||Electric Propulsion
Electric Propulsion 2017-10-24T10:13:18+00:00

ELECTRIC PROPULSION

Looking for a greener and quieter option for your narrowboat? Electric powered narrow boats are becoming more widely available on the waterways.

Electric Propulsion… An Introduction

Electric narrowboat motors are becoming common place, they are safe, green, reliable and wonderfully quiet. The image of electric cars today is now faraway from the once ubiquitous milk float.

The benefits are huge. Electric motors need a lot of infrastructure but when not travelling this can be used on other narrow boat appliances. It makes life on-board a lot more comfortable and convenient.

It is not always possible to charge a narrow boat overnight using shore power a hybrid system is required. Put simply, hybrid power is the combination of different technologies to produce power. This may mean there is an electric motor working in combination with a petrol or diesel motor that in turn runs a generator.

There are 2 systems detailed below. Within these systems there are choices to make such as the size of generator and battery bank. Choice can be confusing but please don’t be put off – it’s really just a question of imagining your life on board and how you would use your narrowboat.

A serial hybrid electric propulsion system for a narrowboat

Serial Hybrid

In the serial system, a battery bank powers a large electric motor that turns the propeller through a direct shaft. The battery bank itself is charged by either the generator, shore power or solar panels. It is a very simple system and can be tailored to suit individual needs very easily. For instance, if you are planning long journeys it would suit to have a large generator. On the other hand if the boat was only going to be used at weekends, charging using the solar panels with a small generator backup would offer a low cost and more environmentally friendly option.

Parallel hybrid electric propulsion system for a narrowboat

Parallel Hybrid

A parallel hybrid option uses a conventional diesel motor to turn the propeller via a direct shaft. An electric motor which doubles as a generator is connected in parallel to the prop shaft. When cruising at low speeds, excess power from the diesel motor is picked up by the electric motor which, acting as a generator, tops up the battery bank. Turn the diesel motor off and the electric motor can be used to drive the prop shaft. Narrow boat batteries can also be charged via solar panels or shore power.

This system is slightly more complicated than the serial system and requires more maintenance however it suits narrowboat owners that require a lot of power, for instance, those operating in tidal rivers for long periods of time.

Electric Propulsion… Understanding How Much Electricity You Need?

If you have a narrowboat with an electric motor you will also have a large battery bank, solar panels and diesel generator. Having access to a large amount of energy means that there is an opportunity to use a wide range of appliances that bring comfort and convenience to your time on board. Helping with on-board safety and convenience, it means that you don’t need to use gas for cooking and heating.

Below are some scenarios that demonstrate power consumption over 24hrs. It assumes that all cooking, hot water, heating and propulsion are electric. Please note that miscellaneous is a combination of lights, computer, TV, heated towel rail and hair dryer.

These graphs are a worse case scenario considering that they don’t take into account the 4kW diesel heater that is more than capable of heating the whole narrow boat.

Electricity Examples… Summer (Normal Use) Total Power Consumption = 30.3 kWh

Narrow boat electricity usage during summer months
Summer electricty usage on a narrowboat

Electricity Examples… Summer (Heavy Use) Total Power Consumption = 49.5 kWh

Heavy electricity use on a narrow boat in the summer
Average energy use in the summer on a narrowboat (heavy use)

Electricity Examples… Winter – Total Power Consumption = 50.2 kWh

Winter electricity use on a narrowboat
Electricty used on a narrowboat in the winter

Electric Propulsion… Conclusion

It can be seen from these graphs that consumption varies dramatically depending on the use of the narrow boat. It is possible to replenish batteries by solar power only but this may take a few days. This could suit weekend users but wouldn’t suit those who like to cruise continuously. A small 4kVA generator would work in all the situations above however it would need to run for long periods of time. Better to have a larger generator that can replenish the batteries quickly.

Silence is golden as someone once said. For those who are going to travel very long distances the parallel system might suit best of all.

Electric motors have brought a world of choice to our canals, it is important not to be afraid of this choice and understand that these systems are proven and very reliable requiring only minimal maintenance. But best of all they offer the greenest solution out there today.

Electric Propulsion

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