Trolling motor for sale near me: What size battery for trolling motor ?

Finding the right trolling motor for your boat can be challenging enough but how do you fix it to your boat and how do you keep it in tip-top condition? In this post, we will take you through everything you need to know to pick the right battery, trolling motor and potion to place it on your boat.
Once you’ve picked the right trolling motor for you, check out our ‘trolling motor for sale near me’ tool below:

What size battery for trolling motor

trolling motor batteryChoosing the right battery for your trolling motor is key. For this reason, you should always choose deep cycle marine batteries rather than shoving an auto battery in your boat. These batteries are designed to cope with deep discharges if necessary in a way that would just kill a car battery so even if you pay more upfront, you’ll get a longer lifespan with a marine battery. However, ideally, you should still not discharge your marine battery more than 80% and definitely avoid below 50% for optimal use.
The ideal battery for trolling motors will vary and obviously needs to match your motor, but typically a 12-volt deep cycling marine battery with a minimum amp hour rating of 110 amp hours (Group 27) is a fine choice for boats under 16 feet long. If you have slightly more cash to spare, a group 31 battery is optimal. Otherwise, for boats longer than 16 feet, it may be worth opting for a 24-volt trolling motor and an accompanying 24-volt battery. Some boats even operate on a 36-volt system. Minn Kota offer some of the best quality batteries for trolling for a decent price.
You also need to consider how long you’re going to be running your battery. This involves thinking about speed as, if you are traveling faster you are going to drain your battery faster. For example, if you run your 110 amp-hour battery for 4 hours at low speed, drawing on just 5 amps, you’ll get 22 hours out of it (110/5). Running at high speed and drawing on 40 amps, you’d drain the battery completely (not recommended) in just under 3 hours!
Top tip: Consider installing a 3 bank charger. This will allow you to keep your cranking battery charged when spending long days out on the water running multiple devices.

How to wire a 24 volt trolling motor

Since larger trolling motors often use 24 volt systems, it is handy to know how 24 volt trolling motors are wired. The 24 volt wiring diagram above illustrates how to do it using 2 12-volt batteries. It’s important to note that the circuit breaker needs to be wired in place within 4 inches of the battery you connect it to. You should also never pump more voltage through your motor than it is rated to handle – pumping 36 volts into your 24 volt troller is just going to ruin it.
The batteries are then connected in series which connects:

Top tip: Use protective shields to cover your positive terminals for safety purposes. You can also use electrical tape to cover the terminals if needed. The important thing is to ensure they cannot come into contact with any metal objects or anything that could create a circuit.

How to charge a trolling motor battery from the outboard motor

All you need to do to charge a trolling motor battery from the outboard motor is to connect a combiner in between the trolling battery and the starting battery. With a combiner installed, whenever your engine is running, charging output will be shared with your cranking battery and your trolling battery. The combiner will also ensure you don’t accidentally discharge your starting battery when the engine is off.
Here are 5 easy steps to get you started:

  1. Mount your combiner:

This should be near to the starting battery (within 2-feet ideally).

  1. Connect 1 (of 2) combiner lead(s) to the positive terminal of your starting battery:

The combiner will have 2 leads of the same color, make sure only one is attached to anything to ensure you don’t short circuit your combiner.

  1. Connect 1 (of 2) combiner lead(s) to the positive terminal of your trolling battery:

You will often need to use an extension cable to do this – a 10 gauge duplex cable is a good choice.

  1. Connect the negatives between both batteries.
  2. Connect the third unique colored lead from the combiner to the negative of the starting battery.

There may be 4 wires, typically the green one is not required so it can be cut off and covered with insulation tape so that it does not come into contact with anything. With these 5 steps, you’re done and whenever you turn on your engine, the combiner will do the rest.

What size trolling motor do I need for my boat?

When it comes to how to choose the right size trolling motor for boats, you are going to have to consider three key areas: thrust, boat weight, and boating location plans. Thrust is measured in pounds and you need more thrust for larger and heavier boats. However, to figure out what thrust you need, you really need to know the weight of your boat. Typically for every 110 pounds, your boat weighs you’ll need at least 2 pounds of thrust. The following equation works nicely:
(Boat weight/100) X 2 = necessary thrust
Obviously, you will need to take into account the weight of things on the boat as well as the base weight of the boat, including everything from fuel to passengers. Finally, you also need to think about where you plan to fish and under what conditions. If you’re only going to be taking your boat out on calm and tranquil lakes, you should be fine meeting minimum calculated requirements. If you’re often in fast waters or heading out to sea, you want to factor that into your thrust calculations.
For a good idea of the sort of thrust you will need for different boat lengths and weights, check out the table below:

Boat Weight (lbs) Boat Length (feet) Minimum Thrust Optimum Thrust Trolling Motor Voltage Required
1,500 <14 30 40 12
2,000 15-16 40 50 12
2,500 17 50 60 12
3,000 18 60 70 12
3,500 19 70 80 24
4,000 20 80 90 24
4,500 21 90 100 36
5,000 >21 100 >100 36

Top tip: remember you need to factor in the additional weight you add to your boat when calculating necessary thrust power. Try and think of the heaviest you might ever need your boat to be and pick thrust power to meet those maximum needs so as not be disappointed with your decision (and give you some cover for any bad math).

How to take apart a Minn Kota trolling motor

If you are running a trolling motor of any kind, you are going to know how to perform maintenance on it periodically. Minn Kota motors are relatively easy to disassemble with just a few hand tools. Typically, the areas that will tend to need troubleshooting and repair most often are the wiring and the motor housing. Here are 7 easy steps to safely take apart your trolling motor:

#1 Reveal the wiring

These are revealed by approaching through the collars and the shaft neck.

#2 Detach the wiring

Remove the wiring (red and black wires) that are attached between the trolling motor and your marine battery.

#3 Remove the motor housing

Refer to your user manual to find the location of the small set screws keeping the motor housing secure. On Minn Kota motors these are usually found somewhere along the top. Unscrew these, and put them somewhere safe. You can now also pull off the motor housing to reveal the electric engine inside.

#4 Remove the electric motor

Locate the set screws, which will be found somewhere on the engine bracket, and place them somewhere safe – remember, you need to be sure where each of the screws you’ve removed goes when you put it back together. Be careful to remove the motor gently from the engine bracket once you have removed the screws.

#5 Remove the cover of the control box

Use a flathead screwdriver to remove the cover of the control box. This is found where the shaft and the control stick meet, near to the collar.

#6 Widen the collar

With the cover removed, you are free to widen the collar. This can be done with a screwdriver. You will now be able to pull through wiring out of the shaft.

#7 Remove the propeller

Once the wiring has been drawn up and out of the shaft, you can unscrew your propeller. You will need a prop key tool to do this – remember with a prop key you turn right to loosen rather than left. Finally, you are free to remove the propeller and you have successfully disassembled your trolling motor.

How to mount a trolling motor on an aluminum boat

Your troller can be positioned on the bow, the transom (sometimes known as the stern or rear of the boat), or on the engine. Here, we will outline the classic way to position your trolling motor – on the transom of an aluminum boat.

#1 Open brackets

If you are mounting a trolling motor on your transom you will need two clamps. Usually, these will be built into the motor itself. To open the brackets, you need to turn the clamp handles to the left (remember the saying ‘righty tighty – lefty Lucy’ if you’re ever unsure about which way to turn something to tighten it).

#2 Attach motor to transom

Make sure you attach the motor centrally against the stern. The top bracket connecting your trolling motor should also be flush to the very top of the stern. You also want to ensure that the propeller will be deep enough so that it never breaks the water’s surface when fully engaged. If the propeller is positioned in such a way that it breaks the water surface when running, fish will hate it and flee.

#3 Fasten the clamps

With the trolling motor fixed flush in the centre atop your transom you are now good to tighten the clamps by turning them to the right. You need to tighten these as far as they can possibly go as the vibrations of the troller can loosen these if you are not careful. It’s no joke when your clamps haven’t been done tightly enough and you see your motor slide off the back of your boat into the water.

How to put a trolling motor on a kayak

Whilst it is possible to design your own mount to attach a trolling motor onto your kayak, these days it is much easier to buy a kit off the shelf. This will cost more than a homemade option but, typically, look more stylish and are less liable to break, either themselves or the kayak you attach them to. As they have been specially designed, they also tend to be easier to maneuver. Indeed, you’ll be impressed how easy it is to steer your kayak when using a trolling motor mounting kit.


So there you have it, picking the right battery, trolling motor, and getting it fixed to your boat is easy when you know-how. Once you’ve got your system in place, it’s also vital to remember to maintain your battery and motor properly. This means regularly charging your battery and not letting in drain too deeply even if it is a good quality deep-cycling battery and performing regular maintenance on your motor. All you need to do now is go get that motor running!

Exit mobile version