Can I use a 6V battery to slow down TM?

[wasabi_VA]

I'm using a regular 12V (40 lb. thrust) trolling motor on a small boat. The lowest setting moves the boat too fast. I don't want to drag a bucket or anything. I'm fishing small ponds so don't need to run very far or need to run the motor very much. Can I use a 6V motor to send half the voltage to the motor, thus slowing it down?

[cart7t]

Some TM's won't even turn with only 6volts applied.  

[DADto4]

Some TM's won't even turn with only 6volts applied.

Even if it did work I would be suspect to causing damage to the motor over a extended period of time. My opinion.

You should talk to sneaker he had a post in July about "trolling motor basics" and seems knowledgable on the subject.

www.bassresource.com/bass_fishing_forums/YaBB.pl?num=1215535988/all - 103k -

[Ann-Marie]

It depends on how your speed control works.  If it is electronic it may need more than 6 volts for the electronics to work.  But it can't do any harm to try.  Trolling motors cannot be sold that would self destruct on a low battery voltage which is a common condition when batteries run down so try it.

[Jig Man]

If that doesn't work and the tmotor is a tiller, you might run the boat the other way and use reverse to slow down.  I used to do that with a jon.

[sneaker]

Sounds like you have a 4-5 speed motor and a standard prop. These motors can operate with any voltage up to their rated maximum, in your case 12 v. So the 6 volt battery is OK. Trolling a crappie jig is slow work, and even if you could slow the prop to the desired speed, your boat would be very sensitive to wind speed and direction. Dragging a bucket (or sea anchor) would allow you to have much better speed control when going that slow. If you can live with the reduced maximum speed using 6 volt battery, you will get twice the trolling time that you would get using 12 volt battery of the same physical size . If you have other electrical equipment on the boat (bilge pump, fish finder ect.) be sure they can live with the 6 volt power.

[wasabi_VA]

is there a device I can install to reduce the voltage to 6 volts so I can continue to use my trolling motor battery? Basically I am wanting to do what the manufacturer has already done with the 5 speed rheostat they have installed to give me 6 speeds. This rheostat provides different voltage levels to the motor depending on the setting I choose. All I need to do is get a similar rheostat and wire it into my trolling motor lead. Then, if I ever want the full voltage I set my new rheostat to full (or a setting of 5) and let the full voltage pass. I wish I could find a 2 or 3 setting rheostat like this. I can wire it up into a cheap radio shack control box.

[Fishing Rhino]

Here's a sure fire way to slow down the speed of your trolling by using a 6 volt battery.

Tie it to a line, and toss it off the stern.

Sorry for the levity.  It popped into my mind.  The devil made me do it.

[Wayne P.]

Adapting a smaller prop to fit your motor may solve your speed concerns.

[wasabi_VA]

Wayne,

I looked at the other motorguide prop that would fit my motor - it takes a 3.5" - and mine is a 3 blade and the other is a 2 blade. The motorguide info says the 2 blade is for higher performance. So I can't tell if the 3 blade is faster or slower... what do you think?

[Wayne P.]

PM sent

[Ann-Marie]

is there a device I can install to reduce the voltage to 6 volts so I can continue to use my trolling motor battery? Basically I am wanting to do what the manufacturer has already done with the 5 speed rheostat they have installed to give me 6 speeds. This rheostat provides different voltage levels to the motor depending on the setting I choose. All I need to do is get a similar rheostat and wire it into my trolling motor lead. Then, if I ever want the full voltage I set my new rheostat to full (or a setting of 5) and let the full voltage pass. I wish I could find a 2 or 3 setting rheostat like this. I can wire it up into a cheap radio shack control box.

If it is a simple series rheostat it should be possible to add another FIXED resistor in series and provide a switch across it. The switch would become a high/low range switch and the existing speed control would work for each range.  

To determine what size resistor you need, measure the Resistance of the speed control when set on the lowest speed setting.

You then need to purchase a resistor with this ohms that is big enough to handle the current.

See if you can measure how much current the motor draws IN THE WATER on the lowest speed. The wattage you need for the new resistor is amps x amps x ohms. Example if it draws 5 amps on low speed now, and the resistance measured at 4 ohms, you would need a 100 Watt resistor.

Then wire it in series with the speed 12 volts going to the motor and put a switch in parallel with it to short it out for HIGH range.  With the switch on LOW range (off), full speed on your control would be equal to the lowest speed you have now and go down from there until it doesn't run at all.

[Way2slow]

MinnKota used to make a Maximizer that connected to the battery and you connected your standard five speed TM to it.  This gave you full variable speed just like the didital motors and you could turn the prop just as slow as you wanted.   I still have mine I bought 30 years ago and wouldn't take anything for it, best thing going for your situation, that's why I bought it.  If you can find one that works, get it.

Your TM doesn't not use a variable resistor, they control the speed through the motor windings.  You will see there are a bunch of wires on the switch going into the shaft down to the motor motor.