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Multi-Use Generator!

Discussion in 'Off Grid Living' started by Too Country, Jul 19, 2016.

  1. Too Country

    Too Country Jack of all trades and master of none.

    For a friend we built a motorized bike. Then had the crazy idea of turning it into a power generator by first building a frame to lock the bike in with the rear wheel up. Then mounting auto alternators to it so that when the bike is mounted the drive chain engages sprockets to spin the alternators. We were able to have 4 alternators and the little two cycle motor was able to power them with no issues. The motor itself gets almost 160 MPG and sells for about $150. So you can use it to run around and then charge your batteries with it!


    Sorry I dont have any pics of the entire rig, gotta purchase another camera!
  2. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Last edited: Jul 20, 2016
    Dont, Altoidfishfins and Ganado like this.
  3. Altoidfishfins

    Altoidfishfins Monkey++

    Power 4 alternators? Harkens back to the old saying, "If it sounds too good to be true..."
  4. Too Country

    Too Country Jack of all trades and master of none.

    It should be said that I haven't been back to test the efficiency of the alternators, charge times and so on. The motor does run the alternators and that's not to say what level of efficiency. Clearly I would not expect even 25% per and would currently be a guess. But its a low tech solution for a slow charge option. When I talk about efficiency I am speaking of charge output of the alternator. By changing tooth count or pulley size at the alternator you can get variations in RPM and input power required. Higher output efficiency requires greater power input and higher RPM's. I considered the idea crazy, he wanted to try and had the parts. We achieved power output and you could utilize the charge. I consider that some sort of success.

    Now with all this said I will get pics and video. I will also get more definitive numbers. I intentionally made no claim to power output efficiency and so on as I just don't have all the numbers. Gotta love the internet. People are much happier as a rule to jump on a conclusion rather than take the time to question and consider whats actually been said. I am many things gentlemen but a liar is not one of them.

    Oh and it should be pointed out that this set up would be able to produce much higher output with only one alternator. The motor is around 3 hp and would give fairly good performance. We set it up the way we did because that's what he wanted. With a single alternator you output efficiency would break above the mid line quickly. Just food for thought.
    Last edited by a moderator: Jul 20, 2016
  5. BTPost

    BTPost Old Fart Snow Monkey Moderator

    Do the Math.... 3 HP = 2.2Kw not including conversion Losses.... at 12Vdc that is about 180 Amps.... Pretty hard to get that kind of power out of an Auto Alternator, for any length of time... You would end up with a puddle of Melted Aluminum/Copper Slag....
  6. Too Country

    Too Country Jack of all trades and master of none.

    I have run 1 Alternator on one of these motors and it worked reasonably well and got about 55% output from the alternator which is normal. Alternators should only run at full capacity in short bursts. A normal automotive alternator at idle makes about 50 amps and will charge a battery. I remember when 80 amps was considered high voltage and now on modern cars you see about 160 amps.

    For example the AC Delco part number 13501721 Alternator makes 150 amps @ max and about 50 amps at idle. Jump a car off with this alternator and a dead battery. let it sit and Idle and it will charge the battery.
    Last edited: Jul 20, 2016
  7. Too Country

    Too Country Jack of all trades and master of none.

    I think there is a way to settle this we can both agree to. I will attach the alternator listed above to one of these motors. Connect it to a drained battery and start it up. Video the entire thing until the battery is at full charge, monitor RPM and temps and post it to youtube for everyone to see. And if your satisfied with the video and what I have demonstrated on the front end. I will send the entire rig to you for you to test on video until failure. Now I don't know how I could be more fair than that so what do you say?
  8. oil pan 4

    oil pan 4 Monkey+

    Lead acid batteries usually only want to charge at about a 1.5C rate max.
    For bulk absorption they will only charge at about a 1C rate.
    So unless you have a battery that is unusually large its not much of a test.
  9. Too Country

    Too Country Jack of all trades and master of none.

    Lol, well it seams to me to the test is on point. As this is meant to be something you can use in a pinch that will work. I have not made any grandiose claims about what this rig will do. I feel as though I have been called a liar on a polite, implied basis so I wish to prove my position. Now, once the unit is sent he can test as he pleases within a certain fairness standard. I don't know what else one would expect of such a situation.
  10. oil pan 4

    oil pan 4 Monkey+

    This is what I am building and I am going to try and destroy the alternators:
    Home made generator, mig/stick/tig welder, 48v battery charger, engine starter | Survival Monkey Forums
    Using a 25 horsepower engine and doubling the exciter field voltage. I'm going to break something.
    The motor bike engine may not produce enough horse power to be able to damage the alternator. Plus the alternators are designed so that its difficult for them to burn up (this is why I an using 24v for field excitation). With the alternator in cool air out side a hot engine bay it should be very difficult to burn up an alternator, this is why I am counting on. The magnet wire used in the stator and exciter windings of an alternator is rated for 200'C. I have wired up a 130 amp exciter to 12v battery and let it sit on a bench and cook, while I watched it with my FLIR, it barely made it to 100'C after 10 minutes.
  11. Too Country

    Too Country Jack of all trades and master of none.

    Very nice, I may have some of the parts you need. I have several large pure sine wave inverters and more stuff than I can keep up with...
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