Your Questions About Wind Generators For Boats
Linda asks…
Is there any safety issues in using a non marine grade generator on a boat?
The difference between a marine grade 5kw generator and a common home or job site use 5 kw generator is thousands of dollars. I understand salt being an issue but I am on freshwater. As long as I am not spilling fuel are there any safety concerns?
admin answers:
You have more then exhaust fumes to worry about. If the generator has its own gas tank it will be vented into the boat (if you have it in the boat). Getting enough air to cool it would be a problem and how would you get the exhaust out. You could try it on the back of the boat but if there is any wind you have to worry about the station wagon effect, wind swirling around and pulling fumes into the boat. Not to mention it getting wet if a wake hits you from the back. I don’t think you would do to well if you got boarded by the police or the USCG as that is not an “approved device” How about putting in an inverter and a dedicated battery for 110 volts instead?
Carol asks…
Will a trolling motor generate electricity and charge a battery if it is pulled thru the water?
Specific application I’m looking at is using a high thrust trolling motor on a small sailboat for the auxiliary propulsion. Research indicates this will work great. However, the various sites advise using solar/wind/ or shore power for recharging.
Suppose the motor was left down, we raised the sail, and the prop began to freewheel. Seeing as how this is a DC motor, wouldn’t it start generating electricity? Has anyone tried this? What type of controlling circuitry would be needed if any to charge the house batteries?
admin answers:
Here is the Biggest problem with the trolling motor generator…Its not with the motor but with the capture area of the prop…Lets do the math here real quick …I promise not to take to long…If your trolling motor uses 10 amps at 12 volts thats about 120watts …756watts is about one horsepower,……. To get enough drag surface on the prop you need about 60 sq inches….120/756=.16hp or 480 sq inches per hp….more or less..so thats a pretty good size prop lets say 5″ x 12″ now to get it to spin you need a very easy rotating motor/gen set if its a permanent magnet type you have a problem getting it past the first pole is pretty hard…now lets look at rpm for a moment normally your motor cranks out that 120 watts at say 500-600 rpm to get a sail surface relationship and pitch to get your 12 vdc back… Your gonna need to have one heck of a pitch or loose your voltage for lack of rpm.. So I would say this …your idea of using the regenerative power of a dc motor to make a little wattage is quite sound ..However using a trolling motor made to puLL your boat might not be as efficient as some other means…Keep working on the idea though try using a right angle gearbox being driven by a floating paddle wheel ..or perhaps a flexible driveshaft underneath the boat with a helix coil driving an inboard alternator. Regulation for all the voltage is as easy as pie… A couple of big caps and one transistor and 30 minutes and you can build a regulator for nearly any thing up to 200watts…Ever hear of the 12v Light bulb from the old days being used as a regulator? See didnt even need a cap for that one….Anyhow have a good day from the E…
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