Electric Engine Options

We wanted “Old Nick” to be an electric narrow boat, but as with all things in life, there were a number of different “flavours “of electric engine designs and we had to decide which one would be best for us.

The simplest is the “All Electric” design, where you have a single electric engine, a big bank of batteries and a means of charging them.

One Electric Engine

This design works well for vessels that are doing short trips and always returning to base at the end of the day, where they can plug in to the shore supply, ready for the next day’s cruising. A lot of “Day Boats” operated by hire companies are moving to this type of design and Ortomarine have already built two large “All Electric” Trip Boats.

For vessels that are cruising for longer periods, over greater distances, such as private holiday boats and continuous cruisers, a different design is required. One of the first commercially successful designs, was the parallel electric hybrid, of which there are now many installations on UK canals and Ortomarine have already built six of these designs.

In parallel hybrid systems, you have two engines; one diesel and one electric, which are linked via a special transmission system. Both engines can drive the prop shaft, with the electric engine being used most of the time, but when the batteries get low or some extra horsepower is needed, for instance on a river section, the diesel can take over or in some systems both engines can work together for maximum power.

Diesel and Electric engines linked in parallel

With recent improvements in battery technology and electric engine design, a new, third flavour is now starting to appear on UK narrowboats, and that is the Serial Electric Hybrid.

In a serial hybrid, there is a single electric engine driving the prop shaft, but if the batteries start to get low, a small, quiet and efficient diesel generator can be started that will charge the batteries whilst still underway. With a good solar setup (1200W or more), the need to run the generator in summer months is rare and in the autumn/winter, a night or two on a visitor mooring in a marina, on shore power, will soon top up the batteries.

One Electric Engine driving the prop, with generator backup

Taking all of the above in to consideration we decided to go for the latest Serial Hybrid solution, for “Old Nick”. The main reasons being;

  • Quieter and more practical generator charging
  • When diesel is used for charging, more efficient, fixed RPM generator
  • Wider choice of electric engine manufacturers
  • Latest technology

Currently, it is not possible to completely eliminate the use of diesel on a “continuously cruising” narrowboat, but in conjunction with the other changes we are making, we should significantly reduce our diesel consumption and environmental impact, of this boat.

Looking around, there are not that many Serial Hybrid Narrowboats, but hopefully our adventures with “Old Nick” will inspire more people to look closely at this new and exciting technology.

9 Replies to “Electric Engine Options”

  1. You’ve certainly weighed up the options and appear to have chosen well. Enjoy all your planning for “Old Nick” cos you’ll soon be onboard xx

  2. I’ll follow with interest as a serial electric set up is my choice too. Looking forward to hearing about your choice of batteries, ‘silent’ generator setup, and how you’ll combine the various charging options. There are also side issues such as how will you heat your domestic water?

    1. Hi Rona,
      We will be covering all of the issues you mention over the coming weeks, and feel free to ask any questions and I will do my best to answer them.
      All the best

  3. Hi Paul .. Thanks for info on your preferred propulsion system .
    Just a few questions.
    Is the electric motor directly coupled to the prop.shatft.
    or do you have reduction gearbox, or clutch, between motor and prop?
    can you reverse the motor?
    Do you have a standard prop or controlled pitch prop ?
    What will be maximum prop RPM?
    Is the arrangement computer controlled ? do you have manual control of the elements?
    Glad that you went for the “Green ” option
    Best Wishes
    Uncle D

    1. Hi Derek,
      It is a direct coupling, with no gearbox and the electric engine controller can make it spin in forward or reverse.
      Choice of prop is always a critical factor and we will be going for a conventional prop, which I will be covering in a future post, as the prop we are going to use might surprise some people.
      The engine will be computer controlled with no manual control, and the throttle lever communicates with the engine controller via a CAN interface, as used in all modern cars, so pretty well proven and tested.
      I don’t want to go in to too much on the engine just yet, as it is a brand new model and I will be doing a big post on this in a few weeks.

  4. Interestingly nb Ampere removed his solar panels. Personally it concerned me that his Fischer Panda cocooned generator in the bow was canal water cooled (no skin tank). All in all an excellent pioneer though.

    Following with interest, good luck.

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