix that, and my depthfinder, navigation lights, bilge, power trim, and engine are all connected to a group 29 battery in the stern. The previous owner of my boat used inline glass fuses for the navigation lights and bilge. Nothing has gone wrong yet (which actually makes me reluctant to mess with things!) but I wanted to get away from inline glass fuses (following some of your advice there!).

The reason I was going to split the boat loads up is because I’ve read and been told that I should try to minimize connections to the cranking battery to minimize potential for depthfinders, lights, etc. draining the cranking battery to the point that it won’t turn the engine over. So I was going to add a third battery into the mix and dedicate all “accessories” to this battery. To me, this would give me some peace of mind that my cranking battery won’t be drained by my accessories.

So the setup I was considering would be 1) bow battery connected directly (with circuit breakers) to trolling motor and power anchor; 2) forward hatch battery to power depth finders (currently 1 but I plan on adding a second), standard navigation lights (stern white light and bow combo), bilge pump, and potentially some LED convenience lights; and 3) stern battery for engine cranking and power trim.

I do like your approach for minimizing wires to the starting battery, and would prefer to run two batteries instead of three. Am I just being paranoid by thinking that my accessories would run my battery down too much to crank the engine?

Thanks very much for the advice!

Ryan

[Ryno78]

REW - I reread your post and realize that by "heavy motor wires" you meant the wires running from my tiller motor! My bad...

[REW]

Ryan,
Rather than installing a 3rd battery, just install a permenant set of jumper wires, or carry a set of jumper wires to start your engine from the trolling motor battery if the case ever happens when your main motor has expired.

It is just good boating to carry a set of jumper wires anyway.

On my boat, I made the jumper wires permenant. All of my boats batteries are in the same stern location. As a result, I simply made a heavy negative jumper wire that was run from the negative of the starting battery to the negative of one of my trolling motor batteries.

I also made a 2nd + jumper wire that is long enough to go from my starting battery to the + terminal of the trolling motor battery that has the negative jumper connected. But, I simply connect both ends of the + jumper wire to the same + terminal of the trolling motor battery to avoid shorting anything out.

If the case occurs that I need to jump my cranking battery, I unscrew the nut from my trolling motor + terminal, remove one end of the jumper wire and retighten the nut. Then, I remove the + terminal nut on my starting battery, drop on the jumper wire and tighten the nut.

I start the main motor and finish the day of fishing.

When I return home, I restore the jumper to its stored position and then charge all of the batteries.

Good luck
REW

[REW]

Ryan,
After reading your reply, I would connect your trolling motor and power anchor to the front trolling motor battery.
I would connect everything else to the cranking battery through an appropriate fuse block at the rear drivers area. Don't put any other fuses in the lines between your rear fuse block and your lights and or front electronics.
There is nothing wrong with running everything off of your cranking battery. About 90% of the boats on the water do this.

Generally speaking, interference is normally NOT picked up through the power leads. Rather, it is picked up in the form of air transmissions of signal that are picked up by the electronics as a function of the electronics sensitivity.

For example, most of todays trolling motors use a chopper style power supply. When the chopper style power supply is supplying partial power to the trolling motor, the power supply acts as a miniature radio transmitter and can effectively screw up electronics readings. It is not because any interference is coming through power lines - rather it is because it is an air borne signal that is coming into the electronics from the air through the case of the electronics and resulting in interference.

The same thing is true with AM radio operation and DC brush style pumps running. i.e. bilge and livewell pumps.
When DC brush style pumps run, the brushes spark and generates many different electrical frequencies of interference. That is why, if you are listening to an AM radio and need to hear it - you normally need to leave all of your DC brush style pumps turned off. Again, the interference is coming through the air.

Take care
REW

[nicko]

Originally Posted by Ryno78

Hawker:
I was going to get the Blue Sea Systems 6 circuit fuse block rated for 30 amps. I haven't worked through the total max amp draw because my boat is in storage and I don't have all the details related to bilge model, etc. However, I was going to rig the fuse box to include three 3 amp fuses (stern depth finder, standard navigation lights, + one extra spot for the bow depth finder I plan on adding), two 5 amp fuses (bilge pump + one extra spot), and one open spot. I've looked at various bilge pumps on line and think a 5 amp will cover me and I'm confident that the 3 amp fuses will be sufficient for the lights and depthfinders.

So in total I think I'm looking at a max of 15 amps. Thanks for the voltage drop calculator! I'll give it a shot.

Ryan

Ryan,

Sorry for the delayed response, here goes.

Blue Sea Systems makes nice panels. I'd use part # 5025 or #5030. AWG 8 gauge to battery. I also used a 30amp fuse right at the battery before going to the panel. This protects against the odd chance that you get a chafing of the cable somewhere. here is the link for the fuse holder:

http://www.littelfuse.com/data/en/Data_Sheets/FHA.pdf

I would not wire your graphs through this panel. Graphs are very sensitive to voltage fluctuations and interference. Run them separately. I use a single #10 AWG to battery and then split to bow and console. I fuse it at the battery using a waterproof blade fuse holder (above) big enough for both locations simultaneously. Place a waterproof connector like this at the battery so you can pull power from graphs totally if you want.

http://terminalsupplyco.com/Store/Pr...px?pc=12015799

I use these for every connection on my boat. They are weatherproof and easy to install by hand. As said above, look at your amperage requirements. Most of what you have takes very little. Bilge pumps and live well pumps are pretty light and you could easily use a #14 AWG. I don't use anything under #14. unless it's very short runs. Voltage drops on small gauge wire at distance so I keep small gauge wire for short 2-3 foot runs.

Other than that, also use heat shrink tubing con all connections and solder as many as you can. This will insure that they are moisture free and vibration resistant. Those are the 2 big issues with boat electrics.

I also use wire loom for everything. Be very careful running wire through holes and around corners. Wire will be subject to lots of vibration and the chances of it cutting the insulation are pretty good. Thats why I use wire loom or convoluted tubing. You can buy it at any hardware store or radio shack. Cheap insurance and it makes you r install look professional.

here are links for the tubing:

http://www.radioshack.com/product/in...ductId=2103809

It comes in sizes from 1/4" to 3".

Good luck......

[Ryno78]

REW & nicko:

Thanks very much for taking the time to offer up some great advice. I really appreciate it. I think I've got a plan that will get my wiring situation squared away. Thanks again and tight lines guys.

Ryan

[Raybob]

Originally Posted by Ryno78

REW & nicko:

Thanks very much for taking the time to offer up some great advice. I really appreciate it. I think I've got a plan that will get my wiring situation squared away. Thanks again and tight lines guys.

Ryan

I agree!

Other than that, also use heat shrink tubing con all connections and solder as many as you can. This will insure that they are moisture free and vibration resistant. Those are the 2 big issues with boat electrics.

I also use wire loom for everything. Be very careful running wire through holes and around corners. Wire will be subject to lots of vibration and the chances of it cutting the insulation are pretty good. Thats why I use wire loom or convoluted tubing. You can buy it at any hardware store or radio shack. Cheap insurance and it makes you r install look professional.