D-400 wind generator

D-400 output graph


Current price is $2295.00 (+$99.00 shipping and insurance to the lower 48 states) including regulator, diversion load, brake switch, fuzes and installation manuals. Because the British Pound is at a low exchange rate, we are passing on this savings to our customers for as long as these favorable rates last. Price is subject to change without notice, so don't delay.

For someone that is already convinced that you need one of these units but the budget is a bit tight we have a 24V unit that has been rebuilt with the full kit for $1995 and a full 1 year warranty. Hurry, it won't last!

What is the Advantage of the D-400 Over Other Wind Generators?

The D-400 is a wind generator, designed for a variety of marine, rooftop or terrestrial applications. It is exceptionally quiet and vibration-free in operation, qualities that are of paramount importance for any wind generator operating in close proximity to people. 

The D-400 features a powerful 3-phase alternator, and computer-designed rotor blades optimized for low speed and very quiet user-friendly operation.

This innovative machine is extremely efficient in low wind speeds, yet is capable of sustained high power outputs of 500 watts and more in higher winds (see Cameron Murray's comments below).

Distinctive and elegant in design, the D-400 is superbly engineered for long, trouble-free service, and is available in either 12, 24, 48 and 72 volt variants.

Typical D-400 Output
10 knots wind speed produces 40 watts
15 knots wind speed produces 120 watts
20 knots wind speed produces 190 watts
25 knots wind speed produces 280 watts
32 knots wind speed produces 400 watts


NOTE: These figures are representative of performance at sea level when operating in an open, turbulence-free site.

Link to D-400 users manual;


Compare D-400 Output in 15 Kt. Wind With Some Other Wind Generators *

Aquair,  wind mode 3 amps, D-400,10 amps. 

Ampair Pacific 100 < 2amps  D-400,10 amps

Aerogen, less than 1 amp D-400,10 amps

AirX Marine, 3.5 amps, D-400,10 amps

* From manufacturers published sources at 12 volts

See Some Comments From Our Customers:


You too can install a wind turbine on your transom for reliable, added battery charging!

Here are some examples;

 WandererWandererWandering Dolphin

Stop Burning Dollars!!


How Does the D-400

 Save me Money?

A Comparison Between the Cost to Produce Power Using Your Engine Alternator and a D-400 Wind Generator

Yanmar engines from 21 to 54 horsepower average cost is $9,200.00. 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 $1,000.00 to the installation. Maintenance will be about $250.00 per year for oil, filters, belts, zincs, antifreeze etc., not counting labor.

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 horsepower]

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 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 per 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.

Let's assume a hypothetical battery bank of 600 amp hours at the 20 hour rate. If we discharge 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.

Further, assuming that all the power produced is going to charge the battery (no ship's loads), then (350 amp hrs/ 84 amps) = 4.16 hours is required to produce our desired recharge. (4.16 hrs x 0.24 gal) = 0.9984 or about 1 gal per recharge of 350 amp hours. A bit more research indicates that $5.00 per gallon is a conservative estimate of diesel fuel cost throughout the world. If you only use 100 amp hours per day (a low estimate) you will have to run your engine 4.16 or more hours every third day or 122 times per year at $5.00 each time, consuming $610.00 worth of diesel per year.

The real number is at least 1.5 times that, or $915.00. Add the annualized cost of the engine, alternator system and maintenance ($1250.00) the cost per year to produce our required recharge is increased to either $2,165.00.

A D-400 with regulator and diversion load costs about $2,600.00. In a 15 knot wind, operating ½ time, or 12 hours per day, will produce 100 amp hours per day. ($2500.00/ 10 years) = $250.00 per year or about 11% of the cost of producing the same amount of power with your engine, not to mention wear and tear.

As a result, you will pay for the D-400 in a bit over 12 months compared to the other recharge method. After that it is free, with no noise and it doesn't smell bad.


Why do I Need a Regulator and Diversion Load with my D-400?

Nobody has a memory good enough to be a charge regulator. If you forget to stop your wind generator when your batteries are completely charged you will most likely over charge them, causing excessive gassing and dry out the cells. The batteries will be ruined, and you will not be happy. Further, you will be producing excessive amounts of explosive hydrogen gas and causing the batteries themselves to heat. In the case of AGM (absorbed glass mat) batteries you may trigger highly dangerous thermal runaway with damage not  only to the batteries, but surrounding structure and personal injury.

We have tested and tried many other regulators. For reliable, safe opperation our choice for the D-400 system is the Flex Charge NCHC with diversion option sold as part of the D-400 kit. For the reasons recited in the previous and following paragraphs we do not sell wind generators only to end users. Industrial and research applications may be excepted upon compliance with conditions acceptable to Southeast Marine.

The D-400 is a very powerful permanent magnet alternator. As long as it is turning it is producing power. Because the D-400 has a greater magnet mass, it does not stop producing power at 25 knots of wind, as do most other wind generators. The D-400 will continue to produce power in much higher winds. Output currents of 60 or greater amps have been reported. Again, no one has a good enough memory to be a charge regulator. A set of quality batteries with 750 amp hours of capacity costs between $1,500.00 and $2,000.00. When discharged to 50% of capacity, at 50 amps charge current, those batteries will require about 7.5 hours to completely recharge. If your D-400 is experiencing very high winds, and you are not there to monitor and shut down the generator, at the least, you will very quickly destroy a very expensive battery bank. You may do a lot more; The batteries will be producing excessive amounts of hydrogen gas which is very explosive. The possibility of explosion and fire is present. As the principle western hemisphere distributor for D-400, Southeast Marine has carefully matched an appropriate regulator, diversion load and braking switch to the D-400. Fred King, P.E and Larry Janke Sc.D  tested many regulators and chose the FlexCharge NCHC with diversion option as the optimally engineered combination, together with a 600 watt diversion load and braking switch.

For your safety, Southeast Marine and its dealers only sell D-400s to end users as a kit consisting of the D-400, regulator, diversion load, braking switch and fuses. If anybody tells you “you don't need a regulator” ask to see his products liability insurance policy. The following explains it in more detail.

In applications with multiple charging sources, such as a cruising sailboat, conflicts can occur between the various chargers, alternator, AC charger,wind generator, water generator and solar panels.

Charging sources, such as the D-400, and other permanent magnet charging devices require a diversion load to absorb the power being generated when the batteries are fully charged. Wind and water generators are the most common. It is necessary that the diversion load be connected only to the permanent magnet device and not to the battery. Otherwise, when the alternator or other charger is operating, the other charge regulators will "see" the diversion load, and continue to put out power, in an attempt 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 and the reasons for diversion loads and specialized regulators see the following links.


Permanent Magnet Generators and Diversion Loads




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