A Hybrid Electric system offers a number of advantages for a Narrowboat some of these are detailed below.
The Hybrid Marine system provides an Electric propulsion system more than capable of propelling a full size narrow boat at 4mph with sufficient power for manoeuvring on canals and rivers. While operating on electric power the system is almost silent, with the only noise coming from the propeller wash and a small hum from the motor and belt drive.
On NB Chelonian (60ft trad narrowboat) the system is capable of propelling the boat at a comfortable cruising speed (3 - 3.5mph) with a battery drain of around 70A or 3.5Kw. With the 500Ah battery this will allow around 5 hours of electric propulsion from a full charge, and with a recharge rate of 100A this is more than enough for a days cruising using 50% electric and 50% diesel power.
Domestic Electrical systems on Narrowboats usually consist of 12v systems charged from an alternator on main engine. Mains power is usually obtained from an Inverter running from the 12v system. This solution is limited in both maximum power (1 - 2Kw @ 230v is typical) and the maximum amount of stored power available from a 12v battery system (typically 300-400Ah equivalent to 2.5-3.5Kwh). This type of system results in limitations on the sorts of electrical appliance that can be used, and generally ruling out electric cooking and washing machines. The limitation on stored power means that electrical power mush be carefully managed with unnecessary lights and appliances turned off when not in use, and demands that the batteries be fully recharged daily often resulting in long periods of engine running for battery charging while stationary. Using a 40Hp diesel to generate 1Kw of electrical power for battery charging is extremely inefficient and causes noise and smoke annoyance for the boat user and their neighbours.
To go some way to overcome these problems an engine mounted 230v generator system can be added allowing washing machines and or electric cooking to be used, but only while the engine is running.
A more expensive solution often used on live aboard boats is to add a separate silenced 230v generator system. This then makes electrical cooking and washing machines practical but adds significantly to cost and space requirements.
The Hybrid alternative
The Hybrid Marine Solution allows the LEM electric Motor to be used as a 5Kw generator producing 48v DC while the engine is running, this is approximately four times more power than is available from a conventional system. With suitable batteries this allows either much faster battery recharging, or more likely allows the use of much larger batteries. The 5kw output also means that using the engine to recharge batteries is much more efficient and recharge times are significantly reduced.
This addresses the limitations of both the charge time and the amount of stored power available on the boat, and coupled with suitable 48v Invertors allows plenty of 230v power to be available for electric cooking and washing machines.
NB Chelonian is being designed to have the Hybrid Marine system along with 500Ah of 48v batteries storing around 20Kwh of energy. This is coupled with two Victron Multiplus units offering 6Kw of continuous 230v power (peak 12Kw) which provides plenty of power for electric cooking and washing machines. The large amount of stored power means that the boat can provide domestic electrical power from the batteries for several days without the need to start the engine to recharge.