Frequently Asked Questions - Faq
Here are some questions answered
What is Sailcharger?
Sailcharger is a 150mm, 3-blade, propellor hydro turbine (water driven) with adjustable blade angles integrated with a submersible low RPM alternator to produce electricity from the motion of the boat while sailing.
How does it work?
As the boat moves through the water the hydro propellor of the sailcharger is forced to rotate by the water passing. The rotational force drives the shaft of an electrical alternator that converts the motion of rotation into electric current. The current is rectified and regulated and fed to the battery bank of the boat where the energy is stored by the chemical process of the battery.
How is it used
Sailcharger is a submersible unit with alternator and propellor turbine integrated. It can be mounted in various ways. Either sailcharger is towed in the flexible towing cable attached behind the boat or mounted on a support similar to an outboard engine.
At what speed does it start charging
The speed when the alternator starts charging depends on the blade angle. If the blade angle is small the turbine will make more turns per distance traveled and output voltage that is proportional to the RPM will then be equally higher.
The practical speed is appr 4 knots. Please the datasheet for more information
Does it work for slow boats?
Speed can reversibly be converted to height - "From what height an object has to fall to reach the same speed". It is also equavalent to static water pressure at the bottom of an aquarium with that equivalent height.
Hence, 3 knots is equal to a water pressure of 12 cm, 4 knots = 21 cm, 5 knots = 34 cm, 6 knots = 49 cm and 7 knots = 66 cm.
That explains why there is so little energy at 3 knots. It is the energy available from water flowing out of a hole in the bottom an aquarium only 12 cm deep whilst at 7 knots the flow is equal to the aquarium being 66 cm deep. At 12 cm depth the propellor placed in the hole will be slowly paddling but with water coming out at 66 cm depth there will be an exploitable inferno.
That is also explains why hydro power dams are more than 12 cm in height
However - as seen from the figures sailing at 6 knots is the same as owning a waterfall with a head of 0.5 meters. That is good news! No permit needed - it is your boat - just install Sailcharger.