Will 18 volts damage a 12 volt trolling motor?

There you go....

130ah of lead acid provides something like 70ah ( peukert effect ) x 12v = 840 wh

vs the 36wh of thedewalt pack ( assuming 2ah, i don't know what pack you actually have )
 
The new 18 volt ion phosphate batteries @ 2.4 amp hours & weigh 1.5 lbs. Right now I have the 18 volt XRP which I'm going to start replacing with the 18 volt ion.
 
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The new 18 volt ion phosphate batteries @ 2.4 amp hours & weigh 1.5 lbs...
So, it's 43 watt hours.

A 46 pound thrust minnekota motor will pull between 30 and 40 amps when full-out, so, even IF you could efficiently drop the 18V down to 12, you would have power to run the motor for about 5 minutes, maybe less. And that current draw would likely melt the innards of the battery.

I would strongly recommend that you get a 12V deep-discharge battery for that motor.

But, here's the other question... why are you using a 46 pound thrust trolling motor on a kayak? A 25 pound motor would work very well, as a kayak (or a canoe) has a very low drag hull and there's little wind resistance. The larger thrust motors aren't going to take any faster than a lower output motor; the motor RPM is essentially the same, the main difference in output thrust is the prop size. And, the larger motor is less efficient than a smaller one when used on a smaller boat. The larger motor would accelerate the kayak faster than a smaller motor would, but, that's about it. Under the same conditions of speed, battery, wind, and boat, a smaller motor will run longer than a larger motor.

The controllers do pass the current; on the minnekota, they pulse the full 12V power to the motor rapidly. They vary the width of the pulse to vary the power. Since the power is either on or off, the losses are low, and the controller is lightweight.

On a standard controller though, the power isn't pulsed, and in these cases, there's little difference in power consumption between full output and partial output - the excess power is just dumped as heat.
 
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I have done this many times with voltages up to 50V on Minn Kota 12V as well as other trolling brands.

Here are some facts.

* You will get a very noticeable performance increase as you increase voltage
* You will get a corresponding reliability decrease in many cases

I had the most luck using Golf Cart Speed Controllers. These are set up to take about 24V - 60V as input ("48V Lead") and they will give you an output that is 0% to 100% duty cycle. They are rated to push hundreds of amps continuous... so these loads are nothing for them.

* 25% Throttle, Nominal 12V
* 50% Throttle, Double Voltage on motor, holds pretty well
* 100% Throttle, Screaming -> Burst Only!!!

You can only run a 12V Trolling motor for 30 seconds or a minute under 48V Burst configuration. I have had them fail in all manners - but - when you are trying to get into harbor in a swell you wont really care if it wrecks your motor... if it gets you past the rocks and into calm water.

Failure: Wires Melted Together

Ironically, one of the major failures I had was NOT THE MOTOR, but the wire insulators! This was a non Minn Kota (or a really old Minn Kota). Was running it at 48V burst and about 24V average. 3 people in a Ocean Kayak - anyway - wind picked up and we had to get into harbor. I drove it harder than intended for over a minute... SMOKE shot out of the pipe... lol...

Long story short the cheap-ass wires had a low temperature insulation and it literally just melted resulting in short - so - think about that...


Failure: Brushes

Of course, if you are running a brushed motor that is intended to be reliable at 12V and you hammer it with 24V all day, every day... you are going to see increased wear. The same is not true at all with a Brushless motor, so think about that. Go Brushless any time you can, this moves your limiting factors to the Controller.

* Controller mosfet voltage rating
* Controller Electrolytic voltage rating
* Controller Regulator tuning (To create 12V and 5V rails)

Anyhow, you can run any brushless motor off of any brushless controller... and there are MANY... RC, Ebike, you name it... so... back to Brushed.

...
Running something like a Minn Kota Endura Pro 32lb (cheapest and most common) on 24V will work for a long time. Eventually you will wear thru the brushes and they will need to be replaced. You can just open up the motor and see... (when it fails) ... that one or both of your brushes have worn down to the nub*

Now...
Trolling motors are supposed to be reliable... so those brushes are supposed to basically be "Lifetime" - so ... you may want to invest $5 in some replacement brushes. Search: "minn kota replacement brushes"

Anyhow -
I have had the brushes go on a Minn Kota, but... to be fair... in that case:
* Motor came used with A LOT of hours from an unknown source
* Hooked 24V directly to the speed controller (Two 12V in series)
* Ran it in Salt Water for years (it is a fresh water motor)

... All of these things start to add up. Saltwater intrusion, increased RPM, Increased heating of brushes.... so... What you have to accept is that there is no Binary Answer to the question: "Can I over-volt my Trolling Motor?"

Binary Answer? NO
Analog Answer? YES, OF COURSE... Caveat.

So...
My recommendation (I am methods) goes as follows

* 12V lead - will run forever
* 12V Lithium - will run forever
* 18V Lithium - will run for damn near ever
* 24V Lithium - will burn thru brushess, so get ahead of it
* More - requires a Speed Controller and great discipline

Today I am picking up another Minn Kota Endura Pro 32lb. It has 6 trips on it and looks to be about new. I will go about things in the following way:

* Tear it down and inspect the brushes
* Run it off of 18V Ryobi batteries for 42 hours
* Tear it down and inspect

Right?
The way you build reliability is by collecting Scientific Data.

* Baseline
* Single Change
* Re-assess

In this case, the changes we will be making are

* Fresh to Saltwater
* 12V lead to 18V Lithium
* Aluminum Boat load, to ... much less load

I am building an underwater scooter in two stages
1) Attached to a boogieboard
2) Attached to a pair of BMX handlebars

Step 1 is to assess how much twisting there is and if the Scuba idea is a bust. I can tell you that I DO NOT want to go twirling in circles underwater right next to a moving prop...

PAUSE

-methods
 
Just in case there is any question, -> "Pics or it didn't happen"
 

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Since I may not ever be back, here is a Core Information dump

* You attach a Trolling Motor to a Kayak using "Blind Rubber Nuts" and a simple plywood transom. You can pick up the fasteners at a marine store like West Marine. Inside the nut will be brass or Stainless - anyway - they work just like a wall anchor

- Drill a hole
- Insert the Blind Rubber Nut
- Fasten down to expand the rubber

That will get your transom mounted to your plastic Kayak in about 5 minutes with damage that is quite repairable.

* You can repair a standard Kayak with a small torch by plastic-welding. You can also patch in many other ways, with any material that will bond to your particular "Plastic" (whatever that may be)

eh...
Golf Cart Controllers

* Most people want a performance increase. This means going from 36V to 48V, or going from 350A to 500A. For this reason, the PWM Brushed controllers in the 36V 300A range are commonly found as pull-down. They are undesirable and can be had for almost free. They are potted (very water resistant) and highly reliable. I suggest using them any time you can.

* You will throw away the Trolling Motor electronics - dont need them.

* There may be Diodes or other Inline Resistance-type controller parts down in the motor

Ignore that crap. We never use Resistor packs for speed control. That is savage and unacceptable. So - when you cut the shaft on your trolling motor you may find 5 wires. Two of those are guaranteed to go straight to the motor for FULL SPEED... so... Ohm it out and see.

eh...

For Ryobi and other Tool Packs I use a plastic adapter. You can find them on Amazon, I select the model that has 12AWG over 14AWG as your copper wires are often your only Heat Sink when overvolting things.

eh...

A Brushless Trolling motor is like the holly grail. It has near infinite heat sinking so ... you could probably do almost anything to it. I have yet to get my hands on one, but once I do... we will really get into re-propping. You can play with RPM and Torque. For a light weight boat, adding more torque wont do much for you... but increasing RPM sure will!

At some point you will need to re-prop to a prop that is better suited to the increased RPM.

eh...

A Brushless Hub Motor (any size) would make for an epic trolling motor. You CAN run them underwater* You would just need to drill the covers and wash them out really well after every trip. The are made of mild steel and the magnets rust like hell... but you COULD experiment with a hub motor under salt water.

I may - better idea is to keep it mounted above the water line and use a simple transmission. Any old blown 2hp motor would be the ultimate candidate for conversion over to Electric. The Compression goes bad on those old motors and...

-Schindler
 

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Final Thought
There is no such thing as a "Dead Thread" where the Electric Revolution is concerned. Even something from 2010 is still supremely relevant as the Public in General is still... completely unaware of these basics.

If you have information, share it. Especially information around Brushless thrust devices that are 1/3hp to 2hp.

-methods
 
Disclaimers:

* If you follow any of my advice then it is assumed you are willing to blow a few motors or controllers up

The primary failure mode of over-volting brushed equipment will be in heat generation. The increase in voltage over the basically fixed load will increase current draw. Increased current draw will generate heat to the square of current.

Heat = Power
Power = Current Squared x Resistance

Heat on the motor windings is not the issue here (as it is with Ebikes). The motors are water cooled. The real damage will build up at the Brushes. They are now commutating much more current... and... they are seeing a bigger spark at every jump

So
* Run the best brushes you can find
* Try to find a way to heat sink the brushes

If you use the factory PWM controller, it may need additional heat sinking. Just crack the case and fix a big aluminum heat sink on there and for the most part it will probably be fine. Very few 12V rated parts will blow at 18V or 20V. A lead acid battery can be 14.4V hot off the charger, so no supplier of "reliable equipment" is going to populate with 16V components. Not enough margin*

You can almost always sneak "18V" (so 21V hot off the charger - 5S) on old 12V equipment*

So...
* Get the heat out of the brushes
* Inspect your brushes regularly

Mind your wires!
You want to use wires rated for 90C or 105C wherever you can. Strip out and cut away the junk wires that these things come with. They were Value Engineered to run off of a saggy 12V battery. Go heavy! 10AWG minimum. Wiring acts as a heat sink for Burst.

* Be Smart!
* Run as close to nominal where you can
* Keep burst power down to a minimum

I commonly FLY off of the dock to show off for the other boaters, but as soon as I am in the channel I back my throttle off to something manageable. If you keep your heat generation (Average) close to factory, then you can enjoy BURST performance with Reliability. Exactly the same as ebikes.

Ebikes
I commonly run 88V+
I commonly run 100A+ current limit

This is on a standard 36V 1hp ebike hub. OF COURSE... if you point it straight up hill and bog it... it will destroy your controller or motor pretty quick. Bursting Power is what this is all about once you get things to not instantly explode due to voltage in excess of rated parts*

So...
* Mind you Temperatures!

Take it apart!
These machines are serviceable. You want to get very comfortable with disassembling your brushed trolling motor. If you do not, then... you will end up with a surprise failure. When you are assessing reliability on an over-volted device you want to be able to get in there and inspect.

* remove the prop
* remove the fasteners
* inspect the seals and ingress

Use a Marine Rated grease on all o-rings. This GREATLY increases the sealing performance, especially on older equipment. As the motor heats and cools it will expand and contract. This creates odd vacuums and pressures, allowing more liquid in than normal. Until you have a baseline you are going to want to tear down your motor, clear out any ingress, re-pack with grease.

Use a Dielectric grease anywhere near exposed electrical terminals. Use a Marine Grease anywhere near the water interface. Different greases wash away in different ways.

eh...

Always have a Plan B
If you are over-volting a trolling motor then you better have a plan in place

* Oars at a minimum
* Backup motor

Unless you like rowing, I suggest bringing along some secondary propulsion source... at least until you have determined a reliability regime that can get you out and back. I go out into Open Water (ocean) and the weather sometimes changes. So...

* Wear a Wetsuit
* Bring Fins

I wear a 4:3 wetsuit that doubles as a flotation device. I bring swim fins... as... I am the secondary propulsion device.

Prepare to get wet!
If you are attaching 48V to a 32lb thrust trolling motor on a Sea Kayak... you better be experienced and ready to get wet

* dont bring anything that does not float
* Keep the batteries in something that can fall in the water

The little boats get squirrely! If you goose it 48V with the prop to the side it will move you quick... so... I go out with the ASSUMPTION that we are doing exercises and that WE ARE going to go into the drink.

Disclaimer Done

For waterproofing you can use the knock-off "Zero Case". These are the locking cases with an O-ring seal and check valve. You then drill those for two brass studs - they are easy to find. Brass studs have an o-ring seal or mounting surface. In this way, your lithium stays dry and you bring out only two wires. BEWARE... of the following

* Batteries generate heat
* Contactor Coils generate a lot of heat

So - think about getting heat out of the battery box if you are going sealed. A lot of cooling happens Radiant - A LOT. I typically use DT bulkhead connectors for IP67 needs. They leak a little, but - we are not looking to go under water. We are looking to survive a rollover and get back to shore.

eh...

Split your Battery in Two
Where boating is concerned, it is far better to have TWO small batteries than 1 large. You will learn this the hard way when you have to paddle 3 miles. Just like Ebiking... it is easy to lose track of time. Remember that the following affect your range:

* Currents
* Wind

So... when you head out, head out up current and into the wind. Use only half of your pack and when that runs dry, turn your ass around and head back in. There is no shame in burning only 60% of your capacity. There is great shame if the Coast Guard has to come out and get you.

:)

-methods
 
I have done this many times with voltages up to 50V on Minn Kota 12V as well as other trolling brands..........

I know that you are new to the forums, but there was a warning written in red telling you this thread has not seen activity in at least three years that you disregarded.

In fact, this thread is 11 years 8 months old now that you just resurrected rather than start your own new thread/topic

The persons who participated in the thread are long gone now and you should expect no answer from them...

Re-activating OLD threads accomplishes nothing.

The ADMIN of the forum took the time and effort to put that warning in red
to all in the forums so that everyone would see and know that this is an out of date thread.

Otherwise, We do welcome you to the forums, and in future, PLEASE read those thingy's marked in red as well as the date of the posts which are marked in the upper left hand corner of the posting...DAMIEN
 
I can't resist to comment, Besides I get to show some kayak 🐟 pics :ROFLMAO:

With the advancements in 12v Lithium Marine batteries, @methods is silly Pushing the Minn Kota Trolling Motor past 12v
Of course anyone can put higher voltage to a 12v Minn Kota Trolling Motor but it's not designed to handle it
I WONDER WHY HE KEEPS FRYING WIRES AND MOTORS :ROFLMAO: He said "if you follow his advice your gonna blow motors" :ROFLMAO:

I have a 12v salt water 45lb thrust Minikota. $200 I use a Group 27 West Marine 12v Gel Battery 88AH $300
This battery is great it's still performing like new after 10 years. (y)
Yes I have all this on my Kayak and yes I take it out in the Ocean and go fishing all day
It always has plenty of power as I usually cruise on speed 5.

I think the solution to having enough power that lasts a long time is to Invest in a good 12v Gel or Lithium Marine battery for your 12v Minn Kota Trolling Motor. I have never been stranded in the ocean or had to Paddle to shore because I ran out of battery power


I'll show my Kayak set up and I can't resist but to show some 🐟 pics too. :ROFLMAO:

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