Answers to Frequently Asked Questions

Electrically powered narrowboats and barges

Solar powered electric propulsion is a practical, economic alternative to diesel engines on narrowboats and light canal barges. Solar panels can provide power for over 1000 miles cruising per year for many decades.
  • Low maintenance and low running cost.
  • Space-saving installation.
  • It's quiet and clean.
  • 25% discount on boat licenses from BW and EA.
  • Power for comfortable accommodation.
  • Lower carbon footprint and low emission.

Maintenance

Typical maintenance schedule is easier than for a diesel engine: Wipe clean solar panels weekly, top up batteries monthly, change motor brushes every 2000 hours cruising, new batteries every 3000 discharges or 7-10 years.
Motor installation

With equipment and instructions from The Solar Boat Company, equipping a narrowboat or barge with electric propulsion or solar power is as easy as installing a diesel engine. Keep the narrowboat as light as possible, shallow draft with long curves at stern and bow. Not too much ballast is required because of the weight of the battery. The prop shaft thrust bearing and the motor can be mounted on steel cross member welded to the hull. The boat can have normal Morse lever type controls or compact controls can be mounted on the tiller handle or dashboard.
Performance

The slower you go, the further you can get on the stored power. Lynch-type Electric motors and the motor-control system have excellent efficiency over the entire speed range (about 90%). Just 2 horse power propels a narrowboat at about 3mph. A solar narrowboat with one kiloWatt of Solar panels would generate about 500kWh/y [Southern England, horizontal installation] which is enough for 1000miles cruising at 2.5mph.
Speed Power Solar miles with
1kW of solar
Range on 70% discharge
of 1000Ah/48V battery
2mph 750 W 55 miles 100 miles
3mph 2 kW 32 miles 56 miles
4mph 5 kW 17 miles 30 miles

The table shows the performance from an electric narrowboat.
900 Watts of solar panels produces 20kWh week, (average charge April-September).
Running the washing machine might cost a couple of miles cruising. Use of lights, pumps & radio only reduces the range by a few hundred yards per day.


Wider barges

Wide beam barges 10'-13' make great solar powered homes. However more than twice the power is required to cruise at the same speed as a narrowboat. Extra solar panels should be fitted, and a larger battery with a more powerfel charger. Modern broad beam barges tend to be a bit blunt ended, encourage your boat builder to lengthen the swim and bow curves and keep the hull light with V bottom or angled chimes, rather than the typical box-shape section.
Batteries

Wet lead-acid traction batteries are currently the most robust and best value. They need to be topped up with water occasionally or an automatic filling system can be installed. Our narrowboat installations typically use about 1 Ton [900AH at 48Volts]. With battery price increasing and solar panels becoming more affordable we now recomend fewer batteries and more solar power than in the past.
Lighter lithium
batteries are becoming better value and are a quarter of the weight for the same energy storage. They are ideal for smaller, faster, lighter electric boats.
Additional battery charging options

British Waterways and The Environment Agency are installing shore power points on their waterways. The River Thames has charging points every 15 miles, some marinas, waterside pubs or floating solar power-stations also offer charging for electric boats.
Generators

LPG, propane or diesel powered generators are often carried on electric narrowboats and might be required for long journeys or winter cruising. A water cooled generator can be plumbed in to heat a hot water cylinder. Between 3kW and 6kW is enough to give good extended cruising speed for a narrowboat.