Fitting solar panels

Running a diesel engine or portable generator to charge your batteries is a hassle. Not only that, but it disturbs the peace of a quiet mooring, and isn’t a very environmentally responsible way of obtaining energy.

Running your boats diesel engine isn’t very good for your boats engine: Most alternators only give a light load to a big propulsion engine which is designed to be run under much heavier loads. That’s why many people leave boats in gear while charging; but that of course, burns more diesel, and is even less environmentally friendly!

An alternative is to charge your batteries using clean, free, renewable energy which is Solar power. Although you need to make a reasonable investment to fit solar panels, you should find that in the long term you will even save money. You will save considerably on fuel costs, engine wear and tear, and battery replacement.

Solar panels can contribute significantly to your electricity needs of a narrowboat. There are several different types of solar panel on the market. Both traditional crystalline types, and the more modern amorphous types, work well on narrowboats.

Adhesive backed panels or panels that can be stuck with a silicon type glue are now the most appropriate solution for a narrowboat, because they can be stuck down with adhesive to the curve of the roof. They can even be walked on with soft soled shoes. 

In the summer, just one 68 Watt panel should supply all the electricity you need for lighting and water pumps. If you use energy efficient lighting where possible, such as LED or low powered fluorescent units to give the maximum light for the minimum power, you will in effect getting lighting for free. If you run a fridge and or a freezer you should consider fitting two panels of a higher wattage, since fridges and freezers are rather power-hungry compared to other on board appliances.

If you leave your boat for long periods of time and just want a solar panel to keep your batteries in good condition while you are away, you can get away with a smaller panel.  These small panels typically come in 5, 10 and 20 Watt sizes, are semi-flexible, and will gently bend to fit the curve of most narrowboat roofs provided the curve is not too tight. They can be mounted either using the 4 grommet holes in the panel corners, or by gluing the panels down.

Need more power? Then why not fit say two 130 watt units these will give you a total of 260 watt which should cope with even a fridge and say a freezer in high summer. 

What do you need to control your solar panels? 

The best device for a narrow boat is a MPPT controller. These can be bought for systems up to a 40 amp input to your batteries. The one we elected for was a 20A Tracer 2215-BN, this allows for up to 20 amp with an input maximum of 260 watt. This unit has a RS485 data connection which then allows you to connect a remote controller with LCD screen. This then tells you what is going into your batteries or whether the batter bank is full.The one we have fitted is a MT50 in black. It can be obtained in white. You can see a video of this unit here.

How do you wire up your solar panels? 

This is done by taking the outputs from panels and feeding them down the boat with a cable able to take at least 20 amps of power. This is then put into the input side of the MPPT controller. Then from the output side of the MPPT controller out to the end connections of the positive and negative of your domestic bank. This will then charge just your domestic bank. You can be clever and allow switching to either the starter bank, or the domestic bank. You will of course need fuses to be added to protect the system.

How much does it cost?

This depends on what you elect for. We had ours professionally fitted, with the following specifications.
Two 130 watt stick on solar panels in black.
All cabling and trunking.
MPPT 20 amp unit discussed above.
MT50 controller
Total cost £1200

The company we had ours system fitted by was “Run by the Sun” of Leicester. We found this firm very good and very honest.