New Member, trolling motor wiring upgrades Help Please

[PT175SE]

Hello, forum members, I am a new member of the forums and have purchased my first boat this past October 2011. It is a 2005 PT175 Special Edition with a 50 hp Merc 2 cycle with 11 hours on the motor, the boat looks like it has been in the water only a few times as this thing looks brand new. It was a deal that I could not pass up. We haven't even taken it out to the lake as there was a few upgrades I wanted to do over the winter.

I have reading the forums for quite a while now and have learned a lot about boating from the members. I have planned to upgrade the trolling motor as most of the lakes in Illinois that we will be fishing at are electric only.

When reading the threads about trolling motor upgrades most all of you say upgrade to a 24volt variable speed and I should upgrade the wiring also to 6ga.

I spoke to a local Bass tracker boat dealer this past Friday and he told me that they upgrade the trolling motors from 12 to 24 volt on new and used boats all of the time and they do not upgrade the wiring, they only upgrade the plug and keep the same 50 amp breaker. He also told me that most of their upgrades are for the 24 volt 80lb thrust trolling motors. I looked at a new Bass Tracker 175 and the trolling motor wires are 8ga.

I am confused; can someone please tell me why I would need to upgrade the wires on my boat? I don't want to make a mistake and ruin my new trolling motor because of improper wiring.

If I have to update the wiring can I use 6ga. Underground water proof wiring?

I am looking to purchase the Minnkota 70lb or 80lb trolling 3 new optima batteries and a new plug.

Thank you for your time and patience with these questions.
Doug

[oldjim]

If you look at American standards 6GA max is 37 amps, 8GA is 24 amps. Size wire to handle max map draw for your TM. Undersize wire or close to undersize will heat and you will loose some TM speed and endurance, as batteries are drawn down faster. I personally would not use a 50 amp breaker if i was only going to draw 25-30 amps. You run risk of over heating and burning up TM. When a motor gets weeds on it it will exceed current draw numbers and run it long enough and it will get hot enough to burn brushes and seals. My skeeter with fortex 80 has 40 amp breaker 6GA wire.
Oldjim

[-Joe-]

If you look at American standards 6GA max is 37 amps, 8GA is 24 amps.

Not real sure where this data came from but even worse case scenario, 6 AWG with a TW or UF rated insulation in raceway, cable, or buried underground and using worse case terminals rated for 60°C, the rating is 55 amps and 40 amps for #8AWG. Considering it will be run it whats considered 'free air' the amp rating goes up to 80amp and 60 amp. {NEMA 2011Table (B)(16)&(17)}.
Now that being said, you wouldn't want more breaker rating than wire or motor rating. If you were upgrading to a 101 or 109 thrust TM I would say upsize wire to #6. A 80lb TM will never pull more than the rating of the #8 wire unless shorted out then thats were the breaker would kick out.

[oldjim]

Joe
amp data is from (AWG) standards. If you buy wire in us it will be marked with a AWG code indicating size ie 6ga. most places selling wire will have awg table showing amprage recommended for wire size. AWG charts are available on web at numerious locations, just search AWG amps draw.
Oldjim

[-Joe-]

I fully understand AWG wiring sizing. I simply didn't understand where you got the ampacities that you listed. Below is a copy of my 2011 NEC code book. I also did as you suggested and did a quick search of #6 AWG ampacity and this is the first link I came to. Granted I don't by my wire and cable from Grainger I simply used it as a reference to the Ampacity of the wire. My only question of your post was the numbers you showed were way low of its actual capability.

http://www.grainger.com/Grainger/Building-THHN-Wire-3ZK49

[oldjim]

Not my intention to offend any one my data come from this web page. http://www.powerstream.com/Wire_Size.htm
Please note the following.
Thnn or thnm wire is not suitable in a marine application. Insulation is to thin and not flexible enough for marine env.
The table you are referring to is max load before melt down not recommended wire GA. for 24v marine applications.
Both MinnKoda and motor guide recommend #6GA wire for motors drawing 37 amps.Both say so on there web sites.
The above web site will show recommended AWG wire size. Please bear in mine that this is wet env. and for a TM you want to minimize voltage drop so length of run is also a factor.
Nec codes do not apply to this marine low voltage env.
That's all I have to say, sorry if I offended you.
Oldjim

[-Joe-]

Jim,
You haven't offended anyone. Hope I haven't done so either. I just wanted to clarify the numbers  you posted. From looking at the chart from your website reference, I'm going to guess your a lineman? Am I correct? The 37 amps listed in "Maximum amps for power transmission" Column is in reference to Transmission feeds from power plant to sub-station. Power Transmission Defintition:Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to electrical substations located near demand centers. Completely different monsters than Secondary wirting and DC wiring. THHW and any wiring with thermo-palstic or PVC insulation is suitable for wet locations.

[fishman400]

PT175SE:

I have upgraded my TM with a Minn-Kota Maxxum 70# thrust 24V system.  I too was concerned with upgrading wire until I read the TM's instructions that came with the TM.  It recommended a 50A breaker and it had a wire size chart in it.  I've had no issues with heat or anything.  Keep in mind, most people wont be running their TM at full power for 5 hours straight.  I have run my at full power for 15 mins when I first installed it to see if the wires were hot and everything was cool to the touch.  The wires coming out of the foot pedal on the TM are 8ga anyways, so I wasnt too worried about upgrading.   Wouldnt hurt anything by upgrading, but this was my 2 cents.  I did upgrade the plug to a Minn-Kota plug and upgraded to a sealed resetable breaker.   

[Creel Limit Zero]

Max Amp draw on a Minnkota 70 is 42 amps I believe...

Voltage loss for 8 Ga wire at 42 Amps is .02688/ft.  It is recommended you have less than 1 Volt loss in the whole system.  So diving the 1 Volt loss / .02688 voltage loss per foot, you can have a system of 37.2 feet.  That leaves you 15 foot of wire between the battery's and the plug, with another 3 foot of wire from the Plug to the Trolling motor.  As (15 ft + 3 ft) X 2 = 36 feet of wire.  Although I'm pretty sure Minnkota/Motorguide only say the Voltage loss up to the plug be under 1, not including the wire on the TM already...  That being said, you could have 18 feet of wire up to the plug. 

As always, the less voltage loss the better.  If you had a 6 Ga wire instead of an 8, you would be able to have almost 1/2 the Voltage loss for the same length of wire...

[JayPea2006]

I spoke to a local Bass tracker boat dealer this past Friday and he told me that they upgrade the trolling motors from 12 to 24 volt on new and used boats all of the time and they do not upgrade the wiring, they only upgrade the plug and keep the same 50 amp breaker. He also told me that most of their upgrades are for the 24 volt 80lb thrust trolling motors. I looked at a new Bass Tracker 175 and the trolling motor wires are 8ga.

I upgraded to 24v and didn't replace the wiring and that was 3 years ago. Only problem I've had and only a couple times, was tripping the breaker when I had it up on high speed and kept it running for 5 minutes straight.

I have the exact same model, year, and HP as you do. You'll love it, but make sure to follow through on upgrading the TM to 24v or you'll have an aggrivating time trying to hold that light boat in a breeze with 12v.

[cubsfan02449]

I'm planning on installing a 24V minn kota 70 maxuum. i dont plan to replace wires but will go to a 40 amp resetable breaker. Im a little confused on the plug and receptical. What plug does the minn kota maxuum come with? 2 hole? 3 hole? I have a 2 hole plug on my 2011 txw which came stock with the cheesy Motorguide 12v 46lb bow mount. Im assuming the minn kota wont plug right in. thinking of buying this from bass pro:
http://www.basspro.com/Marinco-ConnectPro-Plug/Receptacle-Kit-for-Trolling-Motors/product/23099/134760
Id imagine Ill have to cut the minn kota wire which runs from the foot pedal and plugs into the receptical just before the plug and insert the marino plug then take out the stock receptical and install the marinco receptical. Is this correct?
   
Also thinking of buying 2 optima blue tops: 27M is the model number. $200 a piece is pretty expensive though. Anyone have any experience with these, is there a cheaper but still quality option out there? 
Thanks for any help!

[RushFan]

If you're getting your TM from BPS the sales person should be able to direct you to the correct female connector.  They did at my BPS and glad he did as I didn't think about it.  BTW I have a 2009 175TXW Tracker and the 12v was not suitable for my purposes.  Went with a Motorguide 75 ProSeries.  Chose it as the bracket was the same, less to mess with!!!  I have experienced the breaker tripping if I'm on the highest setting for about 10 or 15 minutes.  Not a usual operating condition for me.  I am this year looking to upgrade to 6 gauge wire.

[fishman400]

Cubsfan, you are correct about having to.cut the wires from the foot pedal and running them into the marinco plug. The reason there are 3 "holes" is for a 12/24 volt system. You wire one pin to ground, one to.the 12v system and one to the 24v system. Some trolling motors have a switch to choose BTW 12 or 24 volts. The reason you have to get a new receptacle is that the wires from the motor guide are sealed in the receptacle.

Also, I would have liked to get optima batteries, but Im cheap and don't wanna pay that kind of money. I went with Walmarts everstart deep cycles (group 27 size) and they were only $68 a piece. I've had them for a few months now and I've had no problems with em. I've run for 8 hrs in heavy wind and still had plenty of power at the end of the day. Sure optimas are better and lighter, but thats too much money for me!!!

[cubsfan02449]

Thanks for the great info guys. RushFan that is a good point about the Motorguide having the same bracket. Im not too excited about drilling holes in the bow with the Minn Kota.



These are a couple questions i emailed Minn Kota customer service: (They got back to me the next day, pretty nice.)

I have a 50 amp breaker now. is a 40 amp breaker needed? Will the 8 guage wires be ok? Do i need to purchase my own plug and receptacle?

Thank you for your email. An 8 gauge wire will work just fine with that trolling motor. The Maxxum 70 when on high speed will draw 42 amps, so we would recommend using a 50 amp breaker. Our trolling motors do not come with a plug installed on them, that would be something that you would have to install based on your individual application.
This is the plug that we offer, which is made for us by Marinco. The plug we sell is the plug and receptacle.
http://store.minnkotamotors.com/dyn_prodlist.php?k=418633

[fishman400]

Definitely measure your existing holds.before you drill! The maxxum mount has multilple holes and should bolt directly to the MG holes. My maxxum fit perfectly to the the MG holes and I was happy to not have to drill any more holes.

[cubsfan02449]

Thanks fishman. That is great news that it should line right up.

I have a question about the 3 wires:
I obviously now have only 2 wires a neg and pos that run from the 12V deep cycle battery up the boat to the receptical. Im assuming i have to run another 8 guage wire to the front of the boat to the Marinco receptacle (terminal #3). This would be the wire attached to the positive terminal on battery 1; the highest voltage wire. This isnt the postive wire on battery 2 that has the jumper attached correct?

Also, im assuming 3 wires come out of the minn kota foot pedal and will run into the marinco plug is this correct?
Attached to this post is a detailed pdf i found on Marinco's site and understand how this should be wired if 3 wires do come out of the foot pedal.

Thanks for your help

[attachment outdated - deleted by admin]

[BassBUFF]

The MK should have 2 wires coming from the foot pedal and you'll use Fig 2 of the Marinco diagram. Let us know how the install goes!

[cubsfan02449]

thanks bassbuff.
i assumed it should only have two. What would the purpose of fig 4 in the marinco pdf be for? Also notice how theres only 2 wires connected to the receptacle in fig 3.

i will let you know how the install goes. hope to have installed in a week.

[Creel Limit Zero]

Fig. 4 is if you have a switch on your Trolling motor to go from 12V to 24V.  If you have it on 12V, it will only pull power from the battery closest to the plug in the figure.  If you switch it to 24V, it will pull power from both battery's.  This is done by picking which wire they are pulling positive current from.  Hope this makes sense. 

[cubsfan02449]

Thanks a lot. Makes sense now, shoud've read fishman's above post a little more carefully.

[cubsfan02449]

Got the trolling motor installed. The maxxum mount didnt line up so holes had to be drilled. Ended up taking the 9 screws out of the carpeted aluminium piece where the plug and trim switch panel mounts to. go to this link for pic:  http://i1162.photobucket.com/albums/q530/cubsfan02449/feb079.jpg
Removing this provided lot's of room to reach the rubber T's which held in the old motorguide. Mounted the maxxum mount first to the existing 2 rubber T's (closest to the carpeted aluminium piece or middle of bow). Then drilled guide holes in the other 4 holes up the mount towards where the prop lays when stowed. Took off the mount and drilled through bow. Then re installed. For the 4 screws not being mounted to the T's put a washer on and then lock nut and tightened. Marinco plug and receptacle was an easy install. http://i1162.photobucket.com/albums/q530/cubsfan02449/feb076.jpg

Ordered an extra narrow battery tray so have 3 trays in battery compartment. Had to saw off extra plastic screw holes (middle 4 holes on each tray) to get them to both fit. Decided to mount trays parrallel rather than horizontal to aviod wires and livewell pump. http://i1162.photobucket.com/albums/q530/cubsfan02449/feb078.jpg
Wired the battery's in series and to my liking the minn kota prop spun. 

Having a little trouble understanding how to wire up the batteries so all 3 will charge at the same time. I know i can attach the charger wires to the + and - of 1st trolling motor battery and the other charger wires (which were on the cranking battery before install) to the other trolling motor battery to charge them up. but is it possible to charge all 3 with the stock Guest on board charger?

[BassBUFF]

If the charger is a 2 bank version it's not going to charge all 3. Cheapest answer is to get a portable one just for the cranking battery .

[cubsfan02449]

yes its a 2 bank charger. I will probably do just that. Is leaving the jumper wire attached to the 2 trolling motor battery's alright while charging?

[BassBUFF]

Yes, the charger will see them as 2 seperate batteries.

[cubsfan02449]

ok. thanks a lot for all the help. spring fishing cant get here soon enough.