Battery/Breaker/Fuse need?

[johnlaqua]

Hi everyone,

about to buy my first tin and mod it up, but wondering what to expect for batteries and overall electrical work (what all i would need for best efficency)

would be running probably not much bigger than a 50lb thrust tm, preferably two trolling motors eventually but id only start out with one until funds allowed two, the normal operating lights incase i run into the dark, thought about some led interior lights just for added visibility inside the boat, and eventually a stereo, maybe....

so how would i decide on how many batteries to run, whether or not id need fuses or a breaker switch or both (seems to be a lot of debate on that issue) dont really know much about electricity, want to get all my ducks in a row so i know what to expect when i start.

thanks for all the help and suggestions anyone gives me

 

[Bob Landry]

You didn't say if you jhave an outboard for power or if you are going to depend on the trolling motor for mobility as well as trolling. If you have an outboard, go for a day and see if the one battery handles it. If not then you can always add a second batery, but that's extra weight and less is better.

I would look at a small Blue Sea fuse box. it will allow you to add devices as desired, but on a small tin, your electrical needs are going to be minimal. The wire supplying the fuse/switch panel needs to be fused as close to the battery as possible. Actually, I prefer a resettable circuit breaker over fuses, as you don't have to worry about getting caught without a spare if it trips. The trolling motor will run directly connected to the battery and also needs to be fused(50A). I used 8ga wire to feed my fuse block, 16ga for the running lights, and 14ga for the VHF radio which you probably won't have.
Connect fish finders directly to the fuse block as a switch may screw up any shutdown sequence that it may have.

 

[richg99]

You will need a BREAKER (not a fuse..you probably couldn't find one big enough) for the trolling motor. The manufacturer should have the size in their specs, if not...call them.

Probably 40 50 or even 60 amp breaker. Put the right size in...too small...it will blow too often. Too large...won't blow when it should....and could cause a fire in case of a short circuit.

It should be mounted as close to the battery as possible. Many are mounted on the battery itself, with the TM wires running from the breaker on the positive side.

To find out what size wires you need, use this gauge, or many similar on the net...or search this site for one. https://boatstuff.awardspace.com/awgcalc.html

Yes, you will need a fuse for every electrical item. Your Fishfinder will need one, your lights should have one, your horn, etc. etc. To find out the right size, you have to determine how may amps each item will draw when the item is turned on.

I'm sure more guys, with a lot more experience in installing boating electrical systems, will pipe in soon. regards, Rich

 

[jojo]

I agree on a CB over a fuse, but there are big enough fuses for trolling motors.

 

[FishAllDay]

Probably a stupid question, but why is a breaker needed with a trolling motor connected to a battery? I have a 40# thrust motor directly connected to my battery with the standard clips that trolling motors come with and have never needed or thought about a breaker..Am i missing something?

 

[Loggerhead Mike]

In your case if something shorts out you can jerk the clips off the battery terminals. If your motor is hard wired to the battery you need some kind of protection ( cb )

 

[FerrisBueller]

There's always a chance of something going wrong and it could fry your TM motor, and having a breaker would protect it, and only pop the breaker. It's a $30-$40 investment to save your TM. It's always a good idea to break/fuse any electronics just to be safe

 

[richg99]

Fishallday..I am guilty of the same arrangement on my trolling-motor equipped kayak.

As was said, I can pull the clips off if I noticed something happening.

That won't do me much good if, some how, the wires get jammed and partially cut. What will probably happen then is that the wire insulation will melt; short out; spark and maybe set something else on fire.

Your trolling motor isn't what is being protected..the wires powering your trolling motor are what is being protected..from melting and causing a true issue...as it might on a boat. The wire protection is why the fuse/circuit breaker is normally recommended to be close to the battery, not to the trolling motor.

Unfortunately, many of us do things on a boat that wouldn't pass a home-owner's inspection, even though we know we shouldn't.

regards, Rich