Blown Fuses

[kybanker]

Hello everyone! I am pretty new here, and a novice, so I hope some of you might be able to help me. I have a 16ft Lund deep-v with a 20hp Yamaha 4 stroke motor.

I have installed navigation lights (both bow and stern lights) and wired them to a switch panel using 14 gauge wire. In addition, I added LED strip lights for the interior of the boat, and wired all of them to a switch panel. The back of the switch panel has all of the positive wires connected to it from the lights, and all of the negative wires from the lights are connected to a bus.

The bus has a positive side, and a negative side, and the top screw of each side of the bus is connected to a wire going to the battery. The positive wire going from the bus to the battery terminal contains a 7.5 amp fuse.

When this is hooked up to the battery, everything works fine. Today I hooked the motor up to the battery as well, and when it is connected, the 7.5 amp fuse keeps blowing.

Any ideas what would cause this?

Thanks in advance!

 

[gm280]

kybanker, you are not connecting the engine up through that same 7.5 amp fuse are you/ The engine should bypass that fuse and connect straight to the battery all by itself.

 

[G_Hipster]

It's not really clear. You only need one wire going to positive on the bus bar, but it needs to be of sufficient size to carry all of what the switch panel will carry and fused accordingly. The fact it only does it when the engine is hooked up has me thinking the charging system/ rectifier needs checked out.

 

[GA_Boater]

Just to double check - Are you positive the battery positive is connected to the positive buss bar? I would ask about the the other side of the battery, but I want to stay positive. :smile:

Is the fuse blowing when starting in the motor or as soon as the motor is connected to the battery?

 

[kybanker]

No Title

Hi guys, thank you for your responses. To answer your questions...

1. gm280: As you can see in the photo below, the wires from the bus go right to the battery terminals, as do the wires from the engine. They are separate, and touch together only on the terminals.

2. G_Hipster: I don't believe there is much draw from the switch panel. It only has a rear navigation pole style light, a bow navigation light, and LED strips. When the engine is not hooked up, this all runs from the battery without a problem.

3. GA_Boater: Thanks for the positive vibes; I need them right now! I am getting frustrated! I did make sure that all of the wiring was going to the proper terminals.

I have attached a few photos which I hope will help clarify (it is difficult to articulate all of this). The first photo shows the bus and switch panel from the rear, and you can see the wires on the top of the bus which run to the battery. The second photo shows the wiring from the bus leading to the battery. You will note that these are two "Battery Tender" charging wires. I put these on so that I could easily unhook the battery and plug in a trickle charger this winter (this is a duck hunting boat). The third photo shows the connection when I have the motor hooked up, as well as the wiring to the bus. Finally, the last picture shows all of the lights working fine when the motor is not connected.

Thanks again for any ideas. It appears having the engine hooked up to the battery is what is causing the problem, as after I disconnected it, and replaced the fuse, everything works fine.

 

[G_Hipster]

Thanks again for any ideas. It appears having the engine hooked up to the battery is what is causing the problem, as after I disconnected it, and replaced the fuse, everything works fine.

That's why I'm thinking the problem is on the engine side of things. Inadvertently crossed the battery terminals or some wires along the way? I've had a bad rectifier blow fuses as you describe. Sounds like you have the circuit you installed ironed out.

 

[alldodge]

As GM mentioned your running all your circuits from the battery using a 7.5 amp fuse. Using 14 gauge wire to feed the circuits means you should be able to use a 15 amp fuse. Maybe need to step back and look at again. You should have IMO at least 12 gauge (20 amp) feeding your bus bars, 10 gauge (30 amp) is best for future use. Once at the bus bar then branch out to your other circuits. Here is a basic setup

 

[gm280]

kybanker, I am still unsure what your real problem is. So I drew up a little pictorial to help me figure this out. Look at the actuarial and tel me if that is how you have everything wired. And if so, are you telling me that when you connect the engine up to the battery, it blows that 7.5 amp fuse? And if that is also correct, does it blow that fuse as soon as you connect the engine up or after you try to start the engine?

 

[Fed]

You could have a Positive short circuit from your added in wiring to the hull, BUT the hull is NOT grounded to the battery Negative UNTIL you connect the motor.