Got my new Motorguide TR109L yesterday. My wife, son and I installed it this afternoon.

It's a 36v motor. In the box was this wire with a 50 amp breaker......what's it used for with a 36v motor?

I already have breaker installed near my batteries.

Nothing in the manual about it.

In the owners manual (http://www.motorguide.com/userfiles/file/Support/OwnersManuals/2011%20Tour%20Manual.pdf) on page 11 it mentions installing it within 72" of the battery on the positive lead. If you boat already has a circuit breaker then you can skip this step. On pages 13-16 it shows it placed in the wiring diagram.  

You are correct.......but I have never recieved one in any of last 6 trolling motors that I have purchased.

I called Mercury/Motorguide today and the person I talked to or the 2 others he asked had ever seen/or heard of it shipping with a trolling motor.

Oh well.......guess I've got an extra.

I purchased the MotorGuide i3 45/45 last fall and no breaker was in the box as they recommend I buy theirs or equivalent.  I purchased an equivalent that mounts right to the battery post.  thanks for sharing that.

Wow! That's a nice looking cable!  I'll give you $500 for it.

I have a couple hanging in my garage that were included with Motor Guides. I have always used the one on my boat wiring harness that is just like it.