just got my trolling motor in today.  now begins the process of trying to determine all that I need in order to hook this bad boy up.

minn kota terrova, 55lb thrust trolling motor, going on the bow of a Bonafide PWR.  Battery will be somewhere around 10ft away, towards the back.

 

I will be installing a 60a breaker per minn kota's recommendations.  On their site, they mention that the required wire size to use is:

Up to 5ft wire run: #8

5-10ft wire run: #4

10-15ft wire run: #2

 

A number of videos I've seen about installing these trolling motors, all mention using #8 wire.  I understand the wire size is determined by distance, but it seems like everyone is sticking to that #8 wire.

 

I'm really nervous about using the #8 since minn kota suggests #4/#2.  can anyone shed some light on this?  Is it best to stick with MK's suggestions on something like this? I have never installed or owned a trolling motor before.  this is all new to me

According to a search:

 

-A stranded 8 gauge copper wire has a current capacity of 40 amps in most standard applications"

-A 6-gauge stranded copper wire typically has a current capacity (ampacity) ranging from 55 to 65 amps. 

-A 4-gauge stranded copper wire typically has a current capacity of 85 to 100 amps.

-A 2-gauge stranded copper wire typically has a current capacity ranging from 115 to 130 amps

 

-A Minn Kota 55 lb thrust trolling motor typically has a maximum amp draw of 50 amps. This is consistent across several Minn Kota 55 lb thrust models like the PowerDrive, Terrova, Endura Max, and Edge series. A 60 amp circuit breaker is recommended for this motor, according to Minn Kota."

 

Thats where my mind was too. Id certainly be more comfortable using 4 gauge. Figured id ask before buying. 

 

Thanks for your input

Good luck.

 

I would run #4 for that length of a run. Whatever you decide to get, make sure it is copper wire, and not CCA (copper clad aluminum). The CCA stuff has a tendency to expand and contract under load, and starts breaking conductors, which in turn start arcing. 
 

For flexibility and overall quality, the best I have found is high end car stereo cable. Usually oxygen free copper and the tightest sealed insulation. Stereo shops will also have quality brass set screw type connectors. 

 

Ive heard to use marine grade, tinned copper wire. 

I would follow manufacturer’s recommendations to the letter at least until out of the warranty period.  

Here is a link to a wire size guide I always use.   

 

https://www.***.com/resources/1437

 

I would not go with 8 gauge.  It all comes down to how much voltage drop will you see in your wiring and are you willing to pay to reduce that voltage drop.  I did the math and at 50 amps I got 0.4 volt drop with 6 gauge and 0.25 volt drop with 4 gauge.  So are you willing to pay the extra money to run 4 gauge to get 0.15 more volts to the trolling motor.  That's a little than 1% less voltage to the motor and 1% more heat in the wire when you are running it at top speed.  I would think being in a kayak you would spend more time with the trolling motor on max than a boater so it might be worth the money to go with 4 gauge.  

 

I would go with tinned copper marine wire.  

 

 

 

 

 

Well, I think id prefer to stick with MK's suggested wire sizes. Certainly don't wanna cut corners.  Ill make a final determination tonight as to where my battery will be placed. Ill get wire size based off worse case. So if I ever wanted to move the battery forward or back, I have that option and the wire will already be in place.

 

So it'll either be a #2 or #4

well, I definitely want my battery in the back.  its roughly 12ft from the trolling motor.  So that makes the wire size needed, #2. 

Just to put things into prospective, a  $100,000 21 ft Ranger Comanche Z521R comes with 6 gauge wire installed at the factory.  Granted it comes with a 36V trolling motor so it can deliver 3 times the power with the same amount of current but it's still running around 50 amps at top speed.   

 

I get that bigger is always better but it's also thicker, stiffer,  heavier,  and more expensive.  I've never wired a kayak.  I don't know where you run the wire or how much space you have.  It's probably much easier than a bass boat.  Just know that the difference in performance between 2 gauge and 4 gauge will be minuscule and probably unnoticable. 

 

 

@Tennessee Boy - i understand voltage drop and how this all comes into play, but is any of this decided on the amount of heat that will be in the wire when running the trolling motor at top speed for a long amount of time? can running a #4 wire opposed to the #2 cause any damage to the trolling motor? if it's strictly a power source that's in question, then i'd agree with the #4.  that is certainly cheaper.

 

more help please - if i get a 50a receptacle for said trolling motor, those look to have #8 wire leads on them (both the receptacle and the plug).  Can you join a larger wire to the smaller without any issues?

Heat in the line is dangerous...it's the source of many boat fires. The more resistant a length of wire is, the more the power dissipates into heat...and that's the source of voltage drop. Won't damage the TM, but will be a source of concern. I'd run the largest diameter wire possible...if it suggests 2 gauge, then get 2 gauge. If it suggests 6 gauge...I'd run 4 gauge.

 

Yes, joining the larger main run to the smaller receptacle wire is not an issue, just make sure to use connectors that are rated for that joining.

3 hours ago, crankbait2009 said:

can running a #4 wire opposed to the #2 cause any damage to the trolling motor?

No.  Assuming you don’t wrap the wires in thick insulation to hold in the heat you are not going to start a fire running a 55 lb thrust trolling motor on 4 gauge wire.  
 

I would be much more concerned about making sure your connections are sound as far a safety is concerned.
 

I’m not saying you should not go with 2 gauge.  I just want you to understand your options.  I’m running a 24 volt 80 lb thrust Ultrex on the 6 gauge wire that was installed at the factory.  It works fine.  If they had offered the option to upgrade to 2 gauge for say $500 I would have done it.   Not because I need it but just so I would never have to think about wire size when buying a trolling motor in the future.  Running wire under the deck of bass boat is a pain.  You may want to go big the first time.  I don’t know all of the things you need to consider for a kayak.   If you can easily run the wire and having a big stiff wires in your kayak is not a problem then you might want to go with 2 gauge.  Running on high for a long time is something you might do in a kayak that I never do in my boat.  The current that a trolling motor pulls drop off quickly as you back off from the maximum speed.  On 7.5 my TM pulls half the current that it does on 10.  Minn Kota say the maximum current for my TM is 56 amp.  Every time I’ve checked it with an amp meter I get 41 amps.  So you really only need to be concerned when you’re running at 10 for a long time.

 

All of this stuff can be calculated to give you a good estimate of voltage drop and heat generation.  I’m not an electrical engineer but I did minor in engineering and took several EE courses.  The math required to figure out trolling motor wiring is electrical circuits 101.  😀

 

https://minnkota.johnsonoutdoors.com/us/support/trolling-motor-installation-guides/trolling-motor-wiring-and-battery-guide?srsltid=AfmBOootn2RQ4I_8y_38qv5-K2Hp6KPyo-E6_FQ9AgLeFVDykc8QXrua

 

The thing I overlooked at first when I extended my MK trolling motor wires was what the chart said. Not the total wire length, but the distance from the end of the factory wires to the batteries.

"NOTICE: Wire Extension Length refers to the distance from the batteries to the trolling motor leads. "

Wow. I saw the "extension" length too but assumed it was from the trolling motor to the battery. With that "extension", i come in at the 10ft range. Which lands me at the #4.

 

Even at West Marine prices, Ancor #4 AWG marine wire is only $2.79/ft. Your choice of red, black or yellow. The yellow is $1.98 on sale.

"Battery Cable by the Foot  Model # 179523 Mfg # 113512"

I made a 10’ extension with Anderson connections with awg #6.
Eight gauge is recommended by Newport for my 55# thrust trolling motor (60 amp breaker) and they actually sell a awg #8 in a kit for 5 and 10 foot extensions.

I believe the motors are wired with awg #12.

Have never had any issues.

@Motoboss

Off topic, do you have your Anderson plug mounted to your hull? If you do, mind posting a photo? Im trying to decide which outlet will be best for my set up. Ive been seeingseeinggandersons as well as the twist plugs. Curious how you have yours set up

56 minutes ago, crankbait2009 said:

@Motoboss

Off topic, do you have your Anderson plug mounted to your hull? If you do, mind posting a photo? Im trying to decide which outlet will be best for my set up. Ive been seeingseeinggandersons as well as the twist plugs. Curious how you have yours set up

No my connections are at the trolling motor end and at the battery. Here are the connections, just a 10’ extension to connect them which lays on the floor of my canoe.

This way I can have the battery next to the trolling motor if needed or have the battery up front for better balance.

 

 

 

Edit:

Heres the extension in the canoe floor. Most of it lays under the standing foam mat.

@Motoboss  I'm impressed.  👍

I just did mine last week with 6awg using Anderson sb50 connectors like shown above.  10ft extension from TM to battery. Tested it this weekend and it worked well.  I ran the Minn toka 55lb at full power for awhile and felt the wires and connectors and they were not even that warm.  

I ran mine yesterday at full power (with LifePo4 battery) for 20/25 minutes and not one hint of heat. Don’t like to run at full power for much longer than half an hour due to overheating the head unit, but never a concern for the wiring,

If you are running Minn Kotas you might want to read what they have to say about full power extended running.

Jig man do you have a link to that information?

 

I use a maximizer and can run wide open continuously all day and night with no problems until the batts die.

 

Its different on trolling motors with speed coils.