How our hybrids work

Basic Operation:

With the engine turned off and the gearbox in neutral the electric motor can drive the propeller using energy from the battery bank. Speed and direction is set by the controller.

When the batteries run down, (or high propulsion power is required), the engine is started and the gearbox put into drive. At this time the controller senses the engine is running and switches the motor to generate mode. So the engine now drives the propeller and the motor acts as a generator to recharge the batteries.

When the batteries are recharged you can stop the engine. The controller senses the engine has stopped and automatically switches back to electric drive mode.

The engine does not need to run all the time and when it is on it is substantially loaded by the propeller + generator. The engine running at higher loads gives us greater efficiency,

6 operating modes of a Parallel Hybrid

    • Conventional propulsion with hybrid completely disabled.
    • Engine is able to drive through the gearbox to the shaft. Does not require any hybrid components to enable propulsion.
    • Engine is off and the electric motor is driving the propeller with energy from the battery bank.
    • Both engine and electric motor drive the propeller. Although motor boost is theoretically possible we do do not implement in most of our applications.
    • General advice is to size the engine for maximum power requirements and to have the motor/generator in generate mode when ever the engine is running.
    • The engine is driving the propeller shaft, via the gearbox, in the conventional way.
    • At the same time the Generator is engaged and providing an extra load on the engine.
    • Energy is extracted and stored in the battery bank. The controller is able to provide multi region charging of the battery bank (this patented technology) and can accommodate any battery technology.
    • At higher engine speeds, when the propeller starts to substantially load the engine, the hybrid generator backs off so as not to overload the engine.
    • At very high loads the hybrid generator tuns off completely allowing the engine to supply its full power to the propeller.
    • The shaft clutch is open and the propeller disconnected.
    • The engine and hybrid generator can now operate in stand-alone mode.
    • Useful if at anchor or in harbour and the generator is required.
    • In some cases (inland barges) it is better to achieve stand-alone operation with a boost alternator bank.
    • This can run with the gearbox in neutral and will boost hybrid generation when underway and at low engine speeds.
    • Applicable only to sailing craft. When under canvas the propeller can be allowed to free wheel.
    • The controller can then have the generator extract energy from the spinning propeller to provide charge back to the battery bank.