Brushed vs Brushless Trolling Motor: What Changes on the Water
Brushed vs brushless trolling motor: how each design works and how they differ in efficiency, sonar interference, wear parts, battery fit, and cost.
Updated October 27, 2026
The brushed vs brushless trolling motor choice comes down to how you fish. If you run a kayak or small jon boat on one 12-volt deep-cycle battery for short trips, a brushed motor does the job, costs less, and is the design Newport uses in its Kayak Series and NV Series. If you spend long days on the trolling motor or watch scanning or forward-facing sonar off the bow, brushless is the design to look for. The rest of this comparison explains why, drawing on what the makers publish on the pages and manuals we opened, plus general background on how the two designs work.
The core difference is how the motor switches current through its windings: mechanically, through carbon brushes rubbing on a spinning commutator, or electronically, through a controller with no rubbing contacts. That one change affects efficiency, sonar noise, wear parts, and cost.
This guide is general product information, not repair or electrical safety advice. Follow the installation, wiring, and charging instructions in your product’s manual, stop using any battery, charger, or electronics that overheat, swell, or smell of burning, and contact the manufacturer.
Brushed vs Brushless Trolling Motor at a Glance
Sources: Newport’s Kayak Series and NV Series product pages, its NK180 HD page and NK180 vs. Trolling Motor article, Garmin’s trolling motor buying article, and the Force owner’s manual. The table compares the two designs, not specific models.
| Feature | Brushed trolling motor | Brushless trolling motor |
|---|---|---|
| How current is switched | Carbon brushes in contact with a rotating commutator | Electronic controller, no brush contact |
| Efficiency | “Not as efficient as brushless,” per Newport | More efficient than brushed, per Newport; Garmin calls its own brushless Force Kraken “extremely efficient” (no comparison given, no percentage published) |
| Sonar interference | No figure published by the makers we checked | Garmin says its brushless Force and Kraken motors keep interference very low |
| Wear parts in the motor | Brushes; Newport sells a brush assembly with thrust options from 36 to 86 lb | No brushes; Newport lists the NK180 HD as maintenance-free |
| Lithium batteries | Newport cautions that 14 to 16 V lithium output can wear brushed motors | Newport’s NK180 HD spec table lists a 24 V LiFePO4 battery (a Newport article also names lead-acid) |
| Where you find it | Newport Kayak Series and NV Series (per Newport) | Garmin Force, Force Pro, Force Current, and Force Kraken; Newport NK180 HD (sold as an electric outboard) |
| Cost | Lower price point, per Newport’s comparison | Higher price point than Newport’s trolling motors, per Newport’s comparison (NK180) |
How Each Motor Design Works
Inside a brushed DC motor, the windings sit on the spinning armature, and fixed magnets surround it. Current reaches those windings through carbon brushes pressed against a segmented ring called the commutator; as the armature turns, the brushes slide from segment to segment and flip the current to keep it turning. The design is simple and needs little electronics.
That sliding contact is also the weak point. Brushes wear down, create friction and heat (wasted battery energy), and can arc slightly as they cross the commutator gaps, which can add electrical noise.
A brushless motor flips the layout: magnets on the spinning part, fixed windings, and an electronic controller that switches current through them in sequence. Nothing rubs to deliver power. The trade-off is that the motor cannot run without its controller, which adds cost. Newport’s comparison article describes its brushed trolling motors and its brushless NK180 as using “different technologies to achieve different goals at different price points.”
Efficiency and Run Time
Efficiency is the main reason anglers ask about brushless. Newport states plainly that “brushed technology is not as efficient as brushless,” and its kayak motor setup article says charts on that page show “the direct-drive brushless technology is much more efficient than the brushed technology.” Garmin’s Force Kraken press release describes the motor as “extremely efficient so anglers can count on it to fish all day.” Neither maker gives a general percentage for brushed versus brushless, so we do not quote one.
On the water, efficiency means more fishing time from the same battery, though how much you gain depends on throttle habits as much as motor type. Speed is a separate question: Newport sells its faster brushless NK180 as an electric outboard, not a trolling motor, and our guide on how fast a trolling motor goes covers top speed.
Noise and Sonar Interference
Sonar interference is where brushless matters most to fish finder users. In its launch article for the Force, Garmin says that thanks to its brushless motor, the Force runs with “nearly undetectable interference” so it does not fill the sonar screen with static. The Kraken press release makes a similar claim: “no matter the sonar setup,” the brushless motor “allows for clear returns with extremely low levels of unwanted noise from electrical and mechanical interference.” These are the maker’s descriptions of its own motors, not a measured comparison.
That does not mean every brushed motor ruins a sonar picture. Newport describes its brushed Kayak Series as offering “whisper-quiet operation” and lists “Smooth, Quiet Operation” for the brushed NV Series. Cable routing can also affect interference. Garmin’s transom and trolling motor transducer instructions say that for “the lowest noise and interference,” you should route the transducer cable away from trolling motor batteries and wires. Fix routing first; if clutter still appears whenever the motor runs, the motor type becomes a fair suspect.
Wear, Maintenance, and Lifespan
Brushes are a wear part. Newport sells a brush assembly (part #17-22) with thrust options from 36 to 86 lb; the page does not say which models it fits. Replacing them is internal motor work, so follow the manual or use the maker’s service network.
Brushless removes that part, and Newport lists its NK180 HD as maintenance-free. That is not the same as no care: the routine list in Garmin’s Force owner’s manual still covers power terminals, hinges, the stow latch, mount parts, and anodes, plus a fresh-water rinse after salt use. Neither maker publishes an expected lifespan for either design, so we do not offer one.
Batteries: Lithium and Voltage Notes
Motor type changes the battery conversation. In the same kayak motor setup article, Newport says many lithium batteries put out 14 to 16 V when fully charged, “which can wear down or damage DC Brushed motors,” and suggests a lithium battery rated at 13.8 V or less. Its brushless NK180 HD lists a 24 V LiFePO4 battery in its spec table, and Newport’s NK180 comparison article says the NK180 runs on 24 V lead-acid or lithium.
Brushless does not automatically mean lithium-ready or high voltage only. Garmin says its brushless Force Current delivers 30 lb of thrust on 12 V or 50 lb on 24 V. The original Force manual notes that its battery level indicator is optimized for lead-acid batteries and may read inaccurately with lithium-ion, while the Force Current owner’s manual says its indicator defaults to lithium iron phosphate. For either design, use the battery type and voltage your motor’s manual lists.
Who Does Not Need a Brushless Trolling Motor
Plenty of anglers can skip brushless without giving up much:
- Short sessions on a small boat. Newport designs its brushed Kayak Series for kayaks, canoes, and pedal boats running one 12-volt deep-cycle battery. Sizing thrust to your boat matters more here than motor type.
- Occasional use. If the motor only creeps you along a shoreline now and then, the efficiency gain has little time to pay off.
- A clean sonar screen already. If your fish finder shows no motor clutter with the cables routed as the maker directs, interference is not a reason to upgrade.
- A tight budget. Newport’s own comparison puts its brushless NK180 at a higher price point than its trolling motors, so a tight budget favors brushed.
A brushed motor may be a poor fit if you run the motor for most of the day on one battery bank (Newport rates brushed as less efficient), rely on bow-mounted scanning or forward-facing sonar, or already run lithium batteries that your brushed motor’s maker does not approve.
Which Should You Buy?
- Kayak or small jon boat, half-day trips: a brushed transom motor on a 12-volt battery is the practical choice.
- Bass boat with bow-mounted sonar, or long days holding a spot: brushless, for the low interference Garmin describes and Newport’s efficiency comparison.
- Already committed to lithium: choose a motor whose manual lists lithium support.
If you are still working out the basics of what a trolling motor does, start with our separate guides. We also cover run time on a 12-volt battery and everyday trolling motor operation, and the trolling motors section collects everything we publish on the subject.
Why You Should Trust Us
We do not conduct our own product trials, and this comparison does not rank products. It draws on Newport’s and Garmin’s product pages, owner’s manuals, installation instructions, and published articles, each linked where it is used. Where a maker gives no figure, such as a general efficiency percentage or a lifespan in hours, we say so instead of filling the gap. We earn a commission from qualifying purchases on some pages, and commissions never affect our recommendations or scores. You can read the full method on our How We Review page.
Frequently Asked Questions
Is a brushless trolling motor worth it?
It is if you run the motor for long stretches or depend on sonar near it. For short trips on a small boat, a brushed motor usually covers the need at a lower price point.
How can I tell if my trolling motor is brushed or brushless?
Check the specification sheet or owner’s manual. Newport, for example, lists “Motor: Brushed” or “Brushless” on its product pages, and Garmin’s articles on the Force line name the brushless motor. If the maker sells a brush assembly as a replacement part for your exact model, it is a brushed motor.
Do brushless trolling motors cause less sonar interference?
Garmin says its brushless Force and Force Kraken motors produce very little electrical interference on sonar. Cable routing still matters with any motor.
Can I use a lithium battery with a brushed trolling motor?
Only if your motor’s maker allows it. Newport cautions that many lithium batteries at 14 to 16 V when fully charged can wear down or damage brushed motors. Read your manual first.
Do brushless trolling motors last longer?
They have no brushes to wear out, but neither Newport nor Garmin publishes a lifespan comparison. Saltwater care, storage, and battery maintenance still shape how long any motor lasts.
About the author
Brent Curtis enjoys chasing largemouth bass on Alabama lakes, especially around submerged structures and weed beds. He uses side-imaging fish finders and GPS trolling motors to locate fish, hold his boat in position, and explore productive fishing spots.