Get 12 volts out of a spinning trolling motor?

[tri again]

Been trying to get electricity out of my creek. One crossing is a 42 inch pipe with about 30 inches of water screamin' through it.

I mean, it's strong enough to pull your boots off and impossible to stand in without going for a fast ride downstream.

One thought is just hang a trolling motor in the slip stream and hope it acts like a dc motor and puts out 12 volts.

Thinking IF that works, it should be sorta waterproof and I could mount it somehow on a slide or float so it goes up and down with the water level.

Yupp, water frequently overtops that culvert by a few feet.

Was thinking it might be easy to check voltage output if someone has ever left the troller in the water when using their gas engine.

Maybe the electronics would prevent it so I could look for a trolling motor with a smashed control unit and just use it as a direct to motor setup.

Seems a shame to see all that power just slipping by.

Thanks

[hoosierlogger]

I am no electrical engineer, but I think you might have to switch some wiring to the armature and field coils inside the motor housing. Would be cool if it works.

[Scootertrash]

Not an electrical engineer either, but I think you would need a "motor" designed for electrical output, like a car alternator or a stator/flywheel set up like on small engines. I don't think you can rewire a trolling motor to output electricity, it's designed to receive an input of electricity to run, and it doesn't have a charging system (I don't think they do anyways), which is why you need to recharge the deep cycle battery.

Now, I don't pay too much attention to trolling motors since I don't fish, but I don't believe they are capable of recharging the battery that powers them. If I'm wrong, some one please correct me.

Depending on the output voltage you wanted you could use the windings and housing off of a generator, put a "waterwheel" on the shaft and see if it would spin fast enough to generate the voltage you wanted.

[tri again]

Was just thinkin' goofy because I have an old triumph car with a generator.

Fooling around with the antique voltage regulator, I shorted it backwards and the generator would spin like a motor with 12 volts TO it.

I think I had a harley golf cart with the similar generator / starter deal.

Put juice (12 or 6 volts) to it to start the cart and it would magically become a generator to charge the battery.

Just what I need.
Another project for springtime.

I was really hoping a half dead or broken trolling motor would be the answer.
I wonder how much resistance there is to simply spinning the prop?
Never been closer than 10 feet to one.

Wonder if I'd get in trouble for checking one out at the store....with a voltmeter..
I better find something else to worry about.

Thanks you guys.

[hoosierlogger]

Lawn mower starters double as generators. This might be possible.

[Scootertrash]

Good idea. I think you'd have to go with an older one because the newer starters I've put in are just a starter. The engines have a charging coil behind the flywheel. Those are newer Briggs, Tecumseh and Honda motors.

My guess would be to find the proper manufacturer and year.

[RIDE-RED 250r]

Pretty sure a DC motor will readily generate power by spinning it manually if it is spun fast enough. AC motors I believe are a different story.

I used to work as an in home tech and treadmills were something I worked on. We used to test the DC treadmill motors bu disconnecting the power wires and propelling the treadmill manually by walking on it and reading the voltage output coming out of the DC motor with a meter.

Now, I am more of a small engine guy and treadmills was something I learned to work on specifically with that job.. I am not as experienced in it and wasn't as comfortable with it. But I do specifically remember checking those DC motors that way.

I think the real question is, will your water supply be able to spin the trolling motor prop fast enough to generate any significant amount of DC output. That little prop spins amazingly fast to move a fishing boat at that trolling motors realtively slow speed. I think you would have to modify/replace the prop with a more egressive design that is more capable of being spun at great speed by flowing water to get it done.

[Scootertrash]

I think you would have to use a system much like the old flour mills. A large wheel in the water mounted to and spinning a small diameter shaft for the generator. Maybe?

[kb0nly]

If you got that much waterflow a simple waterwheel setup will be much more efficient turning a permanent magnet generator. I know a guy with a cabin out in the middle of nowhere that runs a 2kw permanent mag generator from a waterwheel on a stream, that dumps to a large inverter made for wind generator setups, it charges a battery bank and output is AC 120v. The waterwheel isn't huge, about three foot diameter, he made it himself. You could straddle that culvert with a mounting structure made of a couple poles and a waterwheel in the center of the flow, i bet you would get some good speed off that and very useable power. Look up permanent magnet generator on youtube, there is some guys building some really amazing ones now, they don't need a lot of torque to spin them up either.

[Mosh]

Old 80's car alternators and a battery are very simple to hook up and fabbing a paddlewheel and post to mount the Alternator would be easy enough i think. That would get you 14 volts and about 45 amps. You could always mount an inverter to the battery. I too have been doing research on self power generation. Alternator wires and battery may cost around 100$ or so.

[TimSr]

DC motors will generate DC voltage when manually turned. Voltage varies wildly based on RPMs. Current is relatively low. They also require a great deal of torque to turn.

I've never examined a trolling motor, but I doubt they are direct drive. If you can turn the motor via the propeller, I doubt you could turn it with just water flow.

AC generators (alternator) require a lot less force, and put out a lot more current. Mosh's car alternator idea is spot on. Water is more constant, but if you don't have a stream handy, it doesnt take much of a fan blade setup, with a pulley and belt to an alternator to keep a 12v DC battery pack charged via wind power. Can be done with all junk yard automotive components and automotive batteries. Turbine can be made from a number of articles or easily adapted from barn ventilation fan.

[wheelsforheels]

I have seen a squirrel cage out of a forced air furnace used as a water wheel. Didn't see the rest of the set-up but I like the idea of a car alternater also.

[wheelsforheels]

Some cages have the motor attached directly to the fan while others have a pulley that connects the fan to the motor via a belt. It is already mounted on bearings. Once in use you may have to pull it out once or so a year to clean up and paint. The belt would allow for positioning the altenater away from the water source. I used to have a link for homemade permanet magnet generaters. Let me know if you want me to try and find it. I've changed browsers since I had it so it will take some finding.