Electronic speed control for trolling motor DIY

I am working on this and want a reverse. Will it work if I add a double pole double throw switch after the speed control to switch polarity to the motor? Will it hurt the motor?
 
Thread starter #22
The module comes with a SPDT switch to reverse direction: FWD-OFF-REV. You don't want a switch on the main power leads because the back-EMF of the motor will quickly ruin the switch contacts from arcing. The motor will be fine but the switch will wear quickly.
 
Thread starter #23
Not to mention a DPDT switch that can handle 50A will be an expensive monster!
 
The module comes with a SPDT switch to reverse direction: FWD-OFF-REV. You don't want a switch on the main power leads because the back-EMF of the motor will quickly ruin the switch contacts from arcing. The motor will be fine but the switch will wear quickly.
The speed control module I have only goes one way.

I really just need the speed control going forward. But I do want reverse too.

Will I see any I’ll effects if I put the switch in front of the speed control and only have the variable speed on the forward wires?
 
Thread starter #25
In general, you cannot reverse the input power to the module - that may fry it. In any case, the input power is the same as the motor power, so there is no advantage.
 
The upper diagram bypasses the speed control entirely
in one position.

The lower diagram would work, but for price of switch
that could handle the amperage, you'd be better off
just getting another $15 module that's designed/comes
with a reversing switch---which will be an inexpensively
replaceable switch, when it inevitably croaks from salt
exposure.
 
Thread starter #29
Ya know, if you throttled all the way down or turned off before switching, which is not really a terribly restrictive requirement, you wouldn't have the arcing, but you still need a switch/relay that can handle the DC motor current, not to mention have lugs that can accept #10 AWG wire. I don't have time to look at that relay, as I am off to Oconee in the early AM, but if you think it will work, go for it. As long as the end result performs, who's to say what's right or wrong?
 
Ya know, if you throttled all the way down or turned off before switching, which is not really a terribly restrictive requirement, you wouldn't have the arcing, but you still need a switch/relay that can handle the DC motor current, not to mention have lugs that can accept #10 AWG wire. I don't have time to look at that relay, as I am off to Oconee in the early AM, but if you think it will work, go for it. As long as the end result performs, who's to say what's right or wrong?
Thanks for answering my questions. Based on you screen name I assume you are an engineer? Are you an EE?
 
RamblinWreck, your posts and details on the components and usage are terrific. While waiting I have a question and a couple tips? to share.

Question: I don't have the controller yet but am wondering if it is possible to separate the pot from the other components of the controller? I'll be using it in a Gheenoe where I will be moving around more than in my Tarpon 10. I envision a 1) pot and another on-off switch in a small container located nearby the operator that is 2) separated by a nice length of coiled small gauge wiring from 3) the remainder of the controller with its heavier wiring which would be housed in a second container located in a safe place near the battery.

Tip? A friend has a diy controller on his Outback. He grew tired of having to readjust the pot after turning the pot to off when he wanted to coast and then back on when he wanted to resume. He modified it by installed a separate on-off switch in the circuit which turned the TM off. When he wanted to resume he merely turned this switch back on. Since he didn't touch the pot the TM returned to its previous setting. He said this made it much easier to maintain a desired trolling speed.

Tip? 2 I bought a DC 6.5-100V, 0-100 amp LCD digital multimeter that displays volts, amps, watts and watt-hours. Mine carried the Drok label but Mictuning and others sell the same thing on Amazon. It costs $17 and they are China's best small hard to read delicate instruments. I'm using it to determine the energy used by my TM at various speed settings. I ran tests in the water and recorded data for speed settings 1, 3, and 5. I then transferred the data to a simple a simple spreadsheet where I can input the expected minutes of operation at various speed settings for the lakes I fish and it would calculate the watt hours of energy used. This proved helpful to get a sense of the battery capacity needed.

As a decades ago electronic project enthusiast I got a hardy chuckle out of your comment "Part of the thrill of electronics projects is the first power up." Soo true.
 
Thread starter #33
Comments:
1) The pot is already on a short ribbon cable, so you can extend it and remote mount it as you wish. You don't have to use the on/off switch in the pot, you can move those 2 wires to a separate switch, or just use the fwd/off/rev switch. Since I have a chartplotter/FF on the yak, I use the GPS to show the speed for trolling, usually 0.8 MPH when long-lining jigs for crappie.

2) It is not very accurate to try to estimate battery charge by the voltage. I just fish and find out by doing it how long it lasts. My new Ionic lithium battery is 50 Ah, runs my trolling motor 2 days without a charge, and has a Bluetooth phone app that shows you all the data: voltage, current, temp, and remaining charge % on my iPhone. Plus it only weighs 15 lbs, compared to 45 lbs for a 35 Ah AGM deep cycle mobility batt I was using, that would barely make it thru one day. Expensive but worth it IMO.
 
You can extend the wires for the pot. That is what I did.

You can also add a switch to turn it on and off.

I also used two Bosch style relays and made an h bridge(I think that is what it’s called) so i would have forward and reverse.

420232C1-C995-49D7-AAC2-8595C05D0694.jpeg
 
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Hi....I guess I can see if one keeps varying the speed (or DC current) may be tough on TM. So, is that why TM was only designed to keep at 5 speeds instead of variable to ensure the TM don't breakdown? Why is the new TM all put emphasis on having the digital maximizer aka. variable speed?

order pcb
 
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Hi....I guess I can see if one keeps varying the speed (or DC current) may be tough on TM. So, is that why TM was only designed to keep at 5 speeds instead of variable to ensure the TM don't breakdown? Why is the new TM all put emphasis on having the digital maximizer aka. variable speed?
as I understand it the 5 speed motors are cheaper to build and super simple but less efficient at lower speeds.

The variable speed motors have PWM controllers which make them more efficient but they need a circuit board to control pulses. As the circuit boards got cheaper more people started using them.

The next thing will be brushless motors.
 

weagle

Senior Member
Cool. I need to do this to my Kayak trolling motor. I undid the head on the motor and just extended the wires back to a box by my seat. Somehow that caused it to go from 5 forward and 3 reverse to 2 forward and 1 reverse.
 
Thread starter #38
There are two low-Ohm speed coils that act as resistors, and the (twist) rotary wafer switch connects them and the motor leads in various ways to create the 5F/3R speeds. It is very cheaply constructed and probably got out of "time" in the move, or something. With the controller, you only use the 2 wires that go to the motor, and tape off the rest.
 
Thread starter #39
UPDATE Aug 13, 2020 :

Well, the trolling motor stopped working yesterday for some reason. Of course I was way down Lathem by the creek and had to paddle all the way back, while a thunderstorm was threatening.

Today I tested the speed control and all was as it should be. The motor Ohm reading was intermittent, so I took apart the motor (Newport NV series 46 lb thrust). The entire motor and commutator area was full of water. The main bearing was corroded along with everything else, and one brush/spring was damaged. So the motor is toast. It lasted barely a month out of the 2-year warranty. It was used heavily, but not abused.

h2o_damage.jpg

Not sure if it is even worth the trouble to try and rebuild it. The good news is this is a cheap motor (@ $180); the bad news is it only lasted 2 years.
 
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Thread starter #40
Stay tuned. Newport had me fill out a warranty claim, so we'll see what they can do. It is obvious from the amount of corrosion that this has been an issue since before the warranty expired July 15, so they said to fill out a claim and attach pics. So we'll see how it goes. In the meantime I cleaned it up - The rotor Ohms out, and I think with a new brush assembly and some extra sealant I might be able to fix it, however, the commutator is pretty scarred up, so it would just eat up the brushes in a few months. Here's hoping NV makes it right.
 
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