http://www.webpal.org/webpal/b_recovery/3_...r/generator.htm

Dont know if yall have seen this or not. It might be useful for those who have the parts or may be on a tight budget.

Hell that is a good idea I have 3 lawnmowers that the decks are worn out on but the engines are top notch. Now I am not getting rid of them!

At first glance, one may think 12v battery $60, 1500 watt inverter $100, and pulleys, brakets, junkyard altenator, cables, and belt, the overall cost would be around $20. The same output new 2 cycle would be around the same cost.

There is a distinct advantage to this setup though. Where a traditional genset only operates when the motor is running, the lawnmower battery inverter setup will work when the motor is off. The low voltage alarm on the inverter will tell you when you need to charge the battery with the lawnmower motor.

Yes, Running a lawnmower costs a lot less in fuels than a car engine.

Not bad, not bad at all.

Tj

awesome, Ill have to look into doing that!

That would appear to be a very inefficient method of generating 120v power. There is another way, as alternators produce about 110v, just at variable frequencies. Setting the lawnmower to the proper speed to regulate the frequency would make this a better system.

Here's why this is inefficient. The alternator generates AC. This is converted into DC via the diode pack inside. The new DC voltage is sent to a battery, and then to an inverter to convert back to AC. At most, these devices have about 20-30% efficiency. Generating an AC voltage directly from the alternator would be much more efficient. However, if one's main goal was to charge a battery for a car, or some other equipment, this could be a good tool for that.

A good point, Pepper although I might argue with the percentrages quoted.

Lawnmower engine govenors are not good enough to maintain anywhere near 60cycles in most cases. If one wants to REALLY get into the eff. discussion, consider how much less fuel a water cooled engine uses - or a diesel.

In any event, the "mower generator" is a viable choice that can be assembled on the cheap and make use of an engine you have laying around. Great machine to charge your car battery too!

The percentages were something just pulled out of thin air, please correct me if you have a better idea, I just used those to give a rough idea of the losses involved. About the frequency, you're right. But, that would be a moot point with many electrical appliances. Heating elements, drills, saws, etc. might not be too badly affected by the frequency being off, as long as the motors were used in moderation. And, using it only to charge batteries would work just fine.

Anything that I planned on using AC for, I would use a regular generator.

I'm intersted in it mainly because its cheap, I have the mower and the GM alternator already. Just think of the places it will go with bigger wheels on it. Also, in a SHTF scenario where driving isnt an option, you could keep an extra mower, minus the engine, to use as a pushcart for all of your gear.

Or a tactical wheelbarrow.

Wonder how long before he shows up with it and his silenced .22?

Actually I think that IS the point. If you have the money for a generator, buy one. Odds are though when you really need one and don't have one or yours just broke, your local Home Depot will be sold out.

Tj

Hey, leave TJ alone!!!

Jay

I don't see a .22 in there.

Jay

great idea. now i have to keep that old grass cutter........

Really cool idea. Now,what are the car batteries for,or are they charging them?
Anyway,I have 2 mowers sitting out by the barn tha tI was gonna througfh away,guess not now.
Thanks for bringing this to our attention! Nothing like American ingenuity (engineuity??)

This post has been edited by Coondog: November 5th 2005 5:51 PM

The batteries serve several puposes. One, obviously, is storage so you can operate small loads without starting the engine. Second, most of the newer alternators need a battery to energize the field and cause the unit to start producing power. Third, and this is very important, the DC output froma n alternator is NOT pure DC - it is a series of pulses. SOme of those pulses are a good bit higher in voltage than what you want, which is about 13.8 VDC. A storage battery, in this case, acts as a "filter" integrating those pulses and VASTLY improving voltage regulation. Result is nice clean DC; just what we need!!

I would suggest the older GM alternators like the ones pictured. They are cheap to buy - $5.00 or so, very easy to repair and cheap to do so. No special tools required, either. I will even doa tutorial on fixing the things if you like! They are more durable than the newer ones and a boatload cheaper. The 100+amp ones often used now require a good bit more horsepower so may exceed the mower engine's reasonable output.

This thing can also serve as a great "jumper cart" for the family vehicles too!

Ahhhh,I see. Thanks for showing that to me.