PMA Permanent Magnet Alternator Generator 6.5 hp Engine Battery Charger This is a 175 amp (rated) permanent magnet alternator being powered by a 6.5 hp Lifan horizontal shaft engine purchased at Harbor Freight. This is the first iteration and I believe the pulley on the engine could be larger which would allow the engine to be almost at an idle and still put out well over 25 amps. In the current configuration, it outputs about 30 amps at only partial throttle. At full throttle it pegs the 50 amp meter, so I have no idea what it is really putting into the battery at the full 3600 rpm that the engine is capable of. The initial problem with the setup was that the PMA came with a pulley size of about 2 3/4″ and the engine was spinning it WAY too fast. Another video contributor on YouTube, STUCKINWAWA, advised me that a 7″ pulley on the PMA would work better and he was right. The big problem with that is that the PMA has a 17mm shaft and I didn’t own a 17mm drill to open up the 7″ pulley bore. A little time on the lathe with a boring bar and the problem was solved. I also had to reduce the thickness of the cast-iron pulley on the lathe. This setup should charge a battery in short order once the pulley sizes are maximized for the engine horsepower. I plan to run everything on my boat dock with this unit, a battery, and a 6000 watt inverter to provide plenty of AC. The neodymium magnets in the alternator have a cogging effect and you may have to make a drive-belt release to get …
22. February 2010 at 6:11 am
well it makes more sense to me to make it charge as fast as you can, might as well get full use out of what you have, just my opinion.
23. February 2010 at 10:57 pm
depending on how safely you can charge batteries pretty quick you could set up a nice garage with the things for all power needs more batteries a good inverter
19. April 2010 at 4:11 am
lol i have that same mother for my go kart (from habor fraght)
2. May 2010 at 2:09 am
Is that 21 v i see ? Wow.
2. May 2010 at 2:16 am
Sorry i meant over 20 + amps , Can you regulate the charge to the batteries with this type of set up , without the gm type alt ? Nice set up …..
2. May 2010 at 5:25 am
It was almost 40 amps going into a battery that was already fully charged! The problem I had was the PMA was putting out about 17 volts with no way to regulate it other than making the engine run much slower, or adding a whole bank of batteries to create a bigger load. Thanks for looking.
3. May 2010 at 1:28 am
Use an old Moped motor for better results. 2stroke 12,000 rpm and you can gear it how ever you need to. + it uses less fuel.
6. May 2010 at 2:41 am
Couldn’t you get an Alternator with a regulator built in?
6. May 2010 at 4:02 am
@bigchad007
Actually, I don’t think there are any PMA’s with internal regulators, at least there weren’t when I put this system together. The typical automobile alternator regulates output by reducing the voltage to the rotor, which reduces the magnetism acting on the field coils. In a PMA, the magnets on the rotor are always on and working at maximum.
28. May 2010 at 12:14 am
@aaronanalog Nope, two strokes are very inefficient compared to overhead valve four strokes.
9. June 2010 at 7:50 pm
love the rev counter were did you get it great kit I love back yard
engineering and tinkering love the video thanks for sharing it with us
andy
18. June 2010 at 3:39 pm
it would be better to have an external regulator, so if anything fails, you don’t have to replace the entire thing
21. June 2010 at 2:06 pm
I invented a breakthrough energy source which violates the law of energy conservation. I have a PROOF that there are electrodynamic phenomena which violate the law of energy conservation. I am looking for $30 000 for a prototype and for $3M for patents. Making a 15 kW generator will cost $1200 in mass production, value of the energy produced yearly about $10 000.
H. Tomasz Grzybowski
tel. +48-512-933-540
23. June 2010 at 10:51 pm
Wow, some commenters have no clue about under/overdrive pulleys. The 12,000 RPM moped motor suggestion was funny though. Just apply the same principles of an auto transmission shifting from low to high gear (overdrive) and you’ll understand. Maximum output at the lowest engine speed possible is the goal. No point in constantly over buzzing the engine unnecessarily for sustained periods, not to mention, it burns more fuel and engine longevity.
24. June 2010 at 2:10 am
@TheWindMillMan In case I didn’t answer this for you before, I got the little Tiny Tach at a local lawnmower/outdoor equipment place. They usually have 2 or 3 different styles, but they are a bit pricey (around $35). I think Briggs & Stratton makes one that is cheaper. I was kind of hoping Harbor Freight would carry some small electronic tachs for about $8, but that hasn’t happened yet.
29. June 2010 at 5:46 am
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1. July 2010 at 5:47 am
i just want to built a device who takes iput from 11 hp lombardini engine to recharge the battery..which i want to use in my atv vehicle for campaign purpose in picnic…plz give some details of battery and current produce ….actullay i want to use the power of battery to recharge battery…lightning..other application…..
9. July 2010 at 9:47 am
@wiredforstereo that’s why you can get 85 horse power from a 250cc Rotax
15. July 2010 at 4:57 pm
@jacktheripped Yup, powerful, great power to weight ratio, but still less efficient.
23. July 2010 at 9:59 am
i will like to buy one
31. July 2010 at 7:53 pm
put a smaller pulley on the alternator, that will give it some boost
10. August 2010 at 7:15 am
You don’t think putting 50 amps into a dead battery will destroy it? Batteries are not like gas tanks or water balloons… it’s not a matter of “filling up” as quickly as possible. It’s a chemical oxidation/reduction process with fundamental physical limits as to how fast they can be charged. Over doing it, which you clearly are attempting to do, will likely cause it to overheat dramatically. This in turn will almost assuredly result in a nasty explosion, sending acid everywhere.
21. August 2010 at 10:53 pm
I invented a breakthrough energy source which violates the law of energy conservation. I have a PROOF that there are electrodynamic phenomena which violate the law of energy conservation. Making a 6 kW generator will cost $1200, value of the energy produced yearly $5400, zero operating costs. I am looking for $300 000 for a prototype and for $3M for patents.
H. Tomasz Grzybowski
tel. +48-512-933-540
3. September 2010 at 2:03 am
@dougaustintx if i want to move alternater with a 3000 rpm motor , so which motor will u suggest me,, and if i attach a gearbox then ?? please reply me,
3. September 2010 at 2:13 am
@zoni3 I don’t know what kind of alternator you are planning to use, but I can tell you that most alternators will take a lot of horsepower once the load is applied. I would not go with less than a 6 hp engine. If you live near a Harbor Freight store or can mailorder one, they put their 6 hp engines on sale for about $90 fairly often. Run the engine as slowly as you can to conserve gas. I would not run a gearbox due to the complexity and lack of long-term reliability.