Battery Hookup Question

[catalanc]

Just purchased a Seaward 24 and purchased a solar panel. The outboard engine also has an alternator. SO .. when hooking up all this stuff, here is what I have done:
Engine wired directly to battery terminals
Solar panel directly wired to battery terminals (inline controller).
Boat circuits hooked up from battery; negative terminal to a negative buss. The positive terminal has a 30 amp fuse installed and then out to a circuit breaker distribution panel.
Three wires to each battery terminal, which is the max.
This sound about right?
thanks for the info.
carlos

 

[dlochner]

Almost. The wires attached to the battery terminals should be fused within 7 inches of the battery.

 

[catalanc]

Thanks for the reply, Dave. SO .. the 30 amp fuse to the distribution panel is affixed directly to the battery post. The solar panel goes through a controller and there is no fuse with the setup. I think that the engine has a fuse associated with it but I can't seem to locate it under the cowling. Add one inline close to the battery?

 

[dlochner]

Yes, the fuse protects the wire. If there is a fuse in the engine the wire from the battery to the engine is unprotected. Same with the solar panel controller. The fuse goes closest to the unregulated energy source, i.e., the battery. The small alternator on the OB and the Solar panel are limited in how much electricity they can put into the wire, the battery not so much. The battery can discharge a large current which can overload the wire and cause a fire or melt the insulation. A 100 watt solar panel can only put out about 10 amps at best easy to size a wire to handle that current. A battery can put out hundreds of amps.

For example, if the wire to alternator shorts out at the alternator all of the energy in the battery will flow through the wire to the short. The fuse needs to protect that wire. If he fuse is at the alternator all of the wire will overheat before the fuse blows, if it does. If the fuse is at the battery only the wire from the battery to fuse will overheat and then the fuse will blow. The rest of the wire will be safe. ABYC says fuse within 7 inches of the battery.

For a boat your size, a MRBF on the battery with a lead to a fuse block and then to the solar controller, alternator, and panel would work to protect everything.

 

[catalanc]

Ya, makes sense. I actually have a 30 amp MRBF on the positive battery terminal and could tie all three wires to it, not just the distribution panel.
Thanks again,
cec