Trolling motors
Twelve, twenty four or thirty six volts: which trolling motor system fits your boat?
Quick answer
Twelve volts tops out at 55 lb of thrust, 24 volts covers 70 and 80 lb, and 36 volts starts at 101 lb, and each step adds one permanent battery. Counterintuitively, the 112 lb 36 volt motor draws less current, 52 amps, than the 80 lb 24 volt motor at 56 amps, since higher voltage needs less current for the same power.
Minn Kota Terrova 55 with GPS and Spot-Lock, 54 inch shaft
$1,649.99 Published specsThe largest thrust class 12 volts reaches, on one battery
Best for: The buy-once bow motor for a single battery freshwater boat
Check price on Amazon
Minn Kota Terrova 112 with Spot-Lock and MEGA Down Imaging, 60 inch shaft
$2,399.99 Published specsThe largest stocked bow mount thrust class, on a permanent three battery bank
Check price on AmazonSystem voltage is not a preference on a trolling motor, it is a ceiling. Twelve volts runs one battery and tops out at 55 lb of thrust. Twenty four volts runs two batteries in series and covers the 70 and 80 lb class. Thirty six volts runs three batteries and is the only way to reach 101 lb of thrust or more. A heavier boat, more wind, or more current all push the required thrust up, and past a certain point that pushes the voltage class up with it whether you planned on carrying a second or third battery or not.
The battery count is the real cost of moving up a voltage class, more than the motor's own price tag. Each step adds one permanent battery to the boat, roughly 60 lb in lead acid per battery, wired in series with the others and living in the hull for the life of the motor. That weight and that wiring do not go away between trips the way a portable charger does.
Thrust needed also depends on how loaded and how exposed the boat actually is, which the 24 volt Terrova 80 covers for a mid size boat and the 36 volt Terrova 112 covers once the boat, the wind or the current push past what 24 volts can move.
On this page
How much thrust does your boat actually need
Two pounds of thrust per hundred pounds of fully loaded boat, meaning hull, motor, batteries, fuel, gear and everyone aboard, is the number every retailer and forum repeats, and it is convention rather than a published engineering standard. It also assumes flat water with no wind, which is rarely the day anybody actually needs the motor.
The conventional figure is 2 lb of thrust per 100 lb of fully loaded boat in calm water, rising to 5 lb per 100 lb in wind, current or big water, and no standards body publishes either number.
Rule of thumb Boating and fishing convention rather than a published standard. Taught everywhere, useful, and not a specification. Nothing enforces it and no body publishes it.
| Condition | Thrust per 100 lb loaded | Note |
|---|---|---|
| Sheltered, little wind | 2 lb | A floor, not a target, for flat calm water only |
| Normal lake conditions | 3 lb | The typical planning figure for an average day |
| Wind, current or big water | 5 lb | The figure to plan around if the water is rarely flat |
Run your own loaded weight through the trolling motor thrust calculator rather than eyeballing it; every pound in the boat on the day you fish counts, not just the empty hull weight on the spec sheet.
Where each voltage class stops, in real stocked motors
Twelve volts is stocked up to 55 lb on one battery, 24 volts covers 70 and 80 lb on two batteries, and 36 volts starts at 101 lb on three batteries.
Published figure A published engineering, regulatory or manufacturer figure. It does not change because somebody disagrees with it.
| Thrust | Volts | Batteries |
|---|---|---|
| 30 to 55 lb | 12 | 1 |
| 70 to 80 lb | 24 | 2 |
| 101 to 112 lb | 36 | 3 |
These are the thrust classes actually stocked across the mainstream motor lineup, not a theoretical voltage rule. A motor rated between two rows does not exist; you buy the next size up.
The counterintuitive part: more thrust does not always mean more current
The 112 lb 36 volt Terrova draws a published maximum of 52 amps, less than the 80 lb 24 volt Terrova's published 56 amps, despite moving considerably more boat. That is not a typo and it is not an efficiency difference between the two motors. Electrical power is voltage multiplied by current, so delivering more power, meaning more thrust, at a higher voltage takes less current to do it. The 55 lb 12 volt motor sits in between at 50 amps published maximum draw, which means the amperage does not simply track thrust in a straight line across the three voltage classes at all.
Manufacturer published maximum draw runs 50 amps at 55 lb on 12 volts, 56 amps at 80 lb on 24 volts, and only 52 amps at 112 lb on 36 volts, the highest thrust class of the three drawing less current than the class below it.
Published figure A published engineering, regulatory or manufacturer figure. It does not change because somebody disagrees with it.
| Thrust | Volts | Published max draw |
|---|---|---|
| 55 lb | 12 | 50 A |
| 80 lb | 24 | 56 A |
| 112 lb | 36 | 52 A |
Always check the published maximum draw for your own specific motor. This is why the same size wire and breaker cannot be assumed to carry over between voltage classes without checking the actual number.
Why the battery count matters more than the motor price
Moving from 12 to 24 volts means wiring two 12 volt batteries in series rather than buying one bigger battery, and moving to 36 volts means three. Each battery in a lead acid bank weighs roughly 60 lb, so a 36 volt system commits the boat to something in the neighborhood of 180 lb of permanent battery weight before the motor, the charger or the wiring are even counted. A single 36 volt lithium pack sidesteps the series wiring and cuts that weight considerably, at a price that is its own part of the decision. Whichever chemistry the bank ends up as, charge it on a charger with the matching lithium or lead acid profile selected, since a lithium pack held on the wrong profile either never reaches the voltage it needs to fill or sits at a float voltage it should not hold.
Which voltage class should you actually buy
Buy 12 volts if your fully loaded boat and typical conditions land at 55 lb of thrust or under, since one battery is simpler to wire, cheaper to replace, and lighter in the hull. Move to 24 volts once the math crosses 55 lb or the water you fish is regularly windy enough that the calm water number understates what you need. Only go to 36 volts if the boat is genuinely heavy, the water is genuinely rough, or you are chasing the top of the thrust range on purpose, because three permanent batteries is a real and lasting commitment rather than a small upgrade.
Frequently asked questions
Can I run a 24 volt trolling motor on a single 24 volt battery instead of two 12 volt batteries?
Only if you buy a battery that is itself built and rated as a 24 volt pack, which exists in lithium but is unusual in lead acid. The far more common setup wires two 12 volt batteries in series to produce 24 volts, and swapping that for a single 24 volt lithium pack is a real option but a different purchase, wiring and charger decision than simply adding a second 12 volt battery.
Why does the 36 volt motor draw less current than the 24 volt one?
Because power equals voltage multiplied by current, so delivering more power, in this case more thrust, at a higher voltage takes proportionally less current to do it. The published maximum draw figures bear this out directly: the 112 lb 36 volt Terrova draws 52 amps against 56 amps for the 80 lb 24 volt Terrova, despite the 36 volt motor moving considerably more boat.
Does upgrading from 12 to 24 volts always mean buying a new motor?
Yes. A 12 volt motor is built for that voltage internally and cannot simply be rewired to run on 24 or 36 volts by adding batteries. Moving to a higher voltage class means buying a motor built for that system, along with the additional battery, the wiring to connect the bank in series, and in most cases a multi-bank onboard charger rated for the new number of batteries.
Is the 2 pounds of thrust per 100 pounds rule accurate for every boat?
It is a widely repeated planning convention rather than an engineering standard, and it assumes flat calm water. A boat that regularly fishes wind, current or big water is better served by the 5 pounds per 100 pounds figure for the same reason a sailor plans around the worst likely day rather than the best one. Treat either number as a starting point and confirm against your own conditions.
How much does a 36 volt battery bank actually weigh?
In lead acid, roughly 180 lb across three batteries at about 60 lb each, though the exact figure depends on the specific battery and its own published weight. A single 36 volt lithium pack replaces that series wired trio at a fraction of the weight, which is the main reason lithium shows up so often on boats running the largest thrust classes.
What size breaker or fuse does a 36 volt trolling motor need?
Size it to the motor's own published maximum draw, not to a number pulled from the thrust rating alone, since the current draw does not scale in a straight line with thrust across the voltage classes. Check the manufacturer's own specified circuit breaker for your specific motor first, since where one is published it governs over any general sizing convention.
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Researched, not professional advice. This page is compiled from published engineering and regulatory figures, manufacturer specifications and owner-review consensus, not hands-on testing. Figures described as a rule of thumb are boating convention rather than published standards, and they are labelled that way wherever they appear. Marine electrical work is not house wiring. Use tinned, finely stranded marine cable, size it for voltage drop and for the ABYC E-11 ampacity table rather than one or the other, and put overcurrent protection within seven inches of the battery positive terminal, because everything between the post and the fuse is unprotected. A lithium battery needs a charger with a lithium profile. Never load a boat past its capacity plate, and remember that canoes and kayaks carry no federal capacity plate at all, so their stated capacity is the manufacturer own figure. Wear the life jacket, and treat early season water as the hazard it is: cold water immersion takes your breath and then your hands long before it takes your core.