What trolling motor wire gauge do I need?

Discussion in 'Vehicles, Boats, Campers, & ATVs' started by DuckLn, Feb 27, 2013.

  1. DuckLn

    DuckLn Well-Known Member

    So i received a Minn Kota maxxum 55 lb 12 V trolling motor and the wire leads coming from the motor are 10 gauge per the "10 AWG" imprinted on the wire so my first instinct was to get 10 gauge bonded tinned "marine" wire. There is nothing in the paperwork that says what gauge wire should be used but instead says to consult the American Boat and Yacht Council which I did and found nothing. But after searching another forum and googling and all that it looks like a toss-up between 6 and 8 but then I come back to the 10 gauge lead already on the motor from the factory which would be the weakest link. I need to pull it about 17 feet total if that helps any experts determine proper size and also I'll mention that there is nothing is the paperwork that mentions "maximum amp draw" although it does provide a recommended circuit breaker of 60 amps. Thanks for any help.
     
  2. UCNE

    UCNE Well-Known Member

    10 gauge will work fine..........
     

  3. jhw

    jhw Well-Known Member

    Since you will be running it 17ft., I would go with the 6 gauge. You will lose some power, going 17ft with 10 gauge wire.
     
  4. js05_14

    js05_14 Well-Known Member

    6 gauge should work but be sure to use a 60 amp breaker. I sure would have guessed that the motor leads would be 8 gauge. My old minn kota 40lb. and my new 55lb. both have 8 gauge leads. My trolling motor wiring in my boat is only 8 gauge and I bet I will have to go to 6 AWG wire with the 55lb. motor if I'm going to run on the high speeds for any amount of time. There is a formula for figuring wire size based on voltage drop. I will see if I can find it.
     
  5. lineman2002

    lineman2002 Well-Known Member

    I've got a 55 Minn Kota and I've got it wired with 10 gauge with no problems
     
  6. Buck-Ridge

    Buck-Ridge Well-Known Member

    Install #6 for that size motor unless you want to pay for 55 pounds thrust and only get 35 or 40. I have looked this up before and posted it. I have 6 in my boat for a smaller motor. 10 is too small the length of the boat 8 is marginal. DC amperage increases rapidly with distance. You will enjoy better battery life and the full power of your motor if you use big enough wire.
     
  7. DuckLn

    DuckLn Well-Known Member

    The only hurdle with the 6 gauge (other than it may be too large in diameter to fit in the accessory rail) is that the Marinco 3 prong plug I bot ($30) is good for 8 to 10 gauge. You can purchase an optional ($24) 6 gauge adapter which I don't mind using but I'm still curious about the lead wires on the motor being 10 gauge and thus reducing the "flow" or amps or volts or whatever its supposed to be called and void my reasoning for buying the 6.
     
  8. QCDually5.9

    QCDually5.9 Super Member<br>Forum Sponsor

    The 10 ga. On the motor is good BUT for that length. You COULD use 10ga all the way back but as already stated, you would lose an amount of current and thrust. Go with the 6 if you can. Think about it in this way. You are wanting to "feed" that 10ga with a supply line at least as big. But due to the length you are running, a larger supply wire would be best.
     
  9. Saltydog

    Saltydog Well-Known Member

    can you put a battery up front, closer to the motor?
    If so, you could feed it with a lighter gauge wire without losing voltage.... since you won't have all that resistance loss of a long run.
     
  10. DuckLn

    DuckLn Well-Known Member

    Battery is staying in rear.
     
  11. js05_14

    js05_14 Well-Known Member

    I'm assuming that you have to run 17 feet of wire from the battery to the motor so that is the total distance one way. 34 feet would be your total circuit length. I believe that the max amp draw for a 55lb. thrust minn kota is 46 amps. If that is the case, than using the voltage drop formula with 8 gauge wire gets you a drop of .98 volts over that distance with a total drop of 8.18%. 6 gauge wire gets you .62 volts dropped for a 5.14% total drop. Minn kota says that your voltage drop has to be less than one. I not positive on the figure myself but I have read that a trolling motor needs a 5% or less voltage drop to run efficiently. Based on that, the 6 AWG wire will get you right at the 5% total drop so it should be sufficient to run your new motor wide open without causing problems.

    Voltage Drop = 2 x 1 way lenth of circuit x resistance x current / 1000

    8 AWG resistance is .6282
    6 AWG resistance is .3951
     
    Last edited: Feb 28, 2013
  12. DuckLn

    DuckLn Well-Known Member

  13. js05_14

    js05_14 Well-Known Member

    I have seen that chart as well on their website. I have also seen where people have called their customer service and their default answer is 6 AWG for situations similar to yours. I'm sure they like to spec. overkill so if there is problems they can hopefully eliminate user wiring error and not waste time with looking at a product that is actually working fine. The link you provided does show that the allowable voltage drop is 5%. If you can confirm that your motor draws 46 amps max then my calculations above show that 6 AWG will get you to the allowed 5% total voltage drop.
     
    Last edited: Feb 28, 2013
  14. Buck-Ridge

    Buck-Ridge Well-Known Member

    Looking at the bluewater link I posted it looks like 4 also. Use the recommended wire buy an extra foot for each leg and you'll have enough to redo the ends a few times and never have to replace it.
     
  15. DuckLn

    DuckLn Well-Known Member

    Just got this back from Minn Kota customer service:

    Clayton,

    Thank you for your recent purchase of the Minn Kota brand. The max amp draw for your motor is 50amps. If you want to extend your leeds 16ft I would suggest a 6 guage wire with a 60amp breaker.

    Best Regards,

    Tim
     
  16. Wes Ramsey

    Wes Ramsey Well-Known Member

    Good luck finding 6ga wire though. I went to every store I could think of in Conway that carries wire, and the only places that had any were the car stereo joints, and they wanted something like $4-5/ft. I ended up buying a set of decent 4ga jumper cables, snipped the clamps off and soldered new ends on for the battery and TM leads. Works like a charm and was WAY cheaper than buying 6ga wire.
     
  17. js05_14

    js05_14 Well-Known Member

    A good place to get your wire from is a website called genuinedealz. I just priced 30 feet total of red and black 6 AWG marine (tinned copper wire and shrink wrapped tinned copper connectors) cables built to my specifications for $45 shipped. That is not much more expensive if any more than tracking down 6 gauge non marine wire locally and getting the proper crimps put on the connectors. Once you get past 10 gauge you need some special tools to get the proper crimps.
     
  18. That is the first thing I thought of as well. Sometimes you just have to think outside the box...
     
  19. t-bone

    t-bone Well-Known Member

    I just ran 6 ga wire for my trolling motor. I bought it from gregsmarinewiresupply.com.