The first catamaran featuring the Molabo 48V inboard electric is on the water and attracting admiring onlookers in Auckland, New Zealand.
The Earthling E-40 Powercat is the creation of John McGettigan of Earthling E-Propulsion, who modified a hull design from Alan Cardawine of Asia Catamarans and assembled the boat’s serial hybrid propulsion system. (Serial hybrid means the propulsion is always electric drive with power supplied by battery. A diesel generator is used to top up the charge of the battery when necessary.)
In the Earthling E-40 there is a powertrain in each hull, consisting of the Molabo ARIES 50 motor, 2 lithium-ion 11kWh battery modules and a Whisperpower 8.5kW Genverter. Components can be cross-connected between the hulls for redundancy – engineer speak for back up.
With full battery charge the E-40 can travel up to 40 nautical miles (46mi/75km) at low speed, 30 nm (34mi/55km) at 8 knots (9mph/15kmh), and 20 nm (23mi/37km) at 10 knots (11.5mph/18kmh).
Altogether there is 44 kWh of battery energy available, which can be charged on shore, by roof mounted solar panels or the generators. The genset automatically kicks in when DOD (battery depth of discharge) is at 20%. It burns 2.5 litres of diesel per hour.
Molabo 48V ISCAD motors maximize output
Molabo was founded in 2016 to commercialize the innovative 48V ISCAD electric motor system (Intelligent Stator Cage Drive) developed by Florian Bachheibl and Adrian Patzak when they were students at Munich’s University of Federal Defense. The technology now has more than 50 patents registered worldwide.
The ISCAD maximizes mechanical power output per volt by using rods instead of copper windings in the stator of the motor. Forty-eight volts is considered ‘safe-to-touch’, so the ARIES 50 can be easily and quickly installed without high-voltage safety measures and training.
“It is a huge advantage that you don’t need high voltage safety measures” says McGettigan, “but the 50 kW drive from Molabo is just a really impressive product overall. Moving at 10 knots feels effortless, like sitting on a couch at home.”One of the reasons is that McGettigan optimized everything on the boat for maximum efficiency. The hull is made of core composite foam and carbon fibre inserts and weighs only 3.6 tonnes. The propellers are oversized – 600mm in diameter – and turn at only 400-600rpm.
This takes full advantage of the Molabo’s high torque and reduces energy consumption. The propellers are optimized for a 10 knot ‘sweet spot’ that uses 15kW – 7.5kW per motor. The rest of the power can be used when necessary, but the E-40 is not meant for speed.
As McGettigan told Alex Stone of Boating New Zealand, “I don’t like talking about speed with Earthling. Speed is inefficient, chews power and adds stress. This boat is all about working with nature. We really must become more comfortable being self-sustaining and energy efficiency is key.”
Controller integrated into motor
Another benefit of the Molabo 48V technology is the integration of the controller into the motor, a big space saver. That made installation and wiring much easier in the confines of the catamaran pontoons. The ARIES 50 also connects easily with all of the boat’s other components.
McGettigan has developed a proprietary system called E-Thos that monitors and controls navigation, charging, water levels, kitchen appliances and more. The data is all visible on a touch screen in the helm with visual alerts so you can recognize instantly if anything needs attention.
This ties in seamlessly with Molabo’s MolaLINK that allows engineers in New Zealand to quickly and easily communicate with Molabo headquarters in Germany for remote service.
As for creature comforts, the Earthling E-40 has a full galley and everything else needed for a pleasant day of island hopping and overnight stay. There is a queen size double berth with ensuite head and shower and another wide single berth. John says he had 14 adults on board for a New Year’s Eve cruise, with no worries.
“A winner straight out of the box”
He told WhisperPower’s CEO Roel ter Heide that he aims to “provide a limited production of two yachts a year. We won’t change anything as she’s a winner straight out of the box. The hulls could be extended to between 50 and 60 feet with the same solution, but 40 feet is a very user-friendly length and spacious too.”
“This boat is so quiet and sails so nicely, we are sure leisure boat owners will love it. We’re also looking at the ecotourism market in places like Australia’s crocodile and bird sanctuaries. The two-strokes typically there are very intrusive for the environment and the Earthling is an ideal solution.”
Photo Credits: Roger Mills/Boating New Zealand