# Weedeater powerd Alternator?



## thudpucker (Jul 31, 2009)

:wink: Thinking about being out in the boat all day with only a trolling motor.
So you pull up on the beach to make a meal and crank up the Weed eater powerd Alternator and charge the battery while you fixing dinner.

Has anybody created a thing like that?
Good idea eh?


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## Captain Ahab (Jul 31, 2009)

I like it =D> =D>


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## bassboy1 (Jul 31, 2009)

Is this in an electric only lake? If so, do watch out, as that may not (probably not) be allowed, and could be considered a ticketable offense. No problem with the idea. Just an inexpensive form of a portable generator, just making the power by use of an alternator, instead of a generator (2 different animals entirely).


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## radiorob (Jul 31, 2009)

Never thought of that but I have contemplated making a "hillbilly mud motor" out of a weedeater. I've seen them done before and it doesn't seem hard to do. Some are as simple as taking the line spool off and adding a prop. Other ones I've seen made their own shafts and used angle grinder gear reduction units and made some pretty sweet backwaters motors.


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## Loggerhead Mike (Jul 31, 2009)

never done that but we did make a trolling motor out of an old ford starter. work'd like a hoss untill the insulation off the cables started dripping


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## thudpucker (Jul 31, 2009)

I had a large open 22' Cedar boat that collected a lot of rain. I made a 'cost reduced' bilge pump from an old Chevvy starter motor, a cable running down to a Washing machine pump.  

This Weed eater battery charger idea came from a time in Canada fishing. Miles and miles of nothing but nature. If something happend you might be rowing for a week before any help showed up.

I'm gonna have lunch with my favorite Mower shop guy today. I'll ask him about it. I think there must be some Motorcycle Alternators, maybe a small Jap car alternator....?
Those weed eater engines wont drive much 'effort' and he may have some answers for me.


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## pbw (Jul 31, 2009)

Why not some solar panel all day?


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## cyberflexx (Jul 31, 2009)

pbw said:


> Why not some solar panel all day?



Wont work like you think.. It would take weeks to charge the battery up enougfh to use it with a little solar panel @ 5watts. I had thought about the same thing and when I did the math, it just wouldnt work for my needs. Now if the battery were to sit over the winter, yes, this would be a good idea to keep a very slow charge on the battery to maintain it.


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## lckstckn2smknbrls (Jul 31, 2009)

IIRC I've seen pics of war torn Bosnia where they were using a water wheel in the river hooked to an alternator to charge batteries.


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## ben2go (Jul 31, 2009)

A friend and me used a 30cc weedeater motor coupled dirrectly to a GM 1 wire alt.Worked well,but the alt will run thru bearings when it's constantly spinning at 7000 rpm.

This isn't ours but it's put together the same way.


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## thudpucker (Jul 31, 2009)

Ben, thats almost exactly what I was thinking. How'd it end up?
Did it charge a battery in an hour or so?
The reason the bearings went is the direct drive. Had you used a belt drive and geared it down the bearings would not have had so much vibration to deal with.
Good on ya bub!


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## ben2go (Jul 31, 2009)

thudpucker said:


> Ben, thats almost exactly what I was thinking. How'd it end up?
> Did it charge a battery in an hour or so?
> The reason the bearings went is the direct drive. Had you used a belt drive and geared it down the bearings would not have had so much vibration to deal with.
> Good on ya bub!



Correct.The bearings couldn't handle the rpms.A belt drive with 2 to 1 pulleys would have solved that issue.We had 14.2 volts.We never tried to charge deep cycles from a deep state of discharge.We ran four 6 volt golf cart batteries that powered a 2000 watt inverter.We would run the batteries down and then charge them with then genset.We usually had to leave it running.The alt we used was only an 80 amp GM one wire from Summit Racing.


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## ohm (Jul 31, 2009)

Get a 105 amp Ford alternator from the wrecking yard cheap


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## thudpucker (Aug 1, 2009)

thanks for the details Ben.
I'll have a small car battery for my drop down. I'll know more after I get some experience.
I looked for pully's etc that would connect to my 55cc weedeater. Maybe that's too much engine. 
It ran all morning long on that little bit of gas it holds. About a pint. Four hours should re-charge any battery.
I should be able to come up with a Feather light somewhere, and a smaller Alternator than a full sized Chevy.
You guys went right to the front of the line with your invention.


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## thudpucker (Aug 1, 2009)

ohm said:


> Get a 105 amp Ford alternator from the wrecking yard cheap



Well, c'mon now and post a photo of your 'Cost reduced' portable battery charger.
I'm working at becoming a recognized talent in the art of copy and plagiarizing. 8)


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## CarlF (Aug 1, 2009)

High revs is the problem with adapting a weedeater to most other uses. They are made to run at 6000-9000 RPMs.
Guys who build mudmotors out of them have to come up with some sort of gear reduction or the props just slip like hell. It can be done but seems like a lot of work to me.
Definately will need a reduction for an alternator as well.


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## ben2go (Aug 1, 2009)

CarlF said:


> High revs is the problem with adapting a weedeater to most other uses. They are made to run at 6000-9000 RPMs.
> Guys who build mudmotors out of them have to come up with some sort of gear reduction or the props just slip like hell. It can be done but seems like a lot of work to me.
> Definately will need a reduction for an alternator as well.



True,but a belt drive can be used for an genset.Mud motors need a direct drive or some form of clutching mechanism.Here is an thread on weedeater mud motors.
https://www.boatdesign.net/forums/diy-marinizing/weed-eater-engine-conversion-1681.html


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