Case Study: Karma
Once powered by a 100hp diesel engine and an 8kW generator. Today, she’s the flagship of OSEA’s vision: a fully hybrid-electric yacht.
Her hybrid-electric conversion shows how legacy vessels can be reborn, combining classic design with modern technology.
The Conversion
At the heart of the system is a 60kWh 48VDC battery bank that powers all hotel loads and propulsion, supported by independent batteries for the bow thruster, electronics, and generator start.
Life
Aboard
All house loads are powered via batteries and renewables - without a whisper of diesel.
Charging is managed intelligently, with a 20kW generator, 1.1kW of solar, 400W wind, and 1kW regenerative propeller input, ensuring continuous operation and long battery life. The galley was modernized from propane to all-electric appliances, including induction cooking, convection oven, and highly efficient refrigeration.
Comfort and utility are supported by a 12,000 BTU air conditioner, efficient hot water, and robust plumbing systems.
The details
Full Specs: Systems That Power an Electric Voyage
Here is the full ship overhaul
- From a propane Force10 four burner cooktop with oven - to 2 large induction burner cooktop with 3000 watts.
- Convection AirFryer capable of a whole chicken with 3000 watts, and microwave with 1000 watts.
- Two freezers, ~8 cu.ft. capacity, one fridge ~6 cu.ft. capacity. Insulated to R60. Compressor for the freezers and fridge - ~400 Watts when needed.
- 24VDC LED Outdoor COB throughout the boat, about 120’ in the interior, 30’ in the cockpit, dimmable RGBW lights. The LEDs use ~9 watts per foot in full power.
- 24VDC Rechargeable spot reading lights and spot tube lights in critical areas, ~6 watts per hour of operation.
- 24VDC Automatic sensor lights in the heads, rated for 6 watts per hour.
- 24VDC Navigation Lights, 3 watts per hour in anchor light mode, 9 watts per hour in steaming mode. Deck lights 12 watts per hour for both the mizzen and main flood lights.
- Machinery room, 2 x 40 watt per hour bright white directional flood lights, 120VAC.
- Air Conditioning - Single 12000 btu AC unit, runs 120VAC, 1500 Watts at full power.
- Furuno Suite of electronics, 48nm Radar, depth, speed, wind, GPS, AIS. We also carry an Echosounder sonar. Two build in VHF radios, two handheld VHF radios, 9” screen.
- Orca Core and Display as alternative. IPAD backup.
- Total Power for the above maximum is about 200Watts per hour, with intermittent use.
- Adding a HAM radio in near future, but not yet. Power unknown at this point.
- Starlink that uses about 150 watts per hour when in use.
- Furuno Autopilot, estimated power about 200 watts when in use, supported by a Kobelt steering pump, uses about 240 watts when in use, backed up with a manual pump.
- 8 Gallon hot water heater, 1200 watt per hour capacity when in use.
- Headhunter freshwater pump, set at 300 watts per hour when in use.
- Raritan fresh/raw toilet, about 100 Watts when in use on freshwater, 140 watts when in raw water.
- Jabsco Electric head, about 100 watts when in use
- Groco built in Blackwater and grey water pumps, each will draw about 200 Watts per hour when in use.
- Rule 3500 GPH bilge pump, will draw up to 300 watts per hour when in use.