Well it couldn't last forever, the Pound is going up and the Dollar is going down. Transportation costs and customs processing fees have increased so we have to raise the price.Prices advertised are for units in stock and may vary with reorder from the manufacturer.

Delivery from stock FOB Scappoose, OR. Prices include  shipment, brokerage and customs charges from UK

The price 24 and 48 volt units will be higher as they are a non stock item and shipping costs will be greater.

"For serious cruisers, this wins...our Premium Product Award." Sailing Today August 2002

We picked out some of the comments made in Tim's report on his comparative test of nine of the best known wind generators on the market.   Read the full report in the August 2002 Edition of 'Sailing Today'.   The article begins with an overview of wind generation in general, emphasising important points to consider when you are choosing a renewable energy battery charger.   There are full descriptions of the wind tunnel test of all the machines, output graphs and information, followed by a table which allows you to compare specifications, efficiency etc. at a glance.   This is a 'must read' for anyone considering the purchase of a wind charger.

What Tim Bartlett says about DuoGen   Design and Engineering "radically different" "a very cunning angle drive unit" "Aerodynamically, it's good" "A radical concept, robustly engineered" "very low centre of gravity"   Practicality "the alternator's significant weight isn't likely to have much adverse effect on the stability of the boat." "the wind turbine needs to be easy to mantle, dismantle, and remantle...and it is." "It takes a matter of seconds, rather than minutes." Tim awarded DuoGen a maximum five stars for functionality, which covers, says Tim, "ease of installation, ruggedness of construction, size, weight, noise, and so on."   Performance "In 10kn of wind... its efficiency was an impressive 53 per cent." Tim awarded DuoGen four out of five stars for performance.   Cost "Its initial price looks high, but it will cost next to nothing to install, and comes complete with its water drive facility."

We say:

When you purchase DuoGen, unlike the other machines Tim tested, you have two machines:

• in harbour, a sturdy and reliable wind generator that won't keep you (and you neighbours!) awake at night
• a super-efficient, deployed-in-seconds, totally unobtrusive towed water generator that can provide enough power to run all your onboard equipment as you sail.

• DuoGen vs Towed Impeller Generators

  Many yachtsmen consider towed water generators too much trouble, even though this is an efficient way to get a lot of energy out of the wind.
  These are some of the comments made by the skippers who do use them.
  All quotations have been taken from the ARC Survey Report featured in Yachting World magazine, July2002.

  Quotation about towed impeller		How DuoGen is different
  "Good except the rope kept getting round the propeller as it jumped, surfing down waves." "... line was knotting up in a big way."		This can't happen with DuoGen water mode, because it doesn't rely on towing a heavy impeller on 30 metres of rope, and operates in the top 50 cms of water, within the same wave as the yacht.
  "The towing log-propeller disappeared in the water. We presume it was eaten by a shark!"		Again, this is very unlikely to happen with with DuoGen water mode, for the reasons given above, unless you encounter a particularly bold shark!
  "... the towing line is prone to snarl up when being paid out or taken in, inclined to jump out of the water.."			This is not a problem with DuoGen (see above). You can deploy the water mode in seconds, by lowering the unit into the water while holding the recovery lanyard. Recovery is just as simple.
  "... the drag slows a boat."			DuoGen causes 30% less drag, amp for amp, than alternative machines with long tow ropes.
  Water impellers are "generally ... used on mid-range boats of 40ft and under, as the power generated is inevitably a smaller percentage of the requirements the larger the yacht."		We believe that every little bit helps, and that the best way to keep your batteries charged is to use a variety of methods, especially if you have a large energy requirement. Having said this, DuoGen has the advantage over the alternative machines because the water mode carries on generating power at the higher speeds of which larger yachts are capable. We have measured an output of 20 amps at 9 knots.

   

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Wind mode specification

Water mode specification

A Comparison Between The Cost To Produce Power Using An Engine Alternator And DuoGen 2 Water And Wind Generator

A survey of several dealers indicates that the average yearly cost of the engine typically found in a sailboat equipped with a high output alternator and regulator including maintenance amortized over 15 years is about $1000.00 per year, assuming 15 year or 7500 hour life. 

Yanmar engines from 21-54 horsepower average cost is $10,200.00. A Balmar 60-YP-100 package consisting of a 6 series 100 amp alternator, a MC 612 regulator and alternator/battery temperature sensors will add about $ 1000.00 to the installation and maintenance will be about $250.00 per year for oil, filters, belts, zincs, antifreeze etc. Not counting any labor if you do not do the work yourself.

Total cost for 15 years, $15,000.00

$15,000/7500 hours = $2.00 per hour operating cost not including fuel.  

1.93 horsepower is required to produce 100 amps in a perfect world. 

 100 amps x 14.4 volts = 1440 watts. (1440 watts/746 watts per horsepower) = 1.93 horse power. However the world is far from perfect, in reality it will take at least twice that amount of power or 3.9 horsepower to produce our desired 100 amps because of alternator/battery inefficiency and belt loss.   

 A new diesel engine or one with relatively low hours and in good condition will use 0.44 pounds of fuel per hour to produce 1 horsepower. (0.44lbs x 3.9 HP)  =1.7 lbs/horsepower hour. Diesel fuel averages about 7.2 pounds per gallon. (7.2 lbs per gal/1.7 lbs) = 0.24 gallons per hour an older engine or one in not such good condition, will use even more so let’s round it to 0.25 gallons per hour   

 Let’s assume a hypothetical battery bank of 600 amp hours at the 20 hour rate. If we use 300 amp hours, (50% being the maximum we should discharge a battery), we need to return about 350 amp hours to satisfy the first law of thermodynamics (you don’t get anything for free). When it is hot our 100 amp alternator will produce about 84 amps at 4000 alternator RPM or about 1600 engine RPM assuming a 2.5 to 1 pulley ratio.

(350 amp hrs/ 84 amps) = 4.2 hours to produce our desired recharge. (4.2 hrs x 0.25 gal) = 1.05 or about 1 gal per recharge of 350 amp hours $5.00 per gallon is a conservative estimate of diesel fuel cost throughout the world. 

Per hour cost of engine operation = $3.20 ($2.00 amortized engine cost + $1.20 fuel) 

  If you only use 100 amp hours per day, a low estimate, you will have to run your engine 4.2 or more hours every third day or 122 times per year at $3.20 per hour or $1600.00.  

A DuoGen 2 Water and wind generator with regulator and diversion load costs about $4300.00 or less depending upon the choice of diversion load. Let’s assume that in a year you sail 25% 0f the time and sit the rest. At 6 knots boat speed the DuoGen 2 will produce 192 amp hours in 24 hours of sailing, or about 60% more than our required 120 (100 amp hours per day usage plus the additional 20%). So now, unless you need to motor for propulsion, you do not have to run the engine at all. Another money saving benefit since you do not have to cycle your batteries, they will last substantially longer.

When you get where you are going, and convert the DuoGen 2 to wind mode you will continue to save money.   In a 15 knot wind and operating half  time or 12 hours per day the DuoGen 2 will produce 75 amp hours per day, or 65% of our required 120. As a practical matter, you should use less power when not underway and some cruisers report that the DuoGen in wind mode provides all the power they need.

The DuoGen is working great. My diesel engine went out during the crossing from French Polynesia to American Samoa . When we anchored in Pago Pago , I ran solely on DuoGen wind power for four weeks -- fridge, DVD movies and all! On passage, we run computer, radar, fridge, et al, and the hydro has kept us topped off the whole time. I just can't say enough good about the DuoGen. 

Chris Burns
s/v Wind Dancer
Currently in: Apia , Samoa

 But even if we still need to supplement with some engine time (a couple of solar panels wouldn’t hurt) we should only have to make about 135 amp hours every 3 days.

100 amp hr per day usage x 1.2 =120 amp hours to be returned

75 amp hours from DuoGen in wind mode= 45 amp hour deficit

300 amp hours/45 = 6 days between recharges at 50% or 42 days x 4.2 hours =176 hours

176 hours x $3.20 = $564

 DuoGen 2 a regulator and diversion load will cost about $4300.00 USD ($4300.00/ 10 years) = $ 430.00 per year or $1170.00 per year less than using your engine driven alternator, not to mention wear and tear.

In other words you will pay for the DuoGen 2 in about three and a half years compared to using your engine. . After that it is free with no noise and it doesn’t smell bad. Again since we are not cycling the batteries so deeply our battery life will go up.

 If for example we are using Rolls 4000 series batteries, (1350 cycles at 50% discharge), and we only discharge to 75%  battery cycle life will increase to over 2000 cycles.

 If we add 150 watts of solar panels, we should get about another 60 amp hours per day so we are home free. The panels and regulator should cost about $ 800.00 and if we divide that by 10 years we have added $80.00 per year to the equation or a total of $480.00 per year as against $1600.00. Further since engine hours can be greatly reduced, maintenance costs and headaches will go down and engine life will go up. 

 This is not an argument against installing a quality high output alternator; someday you are going to need one, but with high fuel price, and environmental impact, the numbers listed above multiplied times thousands of boats is significant. 122 gallons of fuel per year multiplied by 10,000 boats is a stagering 1,220,000 gallons of fuel, or $6,100,000.00 at $5.00 per gallon.

  Do I need a Regulator?

 In applications with multiple charging sources like a cruising sailboat, conflicts can occur between the various chargers, alternator, AC charger, wind generator, water generator and solar panels. With charging sources such as the DuoGen, and other permanent magnet charging devices requiring a diversion load to absorb the power being generated by the device when the batteries are fully charged, wind generators being the most common, it is necessary that the diversion load be connected only to the permanent magnet device and not to the battery as is common with most wind generator regulators. Otherwise, when the alternator or other charging source is operating, without diversion isolation, the other regulators will "see" the diversion load, which may be as much as 500 watts for larger wind generators, and continue to put out up to 40 amps trying to meet the demands of the diversion load. In other words, the alternator or other charger never stops charging which leads to overheating and premature failure, as well as wasting power, creating a continuous heat source from the diversion load as long as the other charge source is operating. For a complete description of the recommended regulator see the following link.

http://www.semarine.com/store/product.php?productid=345&cat=84&page=1

Compare the above DuoGen output with the output published by some other water and wind manufacturers;*

Ampair/Aquair

At 6 knots hull speed, Aquair 100 Towed turbine 2.5 amps, DuoGen 2,  8 amps.

In 15 knot wind;

Aquair,  wind mode 3 amps, DuoGen2, 6 amps. 

Ampair Pacific 100 < 2amps  DuoGen2, 6 amps

Aerogen, wind only, no water mode available,  less than 1 amp DuoGen2, 6 amps 

AirX Marine, wind only no water mode, 3.5 amps, DuoGen 2, 6 amps

* From manufacturers published sources at 12 volts