Electric Boat: The Solar Explorer

Marine grade structural foam and epoxy impregnated glass fiber are combined with other light weight materials achieving higher strength that other more exotic methods and materials. The process does not employ molds therefore design is not restricted from improvement or modification, yet is able to compete commercially with mold production techniques.
Patented process IbeamArray®  achieved super strong light weight 14′ x 8′ tri hull with dry weight of only 100kg (220lb) stronger than carbon fiber of same mass.

CALB Lithium Ion 100Ah prismatic cells of Iron Phosphate chemistry 10 per hull give nominal bus of 32 volts with total capacity of 6.0kWh @ 68kg. Cell are rated for storage and operation environment of -20 to 55degC. An impressive advertised cycle life of >2,000 @80% means a better performing battery with longer life than lead acid with half the weight at same cost.
New CA100 cells are available globally at ~US$130.

Downside to Lithium Ion is the requirement for more sophisticated battery management. Explorer has shown the CALB cell to be robust and reliable. The integrated control system manages charge and discharge, nominal cycle is restricted to 10 – 90% which increases cycle and storage life.

Other chemistries used by the auto industry for EV models have better KWh per kg ratio, a critical factor for motor vehicle range. However the safety factor is reduced and there have been several reported incidents of battery fire. Auto manufacturers claim causes of impact and accident. However there have been NO reported fire from an Iron Phosphate battery. A failed cell may cause elevation of temperature but not to the point of structural damage of the cell case or ignition.

Charging is simply a matter of plugging in a normal household electrical extension cord from a 120vac outlet. In Europe the system is fully compatible to 230v 50hz charge supply. Charge time from fully discharged battery is normally 6 hours.

Maximum cruising speed is 7kts (12kmh), nominal speed 3.5kts (6kmh) @ 300watts, giving a range without sun of 120km. At lower speeds range of 300km can be achieved without sun. A typical day out on the water consumes less than 30% of battery capacity. For casual cruising in sheltered waters, several days exploring waterways without thinking about battery charge is normal.

Solar panels are semi flexible 100w peak using back contact cells by Sunpower 20% efficient. Explorer is currently fitted with 4 x 100w panels and so a total peak solar energy of 400w. In practice at latitudes such as Florida USA a typical maximum output from the panels is 300watts, enough to push the craft along at an impressive 6kph. It could also charge the fully discharged batteries in 20 sunny hours. Panels are adhered to the hull and wiring is hidden and sealed under the panels. Cells are fully encapsulated and are designed for light foot traffic.


Torqeedo drives are modified Travel 1003. The 1000 watt motors are mid generation with infinite speed variability and better than 48% overall drive efficiency. Current Travel models also claim silent running. Each hull is fitted with 100deg rotation pod positioned with electric actuators. Steering in manual mode is by traditional steering wheel however 4 second press and hold of manual button will introduce thrust steering where steering wheel will vary motor power to achieve more accurate heading control. Auto pilot also employs thrust steering. In Maneuvering mode steering and thrust is applied to produce transverse and rotational thrust as required. 

Seating is for 2 persons with adjustable reclining and longitudinal position. Seats may be reclined flat to form a one man bunk.

Boat trim may be adjusted by seating position or positioning battery fore / aft.