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Solving the Power Problem with Catamarans – No Genset

Catamaran at night no genset

Frugal, Moderate or Bold Energy User?

A 50-55ft Catamaran with 2 people will use 10-20kWh of energy per day. This may be a combination of gas and electric. If it's all electric as the trend is with induction cooktops and combination air fryer/ oven, then it may be closer to 20kWh of electrical energy per day.

3kW of solar in the aft region of the boat free from general sailing shadows will yield 15 -18kWh in good weather in summer.

The challenge is the 20% of the time when solar yield is poor. Fortunately when the yield is poor, the skipper may be relocating with the engines running. It's during this time, there is opportunity to capture a ton of replenishment power.

Catamaran with 3kW solar replenishing lithium batteries

The Secret is Rate of Replenishment Power

Charging at 10kW from the engine gives 5kWh every half hour. Running from two engines gives double that.

That means in one hour engine time, on both engines you have recovered 18-20kWh. Thats the same as you would get from solar in perfect weather all day!

So run the water maker, spa heater, all electric cooking and electric pizza oven. We have you covered.

In the spa on catamaran with plenty of energy

Maximum Power is 23kW from Two Units

Charging at 10kW from the engine gives 5kWh every half hour. Running from two engines gives double that.

That means in one hour engine time, on both engines you have recovered 18-20kWh. Thats the same as you would get from solar in perfect weather all day!

So run the water maker, spa heater, all electric cooking and electric pizza oven. We have you covered.

Hybrid Synchronous Alternator

This is no ordinary alternator. If you are familiar with EV's, their motors are synchronous with AC to DC inverter drives and run in regen mode.

This hybrid unit is based on a permanent magnet generator. However for precise control over a wide range of speeds, some field excitation is introduced.

In a brushed 48V alternator,  a direct current (DC) flows through field windings on the rotor, creating the necessary magnetic field. 

In this hybrid synchronous alternator, permanent magnets and electromagnetic field windings are combined to generate the magnetic field. The permanent magnets provide a constant baseline magnetic flux, while the field windings, located on the stator (and NOT the rotor), allow for dynamic adjustment of the magnetic field. This design often eliminates the need for brushes and the digital inverter control changes the excitation and power output very precisely.

Comparison of New HYBRID Technology with Alternator + Wakespeed.

 

Feature

Hybrid 48V 300A Peak Permanent Magnet Alternator with Scotty AI (HESA)

Traditional 48V 130A Alternator with Wakespeed 500 remote field control.

Winner

 

“Alternator” Type

Hybrid Excitation Synchronous Generator
 (permanent magnets + hairpin windings)

Field-excited rotor only

HESA

Rotor Design

16 permanent magnets
 + excitation windings

Field windings only

HESA

Power Density

1.65 kW/kg (advanced hairpin)

Lower due to round-wire winding

HESA

IP Level

Brushless Motor: IP25.

Waterproof Inverter: IP6K9K

Generally Brushed

IP23 or lower

HESA

Dual Stator Design

Dual three-phase, 30° shifted

Single three-phase

HESA

Ripple Current Reduction

Significant (30° phase shift)

Higher ripple

HESA

Noise Vibration Harshness Performance

Optimized (low ripple and torque smoothness)

Higher NVH

HESA

Efficiency

Higher (permanent magnets + hairpin winding)

Lower (field-excited losses)

HESA

Fault Tolerance

Dual stator allows operation in partial failure

Single stator, no redundancy

HESA

 

Peak Generator Power

12 kW

6.2 kW

HESA

Peak Efficiency

≥85%

60–70%

HESA

Power at Idle
 (engine ~600RPM)

3.0kW

300-500W Typically

HESA

Continuous Power Hot

≥5.5~7.0kW kW

5~7.0 kW

HESA

Maximum Speed

18,000 RPM

~8,000–10,000 RPM

HESA

Operating Temperature

-40°C to 105°C

-20°C to 80°C

HESA

Lifetime Expected

10 years, 300,000 km, 8,000 hrs

5–7 years, 150,000–200,000 km

HESA

 

12V and 48V Isolation

Negative side Earth isolated

Yes

No

HESA

Integration with Factory 12V or 24V Alternator

Full Integration for added power as solar backup at idle

None

HESA

Diagnostics and Protection

Of Load Dumps

Inverter/motor diagnostics,
100% load dump protection

Limited and depends on Battery

HESA

ISO 26262 ASIL B

Automotive Safety Standard

Compliant

Not compliant

HESA

Insulation Grade

Grade H (180°C)

Grade F (155°C)

HESA

Speed is Hybrid Alternator speed generally 2.8 times engine speed

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