Energy management

Energy managament In general, electrical propulsion trades routine diesel maintenance for a level of vigilance toward the boat's electrical system that's probably new to most operators. The system includes not just the drive unit but also the electronic controller, a battery bank, power distribution buses, and a shore-power battery charger. One can still use every piece of equipment imaginable, but not at the same intervals or in the same occasions that one would use them while running a diesel engine.



There are four sources of energy available for a hybrid sailboat:

  • Shore power
  • The regeneration from the electric wheel
  • Wind generators
  • Solar panels

While docked at a marina, the boat will be recharging the energy storage. While at anchor and underway, the electric wheel may be spinning when there are any currents and that helps load the system. Wind generators and solar panels will help slow the draw from the system as well as help supply energy for low-consumption applications, like lights and electronics. Still, one can’t pretend that there is a genset on board, so there would be some sensible rules the system will adhere to:

  • Some systems will be turned on only while docked at a marina, like underwater lights.
  • Some systems are used only while underway with the energy level very high, or while the motor is regenerating or while docked: dish washer, microwave, cooking range, entertainment systems, stereos, coffee maker, some of the interior lights, some of the outside lights, hair dryers, surround sound system, ventilation fans, trash compactor, electric cooking at the cockpit, windlass, washdown pumps, courtesy lights.
  • Some systems are meant to be used continuously or at least have energy available to them at all times: refrigerator, freezer, some communication equipment, navigation lights, and bilge pumps.
  • And some systems will be on all the time, but if the energy reserves fall below certain limits they will be shut off and used only when very necessary, like some navigation electronics, some communications, etc.
  • Finally, some equipment will be operated when necessary even if the energy level is very low because there are very good reasons for it, like the bow thrusters, or the VHF radio.

Let’s not forget that even while using a diesel generator, energy is not unlimited. No matter how much diesel one loads before departure, once spent there is no way more diesel can be obtained in the middle of the ocean. A diesel-based boat has to go back to a marina to refuel. In an electric-based one energy is always being generated again and stored, so even if the boat has to motor ahead for a long period and draws all the energy it can reasonably do and enters “rationing” mode for a while, at the first occurrence of winds the system starts to recover on its own.

There is no such a thing as an average boat. Some have shore-side power and permanently connected battery charger at their slip, while others cruise and anchor out for months at a time with little or no engine-running time. Some have auxiliary generators running 24 hours a day, keeping the boat’s batteries constantly topped off, while others have solar panels and wind generators providing intermittent sources of power. No two boats – even identical production-line boats – end up with the same equipment, experience the same usage, or have the same electrical needs. But we can think of no situation more demanding and improbable than a cruising sailboat in long passages, left to its own devices to generate and/or store all the energy it needs to perform its functions.

Climate control

The hatch on top of the aft stateroom will have a sliding screen and sliding enclosing like most hatches in modern boats. The hatches have double sliding panels that close them, one with thermal insulation, the other just a screen.

The companionway will also have thermal insulation as well as the entire structure around the pilothouse. The same air conditioner that supplies the salon has ducts that take forced air to the pilothouse, when opened.

The main stateroom must have an emergency hatch to the garage or to the outside. If to the outside, it will have the same features as the aft stateroom’s hatch.

In general this design is very “closed” with few openings and very efficient thermal insulation all around. An air quality system will monitor the air quality in general and a forced air ventilation system will keep the environment clean. The air conditioning, heating, and ventilation systems of each stateroom and the saloon are totally independent. That will permit to save energy by shutting off the system when nobody is using a compartment.

Probably the most challenging aspect in a boat without a diesel on board, the heating system depends greatly in the efficiency of the insulation, which will be the most efficient available today. The heating system will use the warm air generated at the engine room by the electric engine and electrical equipment, and will be complemented by the air conditioners in each compartment.

Energy conservation

Some ways to reduce power consumption:

  • It is possible to reduce air-conditioning with proper awning, wind scoop, and ventilation design.
  • To optimize refrigeration the icebox and refrigerators muse be extra insulated, drains and seals checked for heat infiltration, and water-cooled condensing units.
  • The radar must be turned off or put on stand-by when not necessary.
  • Cabin lights must be turned off automatically when not needed and fluorescent lights used instead of incandescent bulbs.
  • Anchor and navigation lights are replaced with LED lights, and a photoelectric cell added to the anchor light.
  • High-energy fans may be replaced with lower-energy units.

Water conservation Water conservation

There are simple measures and protocols to be followed regarding the use of fresh water:

  • Both showers have a mechanism that senses if there is someone actually in the shower to allow the water to flow to the showerhead.
  • Vacuum flush systems use to flush a fraction of the water required by regular systems, then also eliminating the odors caused by the use of sea water to flush, and increasing substantially the capacity of holding tanks.
  • The toilets reuse the water from the showers.



Multiplex wiring system

These Digital Control Systems feature the latest in digital multiplex technology, creating a safer and fully configurable control system for the marine environment. With numerous advantages to both the marine manufacturer and the end operator, these systems truly define a revolution in switch technology. While providing flexible systems with attractive aesthetics, they also simplify and enhance the end operator's switching environment.

Key benefits of a multiplex wiring system:

  • Simplified operator control, comfort, and safety.
  • Ease of Installation.
  • Reduced labor installation time.
  • Simplified wiring resulting in [estimate 40%] weight reduction and space savings.
  • Ease of serviceability and troubleshooting.
  • Programmable and expandable switching functions.

Voltage monitoring software and battery drain protection are part of the system, and can be assigned to individual buttons on the Digital Control Module. This feature minimizes the chances of the voltage level dropping to a non-operational low level, by shutting down low priority circuits during low voltage situations. The software can automatically turn OFF components at a specific voltage level. Each circuit can be assigned one of three levels of battery protection. By assigning a priority level to each circuit, the system knows which electrical circuit to turn OFF, and in which order, when the battery voltage drops below the programmed Low Voltage Level. Priority Level One Circuits will always remain ON.

The system will also feature dedicated bilge pump circuits to protect them while at the same time ensuring that those pumps will work even when the system is shut down. Individual circuits can be controlled with multiple switch buttons in multiple locations. The system detects when a circuit breaker trips, logs the occurrence, and warns the operator.

The main energy bus will be circular instead of longitudinal, so a lighter wire can be used and there will be two paths of energy to every point of the bus. In the very unlikely event of an interruption of the bus cable all equipment would still receive energy, though with less capacity so the operator would then turn off non-essential equipment while the emergency is corrected.