Electrics – Living on Wind and Sun

Since Luckyfish was launched in 2012, she has never been connected to the grid. There is no need for a shore-power socket and no petrol or diesel generator aboard. The boat is powered fully by the sun, the wind and soon to be, water too. Living this way is one of the biggest kick’s I get out of cruising. It is almost as rewarding as sailing itself.

Energy storage comprises 3 x 105Ah AGM batteries in the port hull and 2 x 105Ah AGM’s in the starboard hull, totaling 525Ah. Both battery banks are isolated. A sixth battery is located at the forward end of the port engine housing. It is isolated from the rest of the system and starts the two Yamaha 9.9HP outboards and powers the windlass.

Solar charge is fed first through a normal battery isolation switch, re-purposed to send the charge to both battery banks, or just the port or starboard one. Solar controllers are installed on both battery banks and on the engine start battery which is tied into the port side charging lead.

Prior to the Atlantic crossing, I added a 12V EchoTec watermaker, Broadband 4G radar, 12″ chart plotter and AIS transponder to her existing load, which consisted mainly of refrigerator, basic nav instruments and lights. It was pretty obvious that we would have an energy deficit, however, with good management of demands, we sailed across the Atlantic utilising all these items of equipment to the extent we needed, with just 270W of installed solar capacity.

So, just what does ‘good management’ translate to? Firstly, we prioritise our energy needs. For example, during the daytime in full sun with both banks topped off (normally by noon to 2pm) and everyone wanting a shower, I run the water maker for 30 minutes and produce about 30 litres of fresh water. This takes the port battery bank down to 50 or 60% or so and leaves enough time to restore the charge with the remaining hours of sunlight.

At night time, running the radar becomes the priority, as well as the chartplotter, AIS and nav lights, in that order. I regard the biggest risk we face at sea is colliding with another ship, although it is extremely unlikely. So our objective each day is to finish the daylight hours with a fully charged starboard battery bank, which runs the nav instruments including the radar. Without a hydro and/or wind generator we can not run the chartplotter and radar for long, so we turn it on every 20 or 30 minutes and scanned the horizon at various ranges before shutting down again. Standby mode uses just as much power so we have to shut it down. With the 4G technology, the power (and time) required to start-up the unit is minimal, compared to the old magnetron technology. It has proved to be an awesome unit.

None of this is ideal. We would like to be able to produce more freshwater, particularly the girls whose regular hair washes seem to gobble amounts that would make most salty cruisers cry, and, on passage, we would like to run the radar all night, especially with a range alarm, or two, set. At times the 12V fridge needs to be turned off at night when the starboard side nav bank don’t get a full charge.

To improve this in the 2017 season, I will be increasing and diversifying the power generation capability with a 300W hydrogenerator and a 350W wind generator. The purpose of the hydrogenerator is primarily to maintain charge at night time on passages to allow continuous use of the radar and chartplotter. The wind generator’s primary purpose is to provide charge on cloudy days at anchor, although it will contribute some charge on passages as well.

This should result in a robust system that provides oodles of power >95% of the time. All without the need for fossil fuels or marina’s.