Basic 12V system for my 14ft tinny

Hey folks.

Brand new to the site and I am hoping for a little assistance. Last summer I was fortunate enough to be able to get a great deal on my very first boat - a 14 ft Lund SSV- and although it has no bells or whistles I have enjoyed every minute on it. I am now slowly starting to add some toys, with the first being a fishfinder I was given for Christmas and eventually I am planning to install a bilge pump and some nav lights.

I have very limited experience with electrical circuits, but have done some research and came up with the attached diagram and would very much appreciate any advice.



I do have a couple of questions to add:

1. Would anyone recommend a battery switch for such a simple system?
2. Do I have the right sized fuse connected next to the battery?
3. What guage wire is recommended for each connection?

I would like to keep it as simple as possible, and since my outboard is a manual start I don't need to include it in the equation at all. When I can finally get a trolling motor, I plan on having its own dedicated battery.

Thanks, and I'm looking forward to your input.

Looks good for the most part.

A battery switch wont do you much good at this point, because of the simplicity of your proposed setup. As long as you remember to turn off all accessories, you should be fine.

The fuse you have between the distribution and the battery is fine, however I recommend using one of these:
https://www.bluesea.com/products/5025/ST_Blade_Fuse_Block_-_6_Circuits_with_Negative_Bus_and_Cover
This will simplify your setup, allow you to individually fuse each circuit (which is absolutely necessary,) and looks really nice!

The size of wire will depend on how long the run is. 16-18 gauge should be fine to go from the distribution to the accessories, and maybe use 14 gauge for the bilge pump. I like to use this wiring chart when determining wire size. https://www.hitmanhotrods.com/en/admin/sources/editor/assets/chartsGraphs/wire_sizing_chart2_titled_filled.jpg

If you need any more information don't hesitate to ask!

Most FF's call for a 3amp fuse, a 5 will work ok, but nothing over 5 to protect the FF from any surges that might occur. If you use the individually fused power center, just insert the correct size fuze for each connection, and good to go. You could just pull the main fuse to make sure every thing is "off" when you get back home instead of switches.

mbweimar said:

I recommend using one of these:
https://www.bluesea.com/products/5025/ST_Blade_Fuse_Block_-_6_Circuits_with_Negative_Bus_and_Cover
This will simplify your setup, allow you to individually fuse each circuit (which is absolutely necessary,) and looks really nice!

Click to expand...

Hmmm...I will seriously consider that fuse block. Thanks!

mbweimar said:

Looks good for the most part.

A battery switch wont do you much good at this point, because of the simplicity of your proposed setup. As long as you remember to turn off all accessories, you should be fine.

The fuse you have between the distribution and the battery is fine, however I recommend using one of these:
https://www.bluesea.com/products/5025/ST_Blade_Fuse_Block_-_6_Circuits_with_Negative_Bus_and_Cover
This will simplify your setup, allow you to individually fuse each circuit (which is absolutely necessary,) and looks really nice!

The size of wire will depend on how long the run is. 16-18 gauge should be fine to go from the distribution to the accessories, and maybe use 14 gauge for the bilge pump. I like to use this wiring chart when determining wire size. https://www.hitmanhotrods.com/en/admin/sources/editor/assets/chartsGraphs/wire_sizing_chart2_titled_filled.jpg

If you need any more information don't hesitate to ask!

Click to expand...

Now that the winter's done and I'll be starting this soon, I do have one last question regarding wire size - What size should I use from the battery terminals to the fuse block? Also, is there a specific type of ring terminal to use for this connection in particular? BTW, I did end up getting that exact fuse block you suggested!

Thanks again...maybe I'll post pics soon

I would also look into getting float switch for your bilge. Then you can wire it to go on with the toggle switch or if something happens and you take on water then will automatically start pumping it out. It really helps if you get caught in a down pour or you launch your boat and forget to put the plug in. Ask me how I know!

Again, it depends on how long the run is. Of only a couple feet, ID use 10 gauge. That will be overkill, but in case you want to add an accessory plug, or flood lights, or stereo later, it'll be big enough to support that. #10 ring terminals with the heat shrink on them is the way to go.

mbweimar said:

The size of wire will depend on how long the run is. I like to use this wiring chart when determining wire size. https://www.hitmanhotrods.com/en/admin/sources/editor/assets/chartsGraphs/wire_sizing_chart2_titled_filled.jpg

Click to expand...

Great chart and has been shown on here in various forms a few times, just make SURE TO USE THE LENGTH of both the pos & neg runs, so if the loads are 6' from the battery, you would determine the wire needed for that total amperage needed (plus add for overhead) for a 12' run. Most people forget that part, to double the 1-way run length.

ajax_anglr said:

I do have one last question regarding wire size - What size should I use from the battery terminals to the fuse block? Also, is there a specific type of ring terminal to use for this connection in particular?

Click to expand...

Add up the amp load of everything you're using, plus allow some for expansion and then determine the length.

If using an item, like a spotlight that is rated in watts, use the formula of Watts / 12.6 VDC (nominal voltage) = Amps. So a 55-watt light would be a 5-amp load. Some electrical items (starters, actuators, trim tabs, etc.) have a peak starting amp draw that is much higher than their continuous amp draw, but not so much for the items you're likely to add.

I believe 10 AWG would be fine for your run and I prefer good marine quality adhesive-lined ring terminals.

Thanks for all the great advice...can't wait to get started.

going to be running a fish finder, maybe a little stereo in my 14' Lund. What do people use to keep battery juice going while out? Solar charger of some sort?

Here's the aforementioned chart - BE SURE TO DOUBLE THE LENGTH OF THE WIRE RUN WHEN USING THIS. IE you serpentine a wire from your fuse block along the backside of the bench seat then up the side of the boat across to the middle of the bow bench then forward to the bow light it may only be 8' from the block to the bow but you've run a wire 12' long to connect to the bow and you need to base that wire size on a circuit 24' long in this chart.

tna0066 said:

going to be running a fish finder, maybe a little stereo in my 14' Lund. What do people use to keep battery juice going while out? Solar charger of some sort?

Click to expand...

You'd be surprised how big a solar panel you'd need to recharge a deep cycle battery - unless you have someplace you can mount a 4x4 panel where it will receive full sun you're going to have a hard time reliably recharging a battery after draining it with a trolling motor & stereo (FF hardly draws anything). Plan on connecting to some sort of charger (onboard, basic 12v wall plugin battery charger etc.)