Moving Aboard – Part 3

Things were starting to settle down a little bit aboard Copperfield. I had limited quantities of heat, light, and water available while I was working, and the weather was starting to get warmer. It was time to start thinking about the electrical systems. Up to this point, I’d deliberately done as little as possible to the electrical wiring because I didn’t know exactly what I was dealing with. It had been too cold and wet to go digging around in the bilge of the boat to trace wires, but as the weather warmed up, I could get stuck into mapping out the electrical system and figuring out what I needed to change.

To begin with, I didn’t even know where the electrical fuse box was. I knew that there had to be one, but I’d never actually seen it. The internal wiring was all run beneath wooden cladding, and disappeared through the rear bulkhead. When I replaced the back deck with temporary plywood, I’d noted that the isolator switches were mounted in the bilge near the cabin door. There was no fuse box there, but a more thorough search in the spring sun revealed a small automotive fuse box on the opposite side of the boat, near to the engine electronics. Surely this couldn’t be the fuse box for the whole boat?

There was no fuse box there, but a more thorough search in the spring sun revealed a small automotive fuse box on the opposite side of the boat, near to the engine electronics. Surely this couldn’t be the fuse box for the whole boat?

Copperfield, undercoated with a solar panel fitted

The engine electrical system was in very good condition and aside from the battery fault, everything looked to be in working order. I decided that it was time to split the electrical systems again, replacing the single battery with a bank of three batteries for the internal electrical system, and a single dedicated starter battery for the engine. Part of the beauty of moving aboard was cutting the cables that bound me to the grid. I didn’t want to rely on the engine to charge up the internal batteries, and I knew that I didn’t want to rely on shore power to run the boat. Solar power looked like the most sensible option. Wind generators were a second choice as I was worried about the amount of noise that they would make when attached to the roof. I did some rough calculations and reasoned that I would need about 10 amps per day for lighting, phone charging, water pumps, and a small TV/Radio. On top of this, I would need to consider things like a cooler for perishable goods and mains electrical equipment. I wasn’t too worried about 240v electrical power, because I didn’t really own any electronic goods that required AC power. At most, I would need to run a microwave and a vacuum cleaner – neither of which would be run for more than a few minutes at a time. All of these things were running through my mind as I came up with the final list of ‘big’ parts I would need to power the boat:

1 x 240w 36v solar panel

Usually, when people wire a boat or an RV for solar power, they choose a 17v solar panel, because i it can be used with a very inexpensive charge circuit. A 36 volt panel is much cheaper than a 17 volt panel, but requires a more expensive charging circuit. The advantages to this type of panel is that it’s a single low cost item that is easy to replace, has a 10 year warranty, and the higher voltage means that there is less power loss in the cable when running over several meters. At maximum power this panel gives 240 watts, which is 20 amps at 12v.

1 x 20A MPPT (Maximum Power Point Tracking) solar charge regulator

These regulators are much more expensive than a standard solar charger, but are more efficient and can handle a wide range of input voltages. They use a technique called switch mode regulation, which controls the charge by turning on and off very rapidly, rather than dumping excess power as heat. The model I chose also had an external LCD display for battery monitoring.

1 x 2000 watt full sine wave 12v-240v Inverter

I used a full sine wave inverter because I knew that I would be using a microwave on board. A cheaper square wave inverter would have been fine for most uses, but certain electrical devices like microwave emitters and synchronous motors (like the ones used in microwave turntables) don’t work properly without a smooth sine wave. I figured that 2 kilowatts would be plenty of power for anything I needed to run, but chose an inverter that could handle 4 kilowatts maximum for short periods.

3 x 110Ah deep cycle batteries

Lead acid batteries might be old fashioned, but they are still in use for a good reason. They’re cheap, and require minimal maintenance. I chose three batteries so that I would have a good reserve of power if the weather was bad or I needed to use the inverter for an extended period.

1 x 700w microwave

Just because I’m living aboard doesn’t mean that I shouldn’t have the conveniences of living in a house. With solar power, a microwave actually makes a lot of sense. Firstly, the solar power you harvest is essentially free power. Cooking something in the microwave doesn’t cost you anything if you have the power to spare. Gas and solid fuel need to be replaced when they run out. Sacks of coal and propane bottles are heavy to carry, and take up space. Secondly, if you’re reheating something, then the microwave produces much less steam than most other methods of cooking and that means less condensation inside the boat.

1 x Individually switched marine fusebox

I didn’t like the automotive fusebox that was fitted into Copperfield, and I’d owned one of these fuseboxes on my previous boat. I like being able to see when power is switched on to certain devices, particularly when I’m still messing around with the internal wiring.

Bare wires coming into cabin from bilge after rewiring.

With the essentials ordered, I carried on inspecting the wiring and decided that I would need to make a couple of big changes. The wiring to the internal circuits was quite thin, and entered the boat on the starboard side of the bulkhead. The fusebox was on the port side of the bulkhead, and the batteries were on the starboard side. The wiring had to travel to these points around the back of the stairwell in the rear deck. That meant that there was roughly 15-20 foot of cable running between the battery and the fusebox before it even got inside the boat. I also discovered that the automatic bilge pump wasn’t pumping the water out of the boat. The bilge pump is designed to stop the boat from filling up with water, and consists of a medium sized impeller pump with a float switch connected to it. When the water level rises above a certain point, the float switch activates the pump and the water is pumped out of an outlet in the side of the hull. The wires connecting to the pump were so thin that the pump couldn’t draw enough power to get the water out. As a result, the float switch wouldn’t turn off and the batteries would eventually go flat. Luckily, the wire had come loose and the pump didn’t activate at all. An afternoon spent with some thicker cable, some wire cutters, a bag of crimp connectors, and a tube of silicone rubber solved all of these problems. The excess cable was chopped out and replaced with a short run of 270 amp battery cable (I used such heavy cabling because I knew that I would be fitting an inverter) and a 300 amp isolator switch. The isolator switch cuts all electrical contact between the battery and the internal electrical system, so if anything bad happens it’s easy to stop the power at its source. It’s important that it’s accessible and clearly marked. I reused some of the internal wooden cladding to make a power panel, and mounted it near the door.

Electrical panel and solar charger in place.

Connecting the batteries in the bilge was surprisingly hard work. Each battery is fitted into a box, which sits on a shelf made from an offcut fibreglass catwalk. The batteries need to be strapped onto the shelf, and the battery cables (which are heavy duty) need to be looped between the contacts. Fitting the connecting lugs onto the cables required a blow lamp, an engineering vice, and lots of solder. First, the metal lug is crushed onto the trimmed copper wire, and then solder is melted into the gap to make a good connection. It sounds easy enough, but it requires a bit of force to crush the metal and just enough heat to flow the solder without melting the cable sheath.

With the batteries connected, I could attach the controller for the solar panel inside the boat, mount the solar panel on the roof, and run some 6mm2 cable between the panel and the charger. Fixing the panel to the roof was quite awkward, because the roof of the narrowboat isn’t flat, and there are all sorts of obstacles in the way. I would have liked to mount the panel near to the back deck, but the position of the roof vents and chimney made it too difficult. Instead, I mounted the panel in an area of open roof near to the bow and ran the extra-long length of cable to the charger mounted near the back door. I wanted to enclose the sides of the panel in a neat wooden box, but as a temporary measure I screwed the panel in place using a very simple aluminium tube frame and some wooden blocks. I drilled through the roof and fitted a waterproof gasket for the cable. There was just enough room in the existing cable trunk to pull the solar panel wires along the length of the boat. When I connected everything up, the system registered 36v coming from the panel, and started charging the batteries with no problems.

Connecting the inverter was very easy. I just connected the heavy wires to the rear of the inverter, and flicked the power switch. The LED display on the inverter told me that I had good input and output voltages, and I was ready to plug an appliance in. Fuses were built into the inverter itself, and a simple test with the vacuum cleaner told me that I had 240v power. For the sake of convenience, I ran a length of flex in a cable trunk beneath each gunwhale, and connected a couple of standard electrical sockets to each side of the boat. On the left side, I would be able to plug in the microwave and vacuum cleaner. On the right, I mounted it above the kitchen worksurface so that could plug in any other kitchen appliances. The power cables exited the trunking near to the door and plugged into the inverter using standard mains plugs.

LED lighting, brighter and lower power than the original incandescent bulbs.

I removed all of the internal lights, and replaced the incandescent bulbs with warm-white LEDs. The LEDs use a fraction of the power of an incandescent bulb, and last much longer. If I had brought the LED bulbs ready assembled and fitted them into the existing light fittings, then they would have cost a fortune to replace. Instead, I returned to the old friend eBay and found some LED units that cost less than £1. They needed to be soldered into the lights, but I’d rather spend a couple of hours with the soldering iron than spend nearly 10x that much cash on a ready made solution. I also brought a roll of self adhesive LED strip lights, that could be cut to length and stuck in place under the gunwhale to give some warm light. I must admit that the LED strips are much more effective than I thought they would be, and were incredibly easy to fit into place. I already had a cable run into roughly the right area, so I just needed a switch box to control them. I used an old sardine tin as a project box, which looks just fine screwed in place.

It was about this time that I decided to move the boat nearer to my home. The summer was getting near, and the days were getting longer. I could cut the commute to the boat from several hours to a few minutes. It was easier to start working on bigger projects with more tools. Now that I had 240v power, I could use power tools anywhere I moored and the sunlight would give me all of the free energy I needed to get on with the project. I would revisit the electrical wiring again in the future, but for now I could move on to solving other problems.


The power cupboard is on the left of the photo, with the inverter behind the (easily removable) wooden cladding.


1 Comment

  1. Hi,

    1. when did you get the boat?
    2. How efficient are inverters compared with rotary alternatives?


    PS, does the boat come under gardening, shed or kitchen categories? 😉

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