replacing some boat wiring

[RobDar]

When I bought my boat (tracker pro team 175), used, from a local marine dealer the trolling motor did not work, so they agrre to replace it with another used one they had about. The original was a 36 lbs thrust, the "new" one is a 50 lbs thrust. The wiring has not yet been upgraded between the battery and the motor... it is still the #10 30 amp wire and looks to not even be tinned marine wire or even high strand count wire (mtw etc)...it actually looks like run of the mill THHN wire. I am having heat problems on days when I have to use the trolling motor alot, not to mention that the increased resistance on the under sized wire is probably killing my battery life. Knowing that my 50 lbs 12 volt trolling motor draws about 50 amps at full throttle (motor thrust/system voltage x 12=amperage), I was going to use 60 amp #6 MTW cable and solve the copper corrosion problem with Pentrox brand anti-oxidant/dielectric compound. Anyone see a problem? Any suggestions on other types of wire? I would like to avoid paying the local marine dealer the insane prices they are charging for the "tinned type 3 #6 marine wire" ($42 for 25')

 

[jlinder]

Re: replacing some boat wiring

When sizing wire there are 2 factors to consider: How much current can the wire carry and not get hot, and what is the voltage drop in the wire. The first factor is safety, the second is concerned with getting you power to where you need it.<br /><br />The one measurement you need to determine voltage drop is distance. This is the length of the wire, battery to the motor, and back. Sounds like you have a 17 ft. boat, the wire run may be about 20 ft. each way, making it a 40 ft. run total.<br /><br />Try here for a caculator http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=22;t=001413#000000 <br /><br />6 ga. will give you a 10% voltage drop, or 1.2 volts. To get a 3% drop you need to go to 2 ga.<br /><br />Up to you. The larger wire will give you more thrust, or lower power draw for whatever thrust you pick. Up to you.

 

[Richard Petersen]

Re: replacing some boat wiring

Go to Walmart and ask for the LONG 18' to 20' HEAVY duty, only, jumper cables. They are fine strands and come up to 2 ga. Cut the clips off, lug the ends and your done for about $18.00. Great cables for trolling motors. I don't like the company, but the cables are great. Also change the trolling fuse to a 60 amp. fuse or C. B. from a auto supply place.

 

[jlinder]

Re: replacing some boat wiring

When I needed heavy cables I have gone to welding supply shops. Their welding cable is great for flexibility, and you can get whatever size you want.<br /><br />Just a thought