DIY DC Generator: charge batteries off grid

Comments · 1K

• RE

  @regularpit1508 · 3 years ago

  I have that exact treadmill sitting in a corner watching as everyone walks past that room like it doesn't exist.

  11

• BO

  @boblatkey7160 · 3 years ago

  I've lived off grid for 24 years and I did this with an engine and a vehicle alternator that I bought from a rebuild shop and charged batteries for my household. It worked great for about three years!

  15

• MA

  @magic.marmot · 3 years ago

  25 minutes in, as you're tightening the belt, watching the standing waves in the belt sort of "tune in" as you tighten it is lovely.

  15

• SC

  @ScottPlude · 3 years ago

  I did a project similar to this several years ago. A harbor freight 5hp engine connected to a 60 amp auto alternator and a standard car battery (optima yellow top) to keep things simple. It was intended to allow ham radio operation in a grid down scenario. I welded a small frame with casters and it worked very well. I still have it in my garage. Works well when I see a dead car battery as well. Roll it over to the vehicle, fire it up and in just a few minute I have a healthy battery again. I used large anderson connectors with battery clamps to make it modular and useful for many scenarios.<br><br>Your scenario is a bit beefier for powering an entire home but the concepts are similar. Great minds think alike!

  131

• D_

  @d_ward4871 · 3 years ago

  The amount of great input you can get from a productive comment section is amazing

  8

• P_

  @P_RO_ · 3 years ago

  Shades of the old Jeremy Fielding 😎 A few thing here. This type of engine is designed to run against it&apos;s governor at full RPM&apos;s or just slightly less under a full load. &quot;Bogging&quot; slower loses HP and tells you the engine is producing all that it can and this is your load limit. Changing pulley sizes will not get you any more power, use that to achieve the load RPM you want. Have the belt loose for starting, and use a smooth-faced idler pulley from a junk car to tighten. The spring tension on those is too high for a single belt, but a hand-adjusted threaded adjuster of some sort should be easy. The engine and &apos;generator&apos; need to be mounted as solidly as possible; anything that bends or flexes will amplify vibrations. Use rubber mounts or feet under the whole assembly if vibrations are a problem, remembering that vibrating wires break quickly so secure those well.<br><br>The electronics are on you as you know that better than I ever will. I ❤ DIY and repurposing, especially when the parts can be had for free. I only subb 2 YT channels on this topic and yours is one: Straight shooting, no BS, intelligent, and everything covered in depth but using language anyone with an interest can easily understand.

  5

• ST

  @stevennope8864 · 3 years ago

  Might want to re-size your pulleys for increased torque output. Obviously you&apos;ll lose top end speed, but you might be able to get a nicer middle ground, where the engine will work for the application. The engine should be able to run without stalling with some minor adjustment of the ratios. Also, might be able to sacrifice a lawn mower deck for the spring tensioner pulley. Or buy one at a hardware store. That might help reduce some of the vibrations, particularly when loading and unloading the motor. Excellent work as always. The only problem with adjusting the pulleys is that it won&apos;t be as efficient for operating at the lower level voltage loads.

  85

• RE

  @reyes2009 · 3 years ago

  David, yoy should try a lawn mower motor with an alternator. That would be a much more potent mix. Btw, the rubber between the motor and the frame is contributing to the e vibration.

  9

• MA

  @maxring837 · 3 years ago

  We made these things in the 90s to charge off grid systems and quickly realised that an engine power curve is not linear. If you consult the engines specs they often give a power curve relative to rpm then adjust your Pulley ratio to suit. You will also find you will need a much larger fuel tank and frequent oil changes and in about two weeks of running a new engine.

  3

• AP

  @apollo280zx · 3 years ago

  Quick tip- treadmill motor shafts are typically LH threads to prevent the flywheel from coming off during operation. Yours is no exception as you can see the LH threads at <a href="https://www.youtube.com/watch?v=DaF6n-9RVT4&amp;t=138">2:18</a>. So to remove it you&apos;d need to turn it clockwise if looking at the flywheel head on.

  47

• MI

  @michaellane4762 · 3 years ago

  I like that you are trying to design charging systems for people who want battery back-up but can&apos;t use solar. Carry on you will get it right. Mike

  5

• RI

  @richardbilous5338 · 3 years ago

  I miss hanging with ya David! My smart buddy! Thanks for watching me all those years! I cherish all the days you tought me things! I still think you should be a teacher! You tought me things faster then anyone in this world could!

  1