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Cruising yachts have to supply their own electricity when not tied to an umbilical cord at the dock. There are many ways to go about producing electrical power and storing it - engine-mounted alternators, gen-sets, solar panels, wind generators or water propeller-driven generators. Storage batteries also come in a variety of types and sizes. The more sophisticated the equipment, the more costly it is to buy, install and maintain.

When we started cruising, our electricity requirements were not very great: lights, radio receivers, water pumps and the windlass summed it up. I used to think that since we had to have the main engine, we may as well use it for charging the batteries. I could not justify the expense and extra maintenance of a generator for our needs.

As time went by, more equipment found its way aboard: radio transmitters, fans, GPS, computers, phones. So we added a solar panel, mounting it so that it could be adjusted to get the most of morning and evening sunshine, and a propeller-driven alternator to keep the battery charged when sailing on a passage. With a diesel heater stove that requires no electricity, and with propane cooking, hot water and refrigeration, we are still not big consumers of electric power, but as we slowed down and traveled less, we realised that it was not such a good idea to run a 75hp 4 liter diesel engine to top up batteries when the sun is not willing to help.

For economy reasons we are depending on a small house battery. The bigger the battery banks, the longer it will last under a given demand. But whatever the size of the battery, the power used has to be generated. So with a small battery you may have to charge the same amount in more frequent spells. However, batteries last four or five years, so when replacement time comes, the bigger battery bank costs more to replace. We found that a 90amp lead acid heavy duty automotive type battery handles our needs for twenty-four hours. We use an electronic voltage regulator that lets us get as fast a charge as the battery can handle when it needs recharging.

Six years ago I was under the knife to get rid of the "Big C" that had got a hold of me, and we realised that we would not be moving much for a while, therefore not motoring as often as we had been. We had to look at the options available to keep our batteries charged. Adding more solar panels can be cumbersome, and so can wind generators. None of these things come without considerable expense. Besides, there are times when wind and sun are not there to do the charging. There are some beautiful gensets available today, but they are very expensive, to say the least. So I looked at other options. The portable generators that were available were mostly intended to put out AC current, and if they did have a DC output, it was only 8 amps. AC to DC battery chargers are available but expensive too, if a high rate of charge is needed. However, we did carry a couple of spare 60 amp alternators. So I looked around for a stationary gasoline engine to drive one of those.

For NZ $500 I bought a new 3.5 hp Briggs and Stratton and made a soft mount bracket to install it permanently on our stern deck under a cover. The motor and the alternator are bolted onto a 1/2" plywood base that is itself bolted into four 4" long pieces of 1-1/2" rubber hose bolted on the deck to absorb vibrations. An inner cover made of vinyl flooring riveted onto a frame work of 1"x 1/8" aluminium flat bar serves to protect the unit from rain and absorb some of the noise when in use. An outer cover made of vinyl cloth fits on the outside to seal it from rain and spray when not in use. I also had to lead a pair of heavy duty wires to carry the charging load from the stern deck to the battery.

Soft mounts.

The little 3.5 hp would stall at more than 45 amps, but it did charge our battery for five years when we needed it. The flat head 4 cycle B&S was not a good buy. It started burning oil right from the beginning even though it came with a certificate of emission approval for California! And burn oil it did, more than the ancient two cycle outboards did at 25-to-1 mix. So it was dirty, and noisy when charging at 45 amps. Not only did it spew blue smoke but it choked itself with carbon deposits to the point of seizing its exhaust valve every few hundred hours of running. I installed a water-cooled exhaust to carry the noise and the oily smoke into the sea. But it was not good enough. So a year ago, for NZ $435 I found an imitation Honda stationary motor made in China to replace the B&S. This one is a 6.5 hp overhead valve with an inclined cylinder, a fraction bigger in size but with the same base fasteners and shaft size and position as the 3.5hp B&S. Much to my surprise I was able to unbolt the B&S and bolt the new one onto the same mounting base.

Chief's cover frame

This "Power Chief", as it is labeled, can handle the 60 amps at partial throttle, so is less noisy. But I made the mistake of charging at 60 amps for long periods of time and ended up burning the poor alternator. So a friend in California bought us a US $45 reconditioned (in Mexico) 80 amp Delco Remy alternator replacement and this one we are more careful with, charging at no more than 50 amps. For the final topping up of a charge we throttle back to a little over idle where fuel consumption and noise drop to minimal level. So far Chief looks happy after 15 months of service and 150 hours running...

To get back to the dollar aspect of this approach, here are some of the numbers. I'll use NZ dollars because that is what we are working with here. To convert it to US dollars, multiply by 0.78 at today's rate of exchange.

First to compare initial cost, solar panels start at NZ$600 for the smaller 3 amp ones, wind generators go from NZ$2000 up plus the installation that can amount to quite a bit, especially if you hire professionals to do the job. As for gensets, the sky's the limit. Some very 'cute' units are for sale here for NZ$14,000 plus installation.

The Briggs & Stratton and parts for the installation cost us approximately NZ$600 not counting my labour and we have burned a bit over 150 gallons in five years and 600 hours running. Even with NZ high priced gasoline, the first five years cost us less than NZ$700 for fuel and oil. So after five years our investment was still much less than the price of a wind generator.

Fifteen months ago we invested another NZ$365 for the new motor (we got NZ$70 for the used B&S) and NZ$60 for the replacement alternator. Gasoline has gone up in price - it was a little over a dollar per litre a few years back, it is now over a dollar fifty per litre and going up still. The last 150 hours running cost us about NZ$250 including oil changes. So after 6 years we have reached the shelf price of a wind generator...

With a bit of luck, we hope that Chief will keep running for a few years and cost us no more than a dollar fifty an hour to run. (Running the main engine would cost over NZ$2 per hour for fuel plus much undesirable wear.) On a yearly basis we need a half hour per day of charging with the generator. We don't use it much if at all in the summer months, but in the winters when the days are short we may need an hour or more per day unless we are on the move. This may not be the best way to charge batteries, but comparatively speaking it is a low cost approach.