Battery Connection Brain Dump ?
 

Having a brain dump connecting my battery in boat.

I had removed the battery from the boat over the winter.
I did take notes how the battery connections were made, so I would remember when connecting in the Spring

Simple right.... not rocket science!
BIG Red cable connects to the Main Positive terminal.
BIG Black cable connects to the Main Negative terminal.

Well I have multiple other wires also attaching to BLACK main cable.
(Bilge, live-well Aerator, etc) through a series of connections apparently tied together.

The BIG red main cable, I also have a black wire attached to it with electrical tape, but cannot remember why? Haven't traced that black wire back to source yet.

Question now is, what is that black wire that is attached to the red main Positive ? I didn't connect that black wire to Positive terminal for fear of creating a short circuit ?

Also, I have a green wire in battery box which has never been connected to anything since I purchased the boat. Green wire looks like it has an in-line fuse holder ? Could this possible be for the live-well aerators?

Anyway connected the Main red to Positive, Main Black to Negative and the boat started no problems, just trying to figure out some of the other wires?

Thoughts?

The black wire on the red cable might be for the bilge pump. Green is usually a bonding wire and should connect to the negative terminal.

Found an old Post I made on same questions back in 2013 and response from DaveR, will use that as guidelines.

DaveR you're always there, excuse the pun, 'bail me out' ! :)

You stated "The black wire on the red cable might be for the bilge pump"...
Would that be attached to the Positive terminal ?

Also, what do you mean by a 'bonding wire ' ? Never heard that term?

Trace the black wire, if possible. If that proves impossible, check for continuity between it and the negative terminal. If there is no dead short to the negative terminal, touch it to the positive terminal and see if it makes a big spark. If no big spark, it's probably supposed to be connected to the positive terminal. This would be a good time to mark it...

Bonding wires are used to tie all the metal that touches water to the negative battery terminal in boats. It's important to keep all the metal at the same electrical potential to help prevent galvanic corrosion. Green or green and yellow wires are typically used for bonding.

Those cell phone cams are great, when you figure it out, snap a pic for next year. :)

tape
 

Or better yet, get some black and some red electrical tape and tape the wires together with the appropriate color once you've got it figured out.

Is it normal to see an inline fuse on a bonding wire?

NO, it isn't !