Integrel, On-board energy management: traditional generator goodbye

Integrel Solutions, a company specializing in the development of innovative solutions for on-board energy management, offers two “plug and play” systems designed for medium-sized sailboats. These are high-power, very compact alternators that can be mounted on new and retrofit units.

From Integrel Solutions, two integrated systems that eliminate the need for fossil-fueled generators. The first, Integrel E-Power 9 SE, is an automated system for power generation, storage, conversion and distribution. The second, Integrel E-Drive 15 SE, also adds electric propulsion to these functions, converting a conventional endothermic system into an hybrid configuration. 

These systems, designed to be installed on both new and retrofit units, provide advanced integration between generation and energy consumption, making them particularly suitable for medium-sized sailing vessels.

Underlying both solutions are high-power alternators developed by Integrel Solutions’ R&D department. They feature a compact design and simplified installation (they do not require through-connections or separate cooling systems since they are air-cooled). These alternators work in synergy with 48V lithium battery banks, providing high energy density and short charging times.

We discuss this with Diego Volpi, general manager of Power Group, Integrel’s distributor for Italy. 

E-Power, advanced energy generation

Integrel E-Power 9 SE harnesses the boat’s main engine for power generation. This system is based on a high-efficiency alternator that, through dynamic power management, optimizes production while minimizing fuel consumption and emissions. With a generation capacity of up to 9 kW, power is stored in 48V Mastervolt lithium batteries. For twin-engine boats (such as catamarans), dual installation is provided, doubling power generation accordingly.

The system is compatible with the main models of marine engines mounted aboard sailboats (Volvo, Yanmar, Nanni, Beta, Vetus, Cummins).

«Integrel has succeeded in creating an extremely efficient, high-power alternator with very compact dimensions, a key aspect aboard medium-sized sailboats,» explains Diego Volpi. «The alternator is mounted on the front of the engine and effectively takes up no additional space in the engine room. It weighs only 40 kilograms to which the weights of the batteries must then be added, but compared to a generator, they can be placed in various places on the hull, so space and balance are optimized.»

How It works
Integrel generates electrical power using a high efficiency, high-output large-frame alternator (OEG). It is belt driven from the PTO of the main propulsion engine and is typically installed in the same physical space as a conventional second alternator. However, unlike a conventional alternator, the power output and voltage of the Integrel OEG are actively managed to ensure that propulsion is always prioritized and engine loading is optimized. 

Whilst the main propulsion engine is running, it produces a variable voltage, variable frequency threephase electrical output which is passed to a custom designed Controller. A high-quality bridge rectifier within the controller converts three-phase power to a precisely controlled DC output. The DC output is electronically limited to 9kW/170A at a nominal 48 volts. A relatively high DC voltage helps to reduce losses in the OEG and keeps cable size, cost and weight to a minimum. 

DC power from the Controller passes to a 48 volt power busbar where it is distributed to the vessel’s electrical consumers including: DC-DC converters/chargers used to power appliances connected to 12V / 24V house batteries; AC inverters to power mains appliances at 110V/220V including fridges, freezers, ovens, hobs, etc; Heavy DC loads such as 48V bow thrusters, winches, and air conditioning (saving weight, cost and complexity compared to powering these items with AC inverters). 

Any power not used directly is stored in a bank of 48 Volt batteries. Integrel exploits the fact that there is a significant power gap between the optimum efficiency load line of an engine and the load applied by the propeller (the green and blue lines respectively in the diagram 3). The generator is used as a precisely managed variable load in addition to the propellor load to operate the engine at or near optimum efficiency. 

Integrel monitors throttle input, so that in the event full engine power is needed for propulsion, the system instantly powers down. As soon as stable engine RPM is restored, Integrel resumes full power generation

But what is the big difference from conventional alternators? «Integrel has created an ultra-high-power alternator with minimal size and weight», emphasizes Volpi «Additionally, its advanced control electronics stabilize voltage and maximize available power while reducing engine impact.»
Integrel automatically charges the storage battery bank whenever the engine is running, unless the batteries are already fully charged.
Through a stand-alone display at the helm station, the user can manage the system: he can unhook Integrel E-Power 9 SE if he needs to have maximum engine power, or activate the “Full Generator” function to have the generator running at full capacity. The display provides information on the status of the system, from the power produced, to the charge level of the storage batteries and other battery banks on board.

Regarding charging times, the following is the data provided by Integrel. A 10 kWh Lithium battery bank charges from below 20% to above 90% in about an hour from a single Integrel system. A 30 kWh lithium battery bank charges from below 20% to above 90% in about two and a half hours from a dual Integrel system.
While motoring, in about two hours will typically charge the battery bank to above 80% (depending on the size of your battery bank).
Integrel is developing a new version of the 15 kW E-Power, which will not be keyed to the motor but mounted on the shaft line. «The goal is to come up with a product that is also suitable for motor boats, so with higher power and torque.»

E-Drive, combined propulsion and generation
Similar to E-Power, the Integrel E-Drive 15 SE system also employs an alternator motor. However, this version is a permanent magnet model, capable of both generating power and providing electric propulsion. Installed between the engine and transmission, the system delivers up to 20 hp of electric power and generates up to 15 kW of energy. On twin-engine boats, such as catamarans, two units can be installed, doubling both power and generating capacity.

«A strength of this solution is its universality: it is compatible with the main engines mounted on board boats. Integration with the transmission requires an axial length increase of only 150 mm. This gives shipyards great flexibility, allowing them to offer hybrid or traditional configurations without redesigning the engine room. In the case of retrofit it is usually possible to find those 150 mm needed to mount it.»
In generation mode, with the diesel engine running, Integrel E-Drive 15 SE works on the same principles as E-Power, but generates about twice the power.

In propulsion mode, an integrated clutch allows the thermal motor to be decoupled, enabling electric-only operation. On the dashboard, the system provides an interface that manages thermal and electric modes with the same throttle. From the provided display, the different modes of system operation can be selected: generation, pure electric, or hybrid. When the hybrid function is selected, the system runs in electric at low engine rpm and automatically switches to thermal when the rpm increases. «The 20 hp provided by the Integrel E-Drive 15 SE is an excellent complement to propulsion. It delivers enough power for maneuvering in and out of harbors and bays, short-distance navigation, or operating in areas where internal combustion engines are restricted», Diego Volpi ends.

by Paola Bertelli