Engine Running and Power Generation Costs

My diesel use and consumption varied widely over this five year period. For the first three years, my poor boat did little more than chug regularly from my mooring to either the engineering or fitters’ workshop to have what felt like an endless number of repairs, modifications and improvements made.

During this period, I used my diesel for engine propulsion only. During the last two years when I was living out on the cut most of the time, over the winter months when my solar array produced very little power, I ran my engine between an hour and an hour and a half every day to help charge my battery bank.

In 2016, I also used my diesel to run my Webasto central heating system MORE HERE

I cruised continuously from April 2015 and throughout 2016.. The longest I’ve stayed in one spot was two days before cruising

Five year diesel costs

for two or more hours the following day. I didn’t needed to conserve my power because the engine’s been running and therefore charging my batteries while I’ve been on the move.

I had four 160ah AGM batteries in my domestic bank. I replaced my old 135ah lead acid batteries in January 2016 with the larger capacity AGMs because the new batteries should last three times as long as lead acid batteries but only cost twice as much, and because they are maintenance free.

Boat battery banks aren’t always fitted in the easiest of places to reach in an often cramped engine room. Unscrewing the tops and then peering in aided by a torch to check if they need topping up is often difficult to do, so the likelihood is that this task will not be done regularly or even at all, thereby drastically reducing the battery bank’s life.

My fit and forget batteries removed yet another tedious maintenance task.

One of the most useful improvements I made to my boat is to have a Smartgauge battery monitor installed. It was fitted in the bulkhead between my bedroom and the engine room facing into the bedroom. At the touch of a button I could see the battery bank’s capacity whenever I wanted. I usually checked two or three times a day.

I have to admit to being a little wasteful with my on board power. I didn’t really needed to conserve it in the marina because I was always plugged in to the national grid. And then, with the amount of cruising and therefore engine running and battery charging I did in 2015 & 2016, I had a virtually unlimited supply. I also had a 300w solar array helping to keep my battery bank charged in the summer months.

Each day I used roughly 10% of my battery bank’s capacity. I needed to run my engine for two hours to top the bank up to 100% again. I did this during the course of my daily cruising during the summer. In the winter, the little electricity generated by then solar array was supplemented by running the engine.

My engine used 1.35 litres of diesel per hour. In 2016 when I bought my fuel at Calcutt Boats at113p for propulsion and 65p for heating, and if I declared it at at the default split of 60/40 (sixty per cent propulsion/forty per cent heating), a litre of diesel cost me 93.8p or £1.27 per engine running hour. My batteries therefore cost roughly £2.50 per day to charge.

I don’t know the difference between fuel consumption when at rest for battery charging or when actually cruising, but I don’t think it’s much at all. I came to the conclusion that if I had to run my engine on average for two hours each day anyway I might as well use it to cruise and enjoy the variety the inland waterways network has to offer.

Paul Smith

After six and a half years living on a narrowboat on England's inland waterways, Paul and his wife Cynthia wandered Europe by motorhome during the winter, and on the Dutch and French waterways in the warmer months on their 35' Dutch motor cruiser. However, the pull of England's muddy ditches proved too much for them. Now they're back where they belong, constantly stuck in mud in a beautiful traditional narrowboat.