Believe it or not, long-distance cruising by sailboat requires electrical energy. At least on our boat it does. By today’s standards, we have most of the electronic systems that you could find on a cruising sailboat, including radar, chartplotter, GPS, AIS, autopilot, wind/depth/speed instruments and VHF radio. We also have a few extra goodies such as our SSB, stereo, laptop computer, refrigerator and water pressure system. Add in the bilge pumps, lighting and a few other odds and ends, and we have a fairly high demand for 12VDC electricity; between 90 and 100Ah/day.

As far as battery capacity is concerned, we like to spend as much time as possible anchored and away from marinas, which means we don’t get to ‘plug in’ for days at a time. To make this possible, we upgraded the factory DC system to give us more capacity and greater charging capability while running our engine. The downside is added weight, but we feel this compromise is OK. On our first voyage to the Bahamas, we carried a Honda EU2000 generator in our starboard locker. These generators are quite popular with cruisers in the south and we found ours to be a valuable asset. It is easy to use and generates enough AC power to charge our house bank back up in less than 2 hours. The generator was fairly quiet, but we tried to avoid using it in crowded anchorages. However, I was less reluctant to use it when neighbouring boats had their own gensets and wind generators whirring away.

Over the past year or so, Mary and I researched alternative energy sources for Strathspey including wind generators and solar panels. There are obvious advantages to both wind and solar, but in the end, we chose solar because it is quiet and we have a convenient location to mount the PV panels. So, in April 2012, we had two solar panels mounted over our bimini and I wired them up to our DC system. We installed two Solarland 85Watt panels which feed through a Solar Boost 152iX MPPT charge controller (Blue Sky Energy) to our DC positive bus. Over the summer, we learned that the panels provide enough power to handle our DC energy needs, even on cloudy days. Sticking our necks way out, we sold our Honda EU2000 generator. In the end, we reduced our dependency on gasoline and reduced the on-board weight by about 30lbs

Our summer experience in lake Ontario didn’t hold up in the south, where the days are shorter and the refrigerator runs a lot more steadily. So, before our next trip, we’re adding two more solar panels and putting that 30lb generator back in the starboard locker.

A drawing of our 12DC system is in this schematic Here are the details:

  • The house battery bank consists of four 6-volt Lifeline AGM batteries (Type 4C). Total battery capacity is 440Ah, which is enough to keep us going for a couple of days at anchor. I estimate out peak enegry consumption to be about 1000Ah per day. Originally, Strathspey was delivered with two house batteries and an engine starter battery strapped to a battery bed behind the saildrive, under the aft bunk. It’s a tight fit, and not much ventilation. After measuring, I discovered that the four 6-volt batteries would occupy almost exactly the same space, so I displaced the starter battery (a problem to be solved later), built a new battery bed and dropped in the new batteries.
  • The engine starter battery is another Lifeline, but designed for cranking. It’s a model T3100 and I had to get it on special order from Polytek in Montreal. I found a space for it under the aft bunk, behind the holding tank. A perfect spot, but requiring slightly longer cables.
  • We’re on our third alternator – a 125A Hamilton Ferris. I believe, at the time, it was the largest alternator you can get to work with a single 1/2″ belt. This brute replaces a 75A Balmar (model 912) that worked like a charm, but was under-sized for the new house bank. The Balmar replaced the OEM Yanmar 55A alternator that came with the boat. When I installed the Balmar alternator, I also installed a Balmar MC-612 digital regulator. This system could be programmed for AGM batteries and we didn’t experience any problems with either the AGMs or the charging system. The MC-612 works with the new Hamilton Ferris as well.
  • I did a lot of re-wiring on Strathspey, as you might see in the schematics. The objective was to have two separate battery banks that could be combined for charging and emergency starting. All charging sources (solar, shore ppower and alternator) feed the house bank, which passes current to the engine bank through a Blue Sea Systems battery combiner. Temperature sensors on the house bank and the alternator case protect the system from overheating.
  • Strathspey has a Magnum 2012 charger/inverter, which provides 100DCA charging capacity and 2000 Watts of AC for whatever you can use it for. We have a few small appliances that require AC. We also have a Magnum batter monitor, replacing the Link 2000, and which allows us to monitor energy consumption more closely.
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