Trolling motor wiring

[lighthousehunter]

Hello, I realize there is a sticky for this, but the topic I need about basic boat wiring is missing the image pictures and diagrams. ( http://forums.iboats.com/forum/boat...iring-diagram-plus-navigation-switch?t=225399 )

I have a Salt water model Great white Motorguide (30-35 lbs thrust, I believe), and it's factory attached pigtail is cables of what I believe to be #10. The writing is kind of worn on it, as I bought the motor second-hand. I am going to run the positive (red) to a 50amp Motorguide breaker, which is the one recommended in the manual by the manufacturer, which will then continue as #8 marine wire to the deep-cycle marine battery. Reading other posts online, I read that #8 or #6 is best, so I was not entirely sure why Motorguide chose to use #10 for the pigtails... (I assume since it is cheaper...). Now my question, would I have a problem directly attaching the Neg cable to a battery? Or if I need to run a few more feet, can I use more #10 cable or do I need to up it to #8 even if it is only a short run? If so, how do I go about increasing the wire size inline? Do I use a terminal block for this? I should mention as well, the wire will be in "open air", I read enclosed wiring can cause more heating and thus carry less current.
Thanks for any help!
Mike McGuire

 

[NYBo]

How long is the run? Going with 8 versus 10 makes sense if it's more than a few feet, to reduce voltage drop.

 

[Silvertip]

MotorGuide used #10 wire for the motor pigtails because that's an appropriate size to handle the current draw imposed by the motor. Now that statement is true only if the motor is intended to be fitted with a plug and receptacle at the bow of the boat. They assume the boat wiring would take into account, the distance between the battery and mating receptacle. Normally, troller batteries are installed at the stern so a 16 foot boat would have a 32 foot total run which would require heavier wire to avoid voltage drop. Yes -- you can connect the negative cable directly to the battery. Changing the wire gauge (#8 to #10 for example) can typically be done with the appropriate size butt splice which is then protected with heat shrink tubing.

 

[lighthousehunter]

Thanks for the info! I have a 10' inflatable boat so the wiring is "temporary" but will always be in the same configuration. Originally, I was planning on having the battery in the stern, but I was considering moving it forward a few feet to better distribute the weight if possible. I am not 100% sure of the distance from the stern yet though...likely not more than 4 or 5 feet though. But if it is more than a few feet, I will run some heavier gauge #8 and try the butt splice for the neg cable.
Thanks again!
Mike