WoodenBoat Magazine Reviews the Elco 9.9 Electric Outboard

The Elco 9.9hp Outboard Motor: Reviewed by Greg Rossel: Issue Number 247, www.woodenboat.com

Electric propulsion on land and water has been around for more than a century. The appeal is the same as it has always been: Electric motors are clean, powerful, low-maintenance, durable, vibration and odor-free, safe, and quiet. They emit no pollution and, as anyone who has ridden in a Tesla electric car can attest, electricity can be a pretty sporty way to get around.

That said, electric power historically has had stiff competition from petroleum-fuel engines. Gasoline and diesel are energy-dense, ubiquitous, relatively (and probably artificially) inexpensive, and the engines really do sound powerful. One wonders if a silent electric Harley-Davidson motorcycle would be quite as much of a crowd-pleaser as the famously throaty gas version.

Into this practical (and sometimes philosophical) arena of opposing technologies comes a line of new electric outboard motors from Elco that promise to compete head-on with the familiar brands petroleum-fueled models. It is not surprising that Elco has introduced such a motor; after all, they have been promoting electrically powered vessels since they produced 55 electric launches for the 1893 Chicago World Columbian Exposition. Elco has historically concentrated on electric inboard motors, but in recent years they began offering small outboards in 5-7 and 9.9-hp versions run on 48 volts, and on the drawing board they have a 15-hp and 25-hp version using a 96-volt system. 

The appeal of these motors is strong, and not just for the alternative-energy consumer. There is the promise of smooth running, reliability, and generally less service. Additionally, with more and more “electric power” lakes and reservoirs, a battery powered motor may be the best option for many to get out on the water. In a world where so much is going electric – be it automobiles, heat pumps, and full-home rooftop solar panels – an electric outboard is certainly intriguing.

Our 90-lb, water cooled 9.9-hp test motor arrived in Brooklin on a dank and murky afternoon. Outwardly, its appearance and controls could easily be confused with those of its traditional gasoline-fueled colleagues.

The difference lies under the cowl: Where one might expect pistons, cylinders, fuel injectors, and spark plugs, there is instead an electric motor and controller that senses load and torque. We tested it on a 15′ Jericho Bay Lobster Skiff (see WB Nos. 210 and 211).

Swapping the electric Elco motor for the existing 20-hp Yamaha gasoline engine was relatively straight-forward. The motor clamps onto the transom in the same manner as a gasoline engine, and is prewired with harnesses and connectors for attaching to the battery and shift-throttle – which is roughly the same size as the familiar single lever gasoline version. The shift-throttle unit is meant to be an exact duplicate of contemporary gasoline ones, but it took just a bit of finessing to get it to fit our test boats existing holes – through no drilling was required. A “suitcase of batteries” replaced the fuel tank in the boat, and a heavy electric cord sold in for the fuel line (more on all of this in a bit).

When we got underway, the experience was initially a it unusual. There was no sound of ignition at the turn of the key, nor was there the reassuring puttering of an engine at idle. Indeed, I wondered: “Is this thing really on?”

As I cautiously engage reverse by pulling the handle back, the motor sprang to life, backing the boat into the fog-shrouded harbor. The experience was more Toyota Prius than Tela: There was no sudden blast of speed when the throttle was opened, but instead a steady acceleration. The sound was different from what one would expect from an outboard motor – more the purr of a powerful sewing machine than the throaty rumble of hydrocarbon consumption. The motor was put through its paces, and it performed very well. There was, however, and at only a certain low-speed setting, a bit of “stutter” almost akin to a spark plug misfiring. The cause of this was unknown, although a follow-up conversation with Elco representatives suggests it might have been due to cavitation, and that adjusting the angle of the motor might have cured it.

The shifting was smooth and positive. Approaching a dock, the motor can slow to what feels like the propeller barely turning, allowing you to maintain a steady headway without engaging and disengaging the gears as is commonly done on a gasoline motor. When you arrive and put it into neutral, the motor again falls silent, like an electric automobile at a stop sign.

Aside from the motor one needs to have juice that fuels it. And with any electric vehicle, there is always concern about range. The motor will run either on conventional AGM (absorbed glass mat) batteries or on a lithium-ion battery pack that will be soon offered by Elco. The lithium batteries are packaged in a black waterproof “suitcase” not that much bigger than a carry-on piece of luggage, but heavier. The large pack weighs roughly 80 lbs. We used a 48-volt lithium pack in our test. It allows 100 amps per hour usage costs $4,200. A smaller version of the 5-hp motor costs $3,500 and weighs 65 lbs.

A “state of charge meter” (akin to a fuel gauge) is included on the suitcase, and an external gauge to mount on the console is available. The manufacturer claims one can expect to get 3 to 3.5 hours of running between charges if run at usual conditions – stopping, starting, cruising, and trolling. Using their battery charger, the recharge time is estimated at 4 to 8 hours. 

The projected life of the batteries can vary widely with usage and maintenance but at an expected 1,200 discharge-recharge cycles they will likely last 12 to15 years. The Elco battery packs are equipped with a safety feature allowing them to sense low voltage and shut down the motor. The motor can then be restarted but will only run at 75 percent draw. (It is worth noting that lithium batteries are affected by heat, and Elco recommends keeping the battery pack cool and out of direct sunlight.) To further exited range of operation, a second battery pack could be purchased or a small generator incorporated that would turn the vessel into a hybrid.

Elco claims that the motor is unaffected by the marine environment – either salt or fresh water. They have 350 5-hp versions in service with no problem. Approximately 30  percent of the units sold are used in salt water. With fewer parts than a gasoline engine, the reliability  of the motors is expected to be good. But should you buy one? the answer brings us back to the century-old question of competing technologies, practicality, cost, and philosophy. There is no question that the technology is time-tested and solid.

Is it practical? I think so. The motors will do everything that a petroleum fuel versions will do – in some cases, perhaps more, as there drive-train is more efficient. The motors can be used in waters that are off-limits to gasoline. There is little concern for vapor venting, and they can be installed in enclosed compartments.

The cost raises the same concerns confronted within one considers an electric vehicle, installing solar panels, or perhaps upgrading the house from kerosene lamps to electrical lights. (“Those dang wires and outlets cost a lot! We’ll never pay them off!). The price of the motors is indeed higher than conventional units of the same horsepower ratings: The 9.9-hp costs $4,804, the 7-hp $4,119, and the 5-hp $2,910. And then there is the price of the batteries. One has to put on a green eye-shade to work the numbers, and it comes down to short-term price vs. long-term cost. Where will the price of fuel go? Can you charge the batteries with your solar array? What are the projected maintenance costs, how long will the outboard last, and what is the resale value? And so on.

Then, we’re back to philosophy…another version of the stink-pots-vs.-sail argument. How do you feel about exhaust and the sound of power? How about the question of carbon footprint? And just what is it worth to cruise nearly silently up a waterway? For many, the extra price will be worth it.

Greg Rossel is a contributing editor for the WoodenBoat Magazine and an instructor at WoodenBoat School.