Building a 48v Off Grid Generator: Part 2 - Got it figured out!!!!

Comments · 218

• ON

  @Only1Shadow · 3 years ago

  No modifications to the alternators were needed - mount the 2nd alternator so it is completely electricly isolated from the frame, connect the output of the 1st alt to the ground of alt #2 and the output of 2 is now 48v. Running  both fields from one regulator is asking for a meltdown

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• DE

  @debohannan4315 · 3 years ago

  We use to buy those 10si GM &nbsp;one wire Alternators for our tractors and trucks all we needed to do is replace the regulators for 6 volt ,12 volt or 24 volt it was simple and cheap in fact the <br>Alternators were only $19.95 from Auto Zone . Some guys even ran 12 volts to the brushes and got 90 to 110 volts out to run flood lights . so those were great to have on the shelf at the farm.

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• DO

  @DoctoreE644 · 3 years ago

  I guess I am a little late, but maybe if I can clarify a couple of things about your alternators (and most others). The little black rectifier that is attached to the main rectifier bank and the stator feeds 24 volts to the internal voltage regulator, and through the electronics inside the regulator, it varies the voltage and amperage to the rotor, and increases or decreases the output from the alternator. Now, the main rectifier bank is conveniently an isolated rectifier, and can be unbolted &nbsp;and attached externally anywhere. In the alternator, the negative side is bolted to the alternator case for ground, and the positive side is held into the case by way of the output terminal and insulators. If you look in between the two sides, you will see the rectifying diodes with the tabs running out to the 3 studs the stator wires attached to. Actually, you probably could have used one or both of the rectifier banks in place of the store bought rectifier you bought, and mounted them on the post. Now, I don&apos;t know how long the voltage regulator will last, because it is providing double the amperage to the rotors. Particularly at 48 volts. Your jury rig works well, apparently, but another way around it is to run external wires &nbsp;out of both of them to feed both rotors from one source. There are many electronic voltage regulators that will work on 48 volts, at very reasonable prices) available on the market that should be able to supply the max amperage draw of both rotors (check the draw with an amp guage, on your multimeter if it can take 10 amps or better, and then double that to get max amp draw). <br>I noticed a couple of posts that showed concern for synchronization of the alternators, because of phase issues. A simple work around is to use a timing belt, and corresponding timing pullies for the motor and the alternators. You would have to make corresponding marks on the stators and rotors (a white dot of paint would work) so both fingers of the rotors correspond to the same place on the stator windings. Voila, synchronized alternators! <br><br>I&apos;ve got 50+ years experience rebuilding alternators (and starters), and have done many hit and miss experiments over the years (ex., solenoid motors from car starter solenoids), and have learned a lot from playing around with stuff. So, we are birds of a feather, and I just turned my curiosity into a business. If you have any further questions, let me know. I love where you are heading with this. Oh - on other comments about RPM, yes, most alternators run at around 5000 RPM for the maximum output. Increasing your engine pulley size will speed up those alternators. Which, by the way, originally came out in the late 60&apos;s or early 70&apos;s, so the design has been around for a long time. Apparently the builders rewound the stators and increased the rotor magnetism to increase the output. Modern automotive alternators are 120 and 135 amps now, &nbsp;and about ½ the size of those. I have no idea what the no-load voltage is on one of those!!

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• TA

  @tallbrian100 · 3 years ago (edited)

  All you needed to do was to electrically isolate one the alts from the mount then you could wire them in series.

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• FO

  @Fox_Nakamori · 3 years ago

  i watched the first one and right as that one wrapped up this one popped up, clever twist on external regulation and conversion, glad to see it worked out for you

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• SO

  @solarandwindinsouthtexasda1473 · 3 years ago

  You can get a 12v alternator and &nbsp;get 75 to 120 v because that is how you BILT a welder out of a alternator

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• TH

  @theheathkitshop2424 · 3 years ago

  Great build! That being said, I sure as hoping to see more than 35A coming out of that pair of alternators. Squirting that much current into a battery bank the size of yours is like pissing into the wind. I was thinking 100ish or about. &nbsp;Although not as much fun, a used 48V forklift battery charger running on a LARGE generator would get those beefy lead-acid guys a bubbling.

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• CH

  @chrisfrombrisbane · 3 years ago

  Thank you for your great work. Please do a follow up video. Building on your current knowledge and feedback from viewers. To summarise and suggest a simplified build and supply model numbers of components. As we non electrical people are not quite getting it. thanks and I am from Australia.

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• JC

  @jchoneandonly · 3 years ago

  You should do an instructibles page for these projects

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• MR

  @MrVeryCranky · 3 years ago

  suitablely heavy wire would allow more current. The wire you connected to the windings should be rated at least 63 amps per phase.

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• JE

  @JerrySmay · 2 years ago (edited)

  I just stumbled across your first video of this project and got instantly enthralled. I am 73 and have spent my life on diy projects like this one. &nbsp;And I think the name you chose for the channel is awesome. It describes my whole life.<br>David Poz did a similar project on his channel &quot;DavidPoz&quot; only he used a single alternator, removed the regulator and ran the output into a solar charge controller. <br>Both your project and his were very interesting and enjoyable but both were too expensive and too much work for me.<br>I have a similar project in mind in my budding solar journey. &nbsp;I already have a 120v 3000w generator but I don&apos;t want to spend $500 bucks on a 48v charger. <br>So, I &nbsp;am going to &quot;TRY&quot; running the output 120v ac out of that through a 200amp full bridge rectifier (Amazon $23), add a $2 capacitor to smooth out the rectified dc and feed that into a cheap 48v solar charge controller. Run the generator on propane or better yet natural gas and not have to deal with gasoline at all. <br>Should work, maybe it won&apos;t. &nbsp;&quot;Trial and error&quot; .

• MA

  @MattLesak · 3 years ago

  Very cool and nice to see it working!

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