Getting the energy equation right is not only important, it’s also extremely satisfying to a wanna-be geek like me. At the end of the day we want to have enough electricity onboard to be a bit profligate with our power use. Leave the VHF radio on for inter-anchorage communications, run the SSB for the net morning and evening, charge phones, kindles, laptops, enjoy good lighting, have plenty of fresh cold and hot water, and use various small appliances in the galley. In addition, we may have our mast top WIFI extender and attached router energized, we generally leave our AIS transponder on so various friends might find us as they’re approaching an anchorage, and often we’ll leave the NMEA 2000 bus powered so we can monitor wind and depth under the boat as we swing about. We’ve been known to anchor in “kinda shallow” water and it does get breezy out here at times. Enquiring minds want to know!
If we’re underway more power-hungry devices come one, including the B&G Zeus3 12” chart plotter, radar, and electrically actuated hydraulic autopilot. Whether at anchor or underway the stereo might be playing. At anchor we’ve got the anchor light burning all night, if underway we’ll run the tri-color light at the top of the mast and various red lights inside the boat so we can see to move about and make a cup of tea.
The good news is that LED lighting has pretty much made lighting loads insignificant. While WIFI repeaters and phones don’t use a lot of power, all the communications and computing devices together do begin to add up to a bit of power use. Stereos use a bit of power, as do fans that keep us cooler in the galley or while sleeping. Radios use some power, a little in standby, a lot more when transmitting. The big whammy users are the AC powered hot water heater and the water maker, and the autopilot when underway but its power draw pales in comparison to the other two biggies. Autopilot power demands have a bit to do with the sailing conditions, as the harder the autopilot has to work to keep us on course, the more juice it uses. Keeping the sail plan balanced helps, but some points of sail and sea conditions as well as autopilot operational modes use more power than others.
All in all, it’s a bit difficult to predict what the real-world power use will be, so it’s a little hard to decide how much solar power and battery storage will be necessary to achieve a “carbon neutral” footprint. We do our best to reserve fossil fuel use to the dinghy outboard or the diesel propulsion. Our first guess at all this was in 2014 when we originally equipped JollyDogs with 800 amp hour of LiFeP04 cells and 920 watts of solar panels operated with a single solar controller. In the sunny Mexican climate that worked out pretty well, but our plans were to head for cloudier climes and a wider range of latitudes. During our 2018 refit we upgraded to 1440 watts solar, each hard panel with its own controller, and installed 720 amp hours of new LiFeP04 cells. We’ve now lived with this system for about 18 months and it seems to be working out pretty well. There have been a couple of extended rainy spells when I’ve dug out the Honda 2 kilowatt generator so we could run the water maker or the hot water heater, but otherwise the solar has gotten the job done. If we are motoring somewhere we always exploit the alternator output to top up the fresh water and the port engine also heats the water.
Here in the anchorage most boats run a generator several hours a day, especially the monohulls as they really don’t have the real estate for lots of solar. Being freed from the tyranny of using fossil fuel for power generation is a wonderful thing and it’s great being a quiet boat.
If we could only do something about the light pollution out here! Anchor lights aren’t too bad and often there’s no manmade lights on shore, but that darn moon! I really want to enjoy the Perseid meteor shower this week, but Mr. Moon ain’t helping!
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