Onboard power

Take charge

It's fair to say I would prefer to live on my boat than in my house and, on occasion, I get to do exactly that. With modern communications I'm able to run my business efficiently and effectively from my floating abode as the water laps at my marlin door and the stirring views unfurl from the swim platform. As long as I get to go ashore every day for a few hours, the dog receives his required three walks and I don't feel like a hermit festering in my favourite fibreglass abode.

Spending days and night aboard gives me time to see how my boat fares as a standalone unit. And when my wife and baby are aboard for weekends and holidays, they can be provided with hot showers, sufficient lighting, warmth and good food without the need to scuttle off for a marina to recharge. Some might say I am a sensitive new-age mariner but really, I just get a kick out of having technology working as it should.

Now to the point of this article: whether you have an old or modern boat, power requirements are increasing as the RV and marine markets demand more of the domestic appliances and equipment we take for granted at home. Happy holidays on a modern, well-equipped boat now require a continuous and/or regenerating power supply for both DC and AC equipment.

So how do you make certain that you will always have enough instant power or stored onboard energy to cover every situation? It's time to take a look at modern energy-creating devices. Think of them as insurance for a happy week's holiday afloat.

HOW MUCH IS ENOUGH?
In my case, I need to have sufficient power to run fridges, freshwater and other pumps, the mobile office, electronics, engines, dishwasher, lighting, hot water, electric stove and BBQ.

Therefore, keeping my batteries topped up is critical.

In an average boat, refrigeration is the main user of DC electricity, probably followed by lights. Interior and exterior LED lighting is a smart alternative to fluorescent or incandescent bulbs. These could reduce your lighting power requirements by 80 per cent.

Switching your boat to 24V and using 200amp 6V batteries for the house supply can effectively double (or better) the available energy for the space taken by the batteries. My own boat, a 43ft cruiser, uses a whopping 120 to 150amps in DC per day when we are out. Approximately 75amps is used for refrigeration and 40amps for the evening lighting. My floating office uses just four amps per hour, mainly to run the computer.

Here are some smart ways to generate onboard power.

SOLAR PANELS
Year-on-year advances in solar panel or photovoltaic technology forge ahead in a most promising way. But the key thing to remember here is that output is in proportion to the size of the panel and the amount of sunshine each day.

I have a very large 24V 160amp solar panel on the front deck of my cruiser where the tender would otherwise ride in its cradle. During the Sydney summer it theoretically puts out 50amps of DC during an average day. This is more than enough to power my fridge.  In winter, the fridge runs continuously on low.

For the past two years, I have never turned the fridge off and the battery monitor says that the batteries are, on average, 85 per cent full. So the solar panel has been a great solution, especially as my boat is on a swing mooring. However, it is not enough to run the fridge and the eutectic coolbox together.

DIESEL GENSETS AC
There are many different brands of diesel-powered AC generator, or gennie as we affectionately call them, including Diecon, Fischer Panda Kohler, Northern Lights, Onan and Westerbeke to name just a few. Typically in recreational boats, they range in size from about 3kVa to 22.5kVa. Some run at 1800rpm and others at 3000rpm. All of them are engines, so they make noise and vibration, although new generators are nothing like those of yesteryear. Still, fellow boaties will hear them if you don't, especially in a quiet bay at night.

Yet there is no more convincing way to make domestic levels of AC power than with a generator, which is still mandatory on most boats with air-conditioning as it typically demands 1400 to 2000W. However, as you will see further down this story, DC air-conditioning units are available.

Meantime, despite what you may think, gennies don't use that much fuel. A typical four-pot 9kVa Onan at 50Hz, which is the Australian AC output, runs at 1500rpm and uses from 1.9lt/h at half load to 3.8lt/h at full load.

Note also that watermakers require about 3000W or 3kVa to run and even more on start up, so be careful when sizing your genset if you plan on fitting one. And, generally speaking, elements draw the most power which is why yachts tend to go with gas.

But did you know that a water-cooled genset's coolant can be plumbed to heat the hot-water tank? Webasto has a dual-coil water heater that uses coolant from the main engine or from your gennie. This way, you can fit a smaller generator and scavenge the heat for hot water rather than needing it to run the 240V element. Very clever and very energy efficient.

Two other things in favour of a diesel generator are the safety aspect of the fuel and its commonality if you have a diesel-powered boat.

PETROL GENSETS
These are often of similar size and output to a diesel genset, however, there are also some very handy portable gensets putting out up to 2.5 kVa. These can be removed from a hold, plonked on deck and run for brief periods when power is needed. The better portable gennies are reasonably quiet and vibration free. Some have a modest 12V battery-charging system too, although a more practical way to go is to connect it to a high-output battery charger.

Remember to do your maths: a 1kVa genset may have trouble powering a 50amp 12V battery charger operating at full capacity. Still, for about $1000 all up, portable petrol gennies are an effective and economical way to make AC power.

DC GENSETS
The advent of high quality marine inverters from manufacturers such as Victron and Mastervolt mean a genset is no longer required to run the kettle, TV, or stove. Inverters can output up to 5kVa each and can be linked. Many boats could have their AC requirements serviced by an inverter. Disadvantages include the relatively high cost and requirement of a larger battery bank.

A DC genset is a smart alternative. As its name suggests, a DC gennie makes DC current that is stored in your batteries. Think of it as a battery charger capable of outputting high DC amps. With a DC gennie installed on your boat you can run a DC air-con unit in the cabin.

More on DC air-conditioners in another story; suffice to say, these nifty units keep you comfortable on even the hottest tropical day!

WIND & WATER GENERATORS
I have only seen one wind generator on a motorboat and that was in NZ. However, cruising sailors embrace the windmill as a worthy way of providing DC power and a windvane can, in fact, be all you need, especially in windy latitudes and seasons when a prop will create impressively high DC output. If you have the space, a large solar panel and a wind generator make an ideal DC-generating combination.

(ED: Some things to consider with windvanes: a doubling of the propeller diameter creates a theoretical fourfold increase in generator output, but a doubling of windspeed produces a theoretical eightfold increase in output, and, generally speaking, you need at least seven knots of wind to make most windvanes work and above 10 knots their output is determined by blade size. Also, windvanes can be noisy and a suitable position away from living areas has to be considered to reduce its constant ambient level.)

FUEL CELLS
I first saw these as a prototype at a marine trade show in Amsterdam three years ago, but only now have they made it to market. They are about the size of a 1.5kVa Honda petrol genset and output a staggering 130amps DC a day per litre of methanol.

Methanol is $7.50 a litre, so it's far cheaper than running the genset all day! These units are fully automatic and turn on and off as dictated by the battery voltage. In fact, fuel cells are so interesting I will be writing about them another day. Cost is about $6000 including 10 litres of methanol.

GAS
Kiwis love gas on boats, at least that's what I've been told on visits to NZ boat shows, yet the Australian boat market seems to go the other way. Of course, most yachts have gas bottles, but not too many have gas-powered charging capabilities.

But in many respects, gas is an efficiently stored, high-energy fuel perfect for cooking and refrigeration. Just keep the fumes out of the bilge by storing cylinders above decks with a drain to vent escaped or leaking gas overboard. LPG gas is heavier than air and will find its way into the bilge.

Many portable refrigerated coolboxes have three-way power - AC, DC and gas. A gas fridge will use about 300 grams of gas per day, meaning an 8kg bottle should last far more than your week's holiday.

Galleying gourmands will also feel at home using a gas cooker and oven, since it's little different to what you have at home.

I trust this has given you an indication of the types and combinations of power generation systems on the market. Some are relatively free to operate once installed.

For my money, if you have the space, a 120amp (12V) or 160amp (24V) solar panel with an intelligent regulator is a good place to start. But if you have limited space and are happy to use an inverter for AC power requirements then fuel cells just have to be the way of the future.

* Scott Fuller is a boating enthusiast and principal of a Sydney-based marine distribution business.    

AUSTRALIA LOOKS TO SOLAR POWER
The Australian Trade Commission (Austrade) coordinated a strong Australian solar business presence at the APEC Photovoltaic Conference in Taipei from October 7 to 9. The significance of the conference is highlighted by the recent release (September 24) of a United Nations Environment Program (UNEP) report that predicted investment of $US630 billion in sustainable energy implementation would create 20 million jobs globally by 2030.

Austrade's regional director for North East Asia, Laurie Smith said the APEC Photovoltaic Conference offered a platform for Australia's innovative solar energy companies to connect with the potential of increased renewable energy implementation in APEC member economies.

"Climate change is a global challenge offering lucrative opportunities for Australia's sophisticated solar technologies," said Smith.

"The UNEP report predicted the manufacture, installation, and maintenance of solar panels alone will add 6.3 million jobs globally by 2030, reflecting strong rising demand for photovoltaic technologies and solar panel manufacturing as well as related services trade, such as education and training.

"APEC member economies represent 41 per cent of the world's population, and have the largest combined solar cell production capacity in the world, which offers Australian solar innovators strong scope to build partnerships to win business in North East Asia and beyond.

"China has mandated that renewable energy must account for 15 per cent of total electricity generation by 2020, requiring an estimated $A350 billion in investment," Smith said.

Dr Richard Corkish, head of the University of NSW Photovoltaic and Renewable Energy Engineering School - a world leader in converting sunlight into electricity using photovoltaic solar cells - delivered a keynote speech at the Photovoltaic Conference.

Other participants in the Austrade mission include the Australian National University Centre for Sustainable Energy Systems, involved with the development of SLIVER Cell (TM) photovoltaic technology, which uses just one-tenth of the costly silicon used in conventional solar panels while matching power, performance and efficiency.

Professor Andrew Blakers and Dr Klaus Weber won the Australian Institute of Physics' Walsh Medal for their work inventing the technology.

"The mission will raise the profile of Australia's clean energy capabilities, promote Australian innovation, and connect Australian companies to key industry players and customers," said Smith.