ePropulsion: Taking Electric Outboard Motor Technology to the Next Level
December 28, 2020
The Hong Kong University of Science and Technology sits in Hong Kong’s Clearwater Bay, so it’s perhaps no surprise that four of its graduates—engineer Danny Tao and three of his classmates—spent much of their spare time involved in water sports and marine protection projects; or that they were then inspired to found a company that’s all about developing eco-friendly electric propulsion systems for the marine market.
Today, their company, ePropulsion, is leading the charge (pun intended!) in electric drives for marine use. The company aims to be the global leader in marine electric propulsion systems and services, providing quiet, high quality, low maintenance and, most importantly, eco-friendly, electric outboard motors—and their success so far suggests that’s an achievable goal. Yesterday, Hong Kong; today, Europe, with offices in the UK and Germany; tomorrow, the world!
Any electric motor will have advantages over petrol or diesel; there’s no risk of leaks or smelly, toxic exhaust fumes. But ePropulsion’s systems use direct drive. That means there are fewer moving parts—which in turn means fewer failures, less maintenance, less vibration and less noise—and also more efficient, as the propeller takes the power directly from the motor without any intervening elements, such as a gearbox. This along with other technologies they’ve developed, such as closed-loop liquid cooling, is helping them achieve their mission to make boating more accessible, reliable and sustainable—and as the world turns its back on fossil fuels, that success is timely.
Our look at ePropulsion’s innovative products begins with their flagship offering: The Spirit 1.0 Plus.
The Spirit 1.0 Plus
The Spirit 1.0 Plus is an industry-leading electric integrated outboard motor and battery with a 28 × 14.7 cm/11 × 5.8 in propeller, recognised for both its outstanding performance and reliability.
The lightweight battery, weighing just 8.7kg, has a huge capacity—1276 Wh from the 24 lithium cells—and a final charging voltage of 52.2V. An advanced battery management system means you get peak performance, and impressively, it retains 80% capacity even after 800 cycles of 100% DoD (Depth of Discharge). A safety latch locks the battery securely in place, but should it fall overboard when not in use, don’t worry—it’s designed to be unsinkable!
It also has a user-friendly battery handle, making it easy to transport. Battery replacement is simple and takes just one minute, while charging only takes three and a half hours on a fast charger and eight and a half hours on a standard.
The 1 kW motor, weighing just 10.6kg, runs at 55% overall efficiency—far superior to a combustion outboard motor—and can deliver propulsive power equivalent to a 3 HP petrol engine. Direct drive makes it both more efficient and more reliable, as there are fewer moving parts than in a conventional motor, and it uses field-oriented control (the most efficient way to drive electrical motors using orthogonal applied current).
Petrol outboards in the 2.5 HP to 5 HP range have a run time of less than 45 min at wide open throttle (1000W). The Spirit 1.0 Plus offers 75 minutes, powering a 12ft tender at 6.2mph for 7.75 miles (at full throttle); reduce your throttle to 25% (250W), and you will get 5 hours’ running time at 4.4mph, giving an impressive range of 22 miles.
Versatility and Convenience
The Spirit 1.0 Plus can charge from solar panels (max 180W) or a 12v auxiliary output, and its 48V operating voltage allows it to work with an external battery to extend the range (either from a third party brand or ePropulsion’s original E-Series LiFePO4 batteries).
It requires no servicing or special preparations for winter weather, and it’s also amazingly quiet, with a maximum noise output of just 55dB. The tiller folds down for easy, compact stowage and three shaft lengths are available to suit your boat type: extra short (for tenders), short and long. Control is by tiller or remote, and there’s an integrated display.
The Spirit 1.0 Plus also offers 360° tiller steering and stepless forward/reverse control.
Safety and Reliability
The Spirit 1.0 Plus is robust and built for durability, passing an 83-day continuous running test with flying colours. A magnetic kill switch instantly stops the motor in emergencies and there’s also a propeller collision emergency stop and a protective beach mode. There’s built-in overheating protection and IP67 standard water ingress protection too.
The power connector is made of high-quality stainless steel, the transom mounting is reinforced, and a built-in display with real time information shows battery level, input power and voltage.
The Navy Series
If you have a bigger boat, then it’s time to call in the Navy! ePropulsions’s industry-leading 48V Navy Series direct drive motors are up to the task. The 3 kW Navy 3.0 can comfortably power a 3-tonne boat and the 6 KW Navy 6.0 is the most powerful motor ePropulsion currently offer, ideal for boats up to 6 tonnes.
Again, these motors are comparatively lightweight, with the Navy 3.0 weighing in at 21.6kg and the Navy 6.0 at just 27.8kg. Both motors sailed (pun intended) through their 83-day continuous running test and are maintenance-free, with no winterising required. They can be used with ePropulsion’s E-Series batteries or a battery of a different brand, or alternatively, they can be charged from solar panels.
The wireless Navy remote controller is designed to control both forward and reverse speed. It can replicate the features of a Navy tiller handle except for steering. The Navy tiller handle is designed for stepless forward/reverse speed and heading control. Its 105° rotatable grip gives excellent manoeuvrability. Thanks to integrated GPS, the LED display shows range, speed, time, and energy consumption. Both the remote controller and tiller handle have a solar panel that provides power for the built-in battery. You can also charge the control from your motor via a cable. Again, there’s also a side mount control option alongside a 3.2″ real-time display to mount in the cockpit.
Both Navy motors use field-oriented control, offer the full range of ePropulsion safety features, and are available with long or short shaft options to suit your vessel. The tiller can be removed for convenience. The Navy 3.0 provides 51% maximum overall efficiency and uses water cooling; the Navy 6.0 provides 57% maximum overall efficiency and uses closed-loop liquid cooling.
EPropulsion’s Pod drives are an efficient way and space-saving way to power your sailboat or motorboat, and it’s easy to identify which model you need: the Pod 1.0 offers fixed propulsion for small boats up to 1 tonne, while its big brother, the Pod 3.0, is suitable for boats up to 3 tonnes. The Pod 1.0 offers an impressive 55% max overall efficiency and the 3.0 offers 51%.
The Pod Drives are 48v systems that can be used with ePropulsion’s Spirit Plus, E-Series batteries or batteries from another brand, and they use efficient field-oriented control. They’re maintenance free, need no preparation for winter and passed their 83-day running test with ease, so you can be confident in their reliability and durability, too.
Both models are lightweight (the Pod 1.0, 6.2kg and the Pod 3.0, 12kg) and designed to minimise drag. They’re also vibration-free and quiet, with a maximum noise level of 60dB. Wireless or wired remote control is available and a solar panel powers the built-in battery, although it can also be charged via a cable connection to your motor. However, boat owners can also choose a side mount control. There’s also a 3.2″ real-time display to give you range, speed, input power and battery capacity information, which can be mounted easily in any cockpit. Safety is assured by ePropulsion’s added features: an emergency magnetic kill switch (the lanyard can be clipped to your wrist or life vest, and will stop the motor instantly if removed), IP67 standard ingress protection, water cooling, a propeller collision emergency stop, reinforced mounting, a low battery indicator and protection against overheating.
48V E-Series Lithium Batteries
ePropulsion’s E-Series batteries use high-end technology but are extremely cost-effective, costing around 40p/Wh. They’re 70% lighter and use 50% less space than conventional acid batteries.
The E-Series range of 48v LiFePO4 batteries includes the E40 (2048Wh), E80 (4096Wh) and the E175 (8960Wh). Their modular design means they’re all suitable for a parallel connection system of up to 16 packs, and they’re built to last, with an estimated battery life of 3000 charging cycles at 80% DoD. They’re also very safe, as they will not overheat, not catch fire (even when punctured) and not pose any risk to health or the environment, as the cathode material they contain is non-hazardous.
These high-performance batteries will power any of ePropulsion’s electric outboard motors and Pod drives, and can also be used with other types of 48v systems, including home or commercial solar systems. However, their shockproof and waterproof credentials make them ideal for life on the ocean (or river!) wave.
Versatility, Support and Sustainability
The versatility of ePropulsion’s products and the breadth of their range means they have an electric propulsion solution for most work boats, fishing vessels, dinghies, tenders and leisure boats—and they’re a boon for keen anglers in those countries where fishing lakes are increasingly becoming electric-only. ePropulsion even now offers a propulsion solution for kayaks called the Vaquita. They can also provide bespoke solutions to boat builders and designers wanting to integrate electric drives into their new craft.
The company owns their own manufacturing plants and this, together with careful procurement, gives them control over the whole process from design to delivery, allowing them to maintain the highest quality standards. Those standards are maintained after sale too, as ePropulsion have a strong commitment to continuing customer support. Judging by the company’s Instagram account, those customers are extremely pleased with their ePropulsion systems, enjoying their performance and loving the quietness of the motors. That quietness makes these motors ideal for fishing trips, and for nature lovers who want to get closer to wildlife without causing alarm and in a way that respects both freshwater and marine ecosystems.
ePropulsion outboard motors are also at the heart of many sustainable projects. People keen to live an eco-friendly, off-grid life are using them to power their houseboats, and an ePropulsion motor is fitted on the solar-powered boat used for the clean-up program in Elizabeth Quay, Perth. They’re also used on rental fleets serving Lake Constance and Lake Thun in Switzerland, helping to keep these beautiful waters and their glorious surroundings free from pollution.
“By providing the top-notch electric outboard motors and pod drive motors that are quiet, efficient, emissions-free and reliable, we're dedicated to improving and enriching people's boating experience whilst protecting the living environment for marine life," the company explains.
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