Home built generator battery charger using Permanent Magnet Alternator 6.5 hp engine

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 the engine started, then tighten the belt.

Category:

Science & Technology

Tags:

• PMA
• permanent
• magnet
• alternator
• engine
• battery
• charger
• homebuilt
• homemade

[dougaustintx]

The idea is to have STORED energy for use when you need it. It's kind of hard to store AC, but batteries do just fine with DC.

[Redneckology]

Nice! Good way to recycle a road sign too.

[dougaustintx]

@Redneckology Hehe... yeah it is. You have a sharp eye. I was trying to keep the base as light as possible, and the "recycled" road sign has some good back bracing built into the extrusion.

[zoni3]

@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,

[dougaustintx]

@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.

[TheWindMillMan]

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

[dougaustintx]

@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.

[wwweshop4youcom]

use hho as power for generator, i think it can also work on hho only, but if it is used as second fuel source it is good also

[simonspaz]

It's always best to run it on part throttle, not so much tickover/idle. At idle the piston rings don't have enough compression to make a full seal and eventually this leads to glazing of the bore and that in itself gives poor compression and will mean lower output.

I used to get this on old police cars when they had excessive idling. The only option was the re-hone the cylinders and put in new piston rings.

[callmeshane303]

Nice set up - bit too springy and flexible for my liking - the parts have a tendency to fatigue, crack and break.

I myself would be inclined to spin the alternator at it's maximum RPM, at the motors maximum RPM and set up gearing to that effect.

I'd also fit in a lever with a spring to release belt tension when starting and to allow the belt and pulley system to act as the infrequently used clutch.

[steveBB30]

@zoni3 Electrical power in watts = Current *voltage

756watt=1hp

6 hp motor outputs 4536 W on the shaft

if that were transferred to the alternator and converted at 100% efficiency to 14Volts that would be 324 Amp

efficiencies of 90%*95%= 86% more likely. That's still 277 Amp!

Get the torque curve for engine, and find RPM for max torque. Run engine at that speed for best Brake specific fuel consumption. Use pulley drive to alter alternator speed. Will need sufficient power. Torque*RPS=power

[star2067]

A car alternator is already AC (when u remove the diode and the regulator) then why turn with permanent magnets (provides the DC) and DC and spend a sine inverter in order to have AC??

alternator = current alternative. So the alternateur it already in AC ! and without the regulator can give u at 9000rpm 56volt 120A of AC multiply with 2 alternator you got 112 volt and 240A ... Just need AC capacitor in order to smooth the AC sine.

[Rayxl1]

Mine's going OK now I've given it a 2 to 1 reduction from engine to alternator.

[han050]

ive got one of my one i bilt it my self and i have a 100 A alternator and it works great

i have not put up pictures or films on it on the web

[pixar5]

ive got a pma from windbluepower and use it as a bike generator spinning it with a bike and a belt and found the belt has to be tight which mine isnt that tight but yea can light lightbulbs and charge small batterys within time its just a fun project to learn about electricity

[whackitov]

let me know if ive got this wrong... 1hp =750 watts right?

so 6.5 hp must = 4875 watts.

so you are using 4875 watts of power........to charge a battery?