DuoGen - March 2004 Newsletter
I’m sure some of you remember a day when yachts carried very little electrical equipment. Thirty years ago, you would find a depth sounder, maybe an RDF – and a transistor radio was all you needed for navigation and on-board entertainment!
How things change. There has been a huge technological advance in all areas of life, and now most yachtsmen won’t leave their berth without their:
Computer plotting
Autopilot
Refrigeration
Radar
Water maker
VHF and SSB radios
Computer games!
The energy for all this, and more, is drawn from the ship’s batteries.
So exactly how much power do you use on passage?
Here’s how to find out by doing an Energy Audit.
Calculating the load for DC demand
• List all onboard equipment together with its power rating - get the amperage it draws by dividing voltage into wattage.
• Work out when and how long each bit of equipment is switched on.
• Develop figures for day and night sail, and arrive at a daily passage value.
• In the same way, develop figures for harbour or anchor (most usage is highest on passage).
• You should add 10% as a contingency to allow for sundry losses and inefficiencies.

In our experience, 100 – 250AH per day is typical. (Remember, some equipment, such as fridges, cycles.)

Your Energy Audit informs how much Battery Capacity you install.
Bear in mind the useful capacity of the bank will only be about 50% of its stated capacity because
a) it shouldn’t be discharged below 70% and
b) it is unlikely ever to be charged much above 80%

If you have 400AH installed battery capacity and your daily passage requirement is 150AH, the combination would work. Given the above scenario, however, many would argue for greater capacity, although the charging regime to be adopted will have a bearing on this.
• The other factor to consider is this. The faster you withdraw current, the less of the batteries’ capacity you can access. For example, there is more retained capacity in the battery if you draw 5 amps for 20 hours rather than 10 amps for 10 hours.
• Batteries do self-discharge. This loss is temperature dependent, and is particularly noticeable in the tropics where 4 – 5% loss per month is not unusual. Trickle charging devices are useful to compensate for these losses and keep batteries ‘in the pink’.
Temperature also effects overall battery efficiency, with a reduction as temperatures increase. Even in ideal conditions, you never get out of a battery what you put in, and typical losses are 10 – 15%.
• Batteries will only accept charge at a certain rate – they are effectively self-limiting.
However powerful the charging source, it takes time to fully charge a battery bank. You are reversing a chemical reaction and that can only happen at a finite rate. So if you run your engine or genset for an hour a day, it will replace power but it will never fully charge the batteries.

However, if you can charge your batteries as you are using power, you can keep them at a healthy level. They never become too depleted, and you are only reversing that chemical reaction a little at a time, and continuously. This is how DuoGen, and other renewable energy systems, are so useful.

Order your DuoGen now, and keep your batteries in a
healthy state!
Don’t risk running out of energy as you sail.


 

 

 

 

DuoGen in The Netherlands and Belgium

Available from Eco-Energy Rietpol, at Spaarndam
www.eco-energy.nl

 
   

A word on Wind Power

  
How much power a wind generator can produce depends primarily on the rotor size and the wind speed.
However, people are sometimes disappointed with performance because they measure the wind speed at the mast head rather than at the turbine, which explains the lower than expected output. 		 
   

A word on Water Power

  
Towed water generators are a great under-used resource. As water is 800 times denser than air, a lot of power is produced even from a small impeller, and, unlike wind, it is steady.
DuoGen deployed in water mode while you sail will produce far more power than a wind generator.
 
Order DuoGen.
Contact us today!
email: sales@duogen.co.uk
phone: sales on 01623 827829
write: Eclectic Energy Limited, Edwinstowe House, High Street, Edwinstowe, Nottinghamshire NG21 9PR, United Kingdom

Safe Sailing!

If you do not wish to receive further emails about DuoGen please send an email with "unsubscribe DuoGen" (without the quotes) in the message body to news@duogen.info .
DuoGen Home Page