Battery at one end of boat, elec. motor at other - wiring?

[-CN-]

Recently, with the addition of a small outboard motor on my 14 foot boat, I needed to balance some weight. I still use the transom mount trolling motor alongside the gas motor. And with the fuel tank and battery both back there as well, the back was just too heavy.

My bright idea was to relocate the battery to the front. Now the electric motor operates as if it is about to die - rarely has full power, and often times doesn't work at all. It will randomly die like there's no power source. When I planned this out, I set the battery up front and took the boat to a small lake near me with both motors installed, and I connected the trolling motor to the battery by running a set of jumper cables up to the front. I determined that the weight distribution with this configuration was the way to go, and I had no problems running either motor that day.

For the permanent installation, I was trying to find battery cable to extend the trolling motor leads to the front. I was completely put-off by the expense, so I hijacked the two wires out of a set of jumper cables and cut the clips off the ends and that's how I got my cables to run the power to the back to the motor. It is now that I have the motor issues. I checked all connections multiple times and nothing is loose.

Is the motor acting this way because of the distance the power is running? Or is it the wires I used? Anyone who relocated their battery, how did you do it?

 

[Al U Minium]

It was a good idea to re purpose the jumper cables. You can't skimp on the connections though. When you connect to the battery terminals they have to be shiny clean. How well the wire terminates in the battery connector is easy to accomplish. The best wire termination in a boat is a pressure (crimp) connector. If you buy a battery connector, get the correct size for the negative terminal and for the positive terminal. Do not waste your money on a universal fit connector as they are not worth a flip. When you splice the battery wires to the trolling motor, you will likely have ring lugs. Again, clean is the only way to go, use bolts with flat washers against the ring lug face and use one lock washer to keep the nut from vibrating loose. I recommend you use stretchy rubber self sealing tape to wrap the connections and finish with vinyl electrical tape. Stretch the tape as you apply and leave the last wrap free of stretch so it won't unravel later. Know that you have the equivalent of a high powered welder with this set up, the battery supplying enough power to burn a hole through your boat. So keep the battery unconnected until all your wiring is done. If you have good clean connections and the motor still doesn't like it, you can check to see if the wire is the problem by touching it. If the wire is warm that is energy not going to the motor and the cure is to get larger size wire. A good pick for this is #4 AWG and will likely be best priced at a welding store. The insulation on welding wire survives on boats very well. It has many strands of small wire making up the core which makes it very flexible and easy to mold to the wire run in your boat.

 

[richg99]

Not much to add after Al U Minium's well-worded post.

Sounds like you used too small of wire, or have poor connections, or both. Do what he said and you should be A-OK. You can burn out your trolling motor running the way you are, so you better fix it right, ASAP. richg99

 

[fishmonger]

Regardless of costs using under size cables will not work or will not work satisfactorily. This Conductor Gauge and Circuit Breaker Sizing Table is on the Minn-Kota site and I'm sure the numbers work for most TMs

https://www.minnkotamotors.com/Support/Battery-Selection---Rigging/

 

[-CN-]

Thanks. I'm going to rewire it with heavier wire. The stock TM cables appear to be about 12ga. I used 10ga cables. I'll try to find something like a 6ga even if it's heavy duty jumper cables again.

 

[JohnK]

https://www.skingco.com/wiresizechart

you will likely need to call the motor manufacturer to get the max amps, not the same as thrust

 

[Fire1386]

I did this with our smaller 14 foot boat to help with weight distribution. I used 8 gauge 20 feet long jumper cables which ran me $19.99....follow Minnkotas recommendations on connections and you should be fine.....

 

[-CN-]

I wanted to go fishing so I removed the outboard and remounted the trolling motor on the transom. I then put the battery in the back and connected the stock TM cables directly to it.
The stupid thing was acting up all day. Randomly no power, to very little power, and instant bursts of power. Mostly no power though. I checked the battery connection many times.
This is the same thing it was doing when I had it connected to a front battery. The TM appears to have an issue. It's a Minn Kota Endura C3 55lb bought brand new in July 2015. These are supposed to be almost bullet proof and should be running strong for many years even under hard use.
I've heard of batteries failing - it was also new in July 2015 - an EverStart 29 deep cycle from WalMart. Could this be a battery issue that I've been dealing with? It tests at 12 volts but I will tell you that it often takes way longer to charge than I think it should. Charging from around 50% to 100% will take overnight and into the next day. Where at other times, charging it from fully dead back to 100% only takes a few hours. I'm chasing way too many mysteries with this electric motor. I had to stop fishing so that I could row back from the other end of the lake.

 

[perchjerker]

when you say "it tests at 12 volts" how are you testing it?

 

[richg99]

I've had a nearly brand new (6 months old) battery go out. It had a bad cell and was replaced by the dealer at no charge. But, your issues sound even more like an intermittent connection.

I'd take the battery to an Auto Shack or one of the auto stores that will test a battery under LOAD for free. That may tell you something. Presume you've already shaken and pulled on every connection while she was running????

richg99

 

[-CN-]

when you say "it tests at 12 volts" how are you testing it?

The digital screen readout on my battery charger shows 12 volts when it's plugged in.
I had a bad car battery in an old car once. It was one of those cars where it wouldn't surprise me all that much to find something wrong. :LOL2: But it had a battery in it that was a year old, however, at random times it would drain completely and it left me stranded once. There was a "short" somewhere in the system. Tested the alternator and it was fine. A general check of the charging system would show "0", and then 5 seconds later show "12". Chalked it up to an unknown electrical issue in the car. Bought a spare battery to carry with me and swap into place if ever needed. I hooked that battery up and it was magically perfect again. When I took the battery in for my core fee refund, they tested it and it had a "short" in it.

 

[perchjerker]

ok thats not the correct way to test it. All that is telling you is what the voltage is running the depth finder

You need to use a load tester (or hydrometer if you have access to wet cells) to properly test the battery

but if its that old I would replace it

 

[-CN-]

ok thats not the correct way to test it. All that is telling you is what the voltage is running the depth finder

You need to use a load tester (or hydrometer if you have access to wet cells) to properly test the battery

but if its that old I would replace it

It was brand new 10 months ago.

 

[perchjerker]

I thought I read it was old. Then don't replace it I am the old one LOL

Sent from my SAMSUNG-SGH-I717 using Tapatalk

 

[dkhunter8383]

I would highly recommend genuinedealz.com for your battery cable. You can order any gauge wire and color by the foot, and they will also make custom cables for you. Last week I ordered battery cables for my trolling motor and cables to run to my fuse panel. All 8 gauge wire with the connections on each end heat shrinked in both black and red to keep everything straight. The custom cable only runs $1/foot and the connections cost next to nothing and are professionally assembled. Plus it is all marine wire

 

[-CN-]

Update to my situation.
The trolling motor was broken!
I did rewire the boat using 4ga wire, good crimp connectors, heat shrink, and tape. But now my motor is in the shop being repaired under warranty. There was water inside of it which was causing its problems. I can pick it up tomorrow and everything should work correctly.

 

[richg99]

Sounds like very good news. Keep us posted. richg99

 

[-CN-]

Going to my favorite electric-only lake only 5 miles from my house tonight!
Of course I'm taking the oars as well.
I'm really gonna pester the shop about what was all replaced, worried that there's damage done that will cause it to crap out permanently one week after the warranty expires. You can't just "clean it up", like the guy on the phone said he did, and expect electrical parts to be in proper working order for the long run. I really feel I'm owed a new motor, or at least a complete replacement of the lower unit.

 

[perchjerker]

what motor is it?

 

[-CN-]

what motor is it?

Minn Kota Endura C2 55lb 36". Purchased new from dealer in July 2015