Choosing an electric outboard

Maybe electric outboards aren’t just for occasional use or short trips

There a lot of choices for electric outboards these days. Here are three that have a good mix of convenience, power, durability, and good reputation. Each of these manufacturers has a range of electric outboards. I’ve chosen the 1 kWh, which are equivalent to 3 HP, that are most suitable for small sailboats and tenders.

Contents

• Range anxiety
• What to expect from a small electric outboard
• Mercury Avator 7.5e
• ePropulsion Spirit 1.0 Plus 1 kW
• Torqeedo Travel S

Range anxiety

Let’s get this out of the way. The anxiety over this is understandable. But electric outboards have evolved a lot in the past 10-15 years. They’ve obviously reached mainstream acceptance with big players like Mercury and Yamaha making serious commitments to selling them.

Reminding yourself of some physics is a good way to let go of range anxiety. Just like combustion engines, an electric’s range decreases exponentially the faster you go. Generally speaking, just like combustion engines.

It’s the water’s fault, not the kind of propulsion you’re using. All other things being equal, the boat’s drag increases exponentially as you try to make it go faster. Another way to put this: you need exponentially more power to go another knot faster.

For electric outboards we talk about watts, which is the metric unit for power. So the math is pretty simple. A 1 kW outboard (equivalent to 3 HP of combustion propulsion) will run at full speed for about an hour with a 1 kW hour battery. See how the math checks out?

At half throttle with the same outboard and battery, you guessed it: you’re draining the battery at about 500 W/hour, giving you 2 hours of running time. But you’re getting 3/4 of full speed. Lowering to 25% throttle gives you 4 hours of running time at 2/3 of full speed. Generally speaking.

The moral of this story is that with way less throttle you get way more distance with only a small loss in speed. Generally speaking, just like combustion engines.

I’d even say that range isn’t an issue any more, generally speaking, for small outboards. There more useful comparisons between electric and combustion are in portability, maintenance, and operating cost, which electric outboards have an advantage over.

What to expect from a small electric outboard

Electric outboards have quite a few advantages, which comes from not being held back by a combustion engine's 19th century mechanical legacy. Here’s what’ll be different than a combusting outboard:

Range

For pushing your tender or small sailboat, a small electric outboard is a viable replacement for an equivalent combusting outboard. In fact, electric is probably the better choice. My rule of thumb: assuming you have access to sufficiently convenient capacity to charge a 1 kW hour battery, how far are your daily trips?

• Less than 15 nautical miles (28 km) per day: Go electric
• 15-30 nautical miles (28-56 km) per day: Go electric, get an extra battery
• More than 30 nautical miles (56 km) per day: Go electric or combustion

Portability and storage

An electric outboard with its battery typically weighs a little less than an equivalent outboard. And there’s some flexiblity here: removing the battery drops an electric outboard’s weight by about 25-30%, making it even easier to carry.

An electric can be stored pretty much anywhere you’d store a combusting outboard, only you don’t have to worry about leaking fluids (which means there’s no limitation on the orientation).

Sound and smell

Nobody, not even you, will hear or smell you coming or going.

Flexibility

Electric opens up new features that are impractical with combusting outboards. Mobile apps, remote controls, and other accessories are available.

Maintenance and repair

You’ll be saving a lot of time on this because there’s practically nothing involved beyond keeping it clean. No oil, filters, or spark plugs to change, no gummed up carburator to clean, no water impeller replacement, no freshwater flushing.

When something breaks down, repairs are much easier than combusting outboards. With no cooling, exhaust, or fuel system, there are way fewer parts, and their interactions way less fidgety. That means you need fewer tools, practrically no messy solvents and lubricants, and less expertise to repair an electric outboard.

Recharging

You have more choices than combusting to top up. On board there's the alternator, solar, or wind. On shore, you can plug into a wall.

Of course, make sure you have the capacity available to top up between usage.

Cost

The purchase cost ranges from a little less to quite a bit more than a comparable combusting outboard.

ePropulsion is the value leader here. Their outboards are less expensive than a comparable outboard. Mercury is about the same. Torqueedo is more expensive.

Small combusting outboards cost relatively little to maintain and operate compared to their big siblings, but electrics are even cheaper. Expect to pay less in both time and money.

Mercury Avator 7.5e

Mercury is currently the only major conventional outboard manufacturer to sell electric outboards under its own brand. (Yamaha acquired Torqeedo in 2024. We’ll see how that goes.)

The biggest criticism for this outboard (with battery) is its weight. Curiously, it’s heavier than an equivalent combusting outboard.

On the plus side, Mercury backs up their Avatar outboards with a 5 year warranty, more than ePropulsion or Torqeedo.

The transom bracket is semi-permanent, and the outboard itself drops easily onto it. So when you transport this outboard, you’re only carrying the outboard and battery. This saves a bit of weight when carrying it, but it’s still a heavy outboard at 54 lbs/24.4 kg.

Horsepower equivalent (claimed): 3 hp

Shaft length (inches): 15, 20, 25

Weight with battery (lbs/kg): 15-inch: 54/24.4

Integrated battery capacity : 1 kWh

Carrying handles: tiller acts as carrying handle

Transmission: forward, "neutral", and reverse

Warranty (years): 5

Manufacturer site

ePropulsion Spirit 1.0 Plus 1 kW

This is the value electric outboard. It’s also the lightest in weight. For a smaller price you get less outboard and a shorter warranty than Mercury.

An innovation that ePropulsion offers that the others don’t: hydrogeneration. The Spirit 1.0 Evo 1kW can recharge itself under certain conditions. This variant costs more than the Spirit Plus, but makes sense as an outboard for your sailboat if you sail for long periods or you’re far from other charging sources.

Horsepower equivalent (claimed): 3 hp

Shaft length (inches): 15, 20, 25

Weight with battery (lbs/kg): 15-inch: 42.6/19.3

Integrated battery capacity : 1 kWh

Carrying handles: nothing built-in

Transmission: forward, "neutral", and reverse

Warranty (years): 2

Manufacturer site

Torqeedo Travel S

Torqeedo is the first major entrant into useful portable, electric outboards, having launched in 2006. In other words, they have the most experience. Yamaha seems to agree with me by acquiring them in 2024. Yamaha itself is no slouch in marine power, so hopefully they’ll give Torqeedo the backing for more interesting outboards in the future.

Torqeedo takes owner serviceability a little more seriously than Mercury or ePropulsion. No manufacturer, combustion or electric, provides downloadable service manuals for their outboards. But at least Torqeedo lists and sells parts online. And they have a few service videos for owners. Mercury and ePropulsion, like all other outboard makers, make you go to the retailer for parts and service.

Horsepower equivalent (claimed): 3 HP

Shaft length (inches): 15, 20

Weight with battery (lbs/kg): 15-inch: 44.4/20.2

Integrated battery capacity : 1080 Wh

Carrying handles: nothing built-in

Transmission: forward, "neutral", and reverse

Warranty (years): 2

Manufacturer site

More about small outboards

At your service

Humbly yours,

Marc, Supreme Purser