Ideal power generation
Ideal power generation should be efficient (also at low speeds), low drag (preferably no drag when not regenerating), easy to use (automatic) & suitable for various propeller types.
- The motors need to be braked in order to create energy
- There are several propeller technologies on the market and many different types of boats
- Energy needs to be stored in high capacity
How does the system create energy while sailing?
The hydro generation or “creating energy while sailing” function is an automatic feature in all Oceanvolt motors. This feature is activated by pushing the button on the Oceanvolt displays for 5 seconds. The display will automatically switch to regeneration mode showing the current generated power, RPM and time until the batteries are fully charged. With a folding propeller the motor kicks the blades out and centrifugal force combined with the motor controller keep the blades open. The motor controllers tune the system actively at 10 Hz which prevents the blades from closing (too much braking would close the propellers). This is continuos monitoring, the system will adjust the propeller RPM depending on the boat speed. The system shuts itself down if the battery is fully charged or the boat speed is too low for efficient hydro generation.
How much energy can the system create?
You can create up to 4000W. This will recharge your batteries. Complemented with solar power and shore power, there is almost no need to use a generator while sailing. The below graph shows the regeneration power of one of the motors on the SIG45 catamaran.
The Oceanvolt systems are optimized for either 2 or 3 blade Flexofold folding propellers & Gori Propellers. Other folding propellers can also be used but they provide 30-50% less propulsion and regeneration power. The highest regeneration power is gained with fixed blade & adjustable pitch propellers and also with dedicated systems for hydro generator use, because they allow using a higher pitch/dimension propeller.
At 5-7 knots the regeneration power with a folding propeller is about half compared to fixed and adjustable pitch propellers. Folding propellers provide low drag due to partially opened blades. A 15 inch 3 blade folding propeller will slow the boat (Maestro 40, 6 tons) about 0.1 knots at 7 knots of speed in regeneration mode. The regenerating feature is extremely suitable for catamarans, because twin motors means double the energy. Catamarans are also faster which means that the regeneration power is higher. If the Oceanvolt motor is used only for hydro generation and not for propulsion the power boost gained from using a higher pitch propeller dedicated for regenerations is about 20-30%.