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Do we need a generator, solar panels, wind generator, monster alternator, or large battery banks? Most of these questions were easy to answer for us. The Jule III is a narrow double ender that has precious little room for extras. For instance, conventional batteries have footprints incompatible with the spaces available. The only standard battery that fits are deep cycle truck batteries for a total of 150 amp hours (Ah) of capacity. We do not have room (or a desire) for a ‘gen-set’ to operate large 120 volt AC (vac) appliances.
We do have a small Four Winds III wind generator that produces some energy when there is a breeze in the anchorage (0-100 Ah per day (Ah/d) [ average 40 Ah/d]. In 2003, we added three shade tolerant solar panels that produce 24-40 Ah/d on an average day. In 2004 we finally bit the bullet and upgraded our battery capacity. This decision was driven in large part due to the diminishing availability of the TF-17 bateries that we used. We rebuilt the baterry compartment so that we could carry four group 27 batteries which increased our Ah capacity 300 %. Yet, we are able to cruise for months at a time without a shore ‘plugin’ or using the auxiliary engine to refresh the batteries. Our methodology is simple: balance our electrical needs with our available capacity. Here are a several examples: ENERGY REPLENISHMENT Jule III has three charging sources: the auxiliary engine, the wind generator, and the solar panels. Our engine has an 80 Ah alternator that charges the battery while motoring. The Fourwinds III generates at least 40 Ah/day when sailing and at anchorage when the winds exceed 10 knots (apparent). The solar panels (a 60 watt (W) shade tolerant panel on the dodger and two 40 W swingable panels on both the starboard and port beams) can generate a total of 6 amps (A) for 6 to 8 hours (i..e., 36 to 48 Ah/d) with full sun exposure. We cut these estimates by 50 % to address the inefficiencies in battery charging. In the ideal anchorage, we can add a minimum/average of 40/100 Ah to our battery banks per day. ENERGY CONSUMPTION Our largest non-discretionary consumer is the refrigeration unit. Though it is small and efficient, it still consumes 18-36 Ah/d. Not a whole lot left after that! Below is our typical daily energy budget while anchored (or sailing without benefit of the engine): The lower numbers reflect energy consumption at anchor while the higher ones are typical of cruising. Our energy needs while anchoring are usually less than our replenishment numbers so we can watch a bit of TV every day. While sailing, we usually have sufficient wind to improve the replenishment numbers for the wind generator thus balancing our generating capacity with our consumption. On low wind days we usually motor sail which adds the motor’s alternator to the equation.
We did cheat a bit in 2003 and added a Honda 2000 watt gasoline gernator to our inventory. We probably should ot have as we have only used it 3 times in three years. Stil it is nice to have just in case.
SUMMARY Jule III is balanced with energy generation equal to or exceeding energy consumption. Of course we wish we had more energy. We could have a larger refrigerator, more computer time, more TV, and better lighting. However, we are willing to compromise some of the niceties to be truly energy self sufficient! 