DIY DC Generator: charge batteries off grid

[@ScottPlude]

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. Your scenario is a bit beefier for powering an entire home but the concepts are similar. Great minds think alike!

[@alasdair4161]

Interesting, I also built something very similar back in the 80's using a tiny 1.5hp side valve Qualcast Suffolk motor and the smallest alternator I could find, I made my own multi chamber muffler and built a minimal sized lightweight moly frame then added sound absorbing panels to deaden noise. Originally intended as a camping generator (also the reason for quietening it as much as possible) I still use it as an emergency power source to this day. The alternator self excites so I also squeezed in a small inverter which can run lights and small appliances and it runs all night on a couple of litres of fuel.. It's small, lightweight and very easy to start and is also very quiet, the antique motor has long stroke for it's size and just chugs away quietly as dependable as can be. Variants of this can make great project builds for anyone. About fifteen years back I stripped it down, sand blasted and powder coated the whole thing and now it looks better than ever, and it should last almost forever. Cheers.

[@Banzai1338]

If you put a stage 2 or 3 kit on the predator you would be able to get about 15 to 17 horsepower no problem

[@BLAZE13011]

Ive thought of doing the exact same thing still haven't gotten around to it yet but at some point I will

[@hodwooker5584]

I built a 13.5 vid version of this with a Chevy one wire alternator. I direct coupled the alternator and engine(4.5 hp) with a love joy type coupler. The coupler I used came from epicenter’s website the alternator half of the coupler needs to have left hand threads. You could at that time also get parts for belt driven alternators from them. I hope they are still around. I can get 25 amps out and it takes about a half hour to recharge my trolling motor battery’s. So fish all morning, eat lunch and charge battery’s.

[@hodwooker5584]

(4.5 hp)

[@magic.marmot]

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.

[@stevennope8864]

Might want to re-size your pulleys for increased torque output. Obviously you'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't be as efficient for operating at the lower level voltage loads.

[@stevennope8864]

The pulley on the motor would be easier to adjust, lol. Maybe just a 75% reduction in outside diameter? You might need to play with it a little bit. It will be easier to go bigger than smaller, because you will start causing belt slipping if you go to small, but that would require redoing your welds. If you go that route, might want to weld a quick change setup to the motor, so you can easily adjust depending on circumstances. Could also do dual pulleys on each shaft, with different sized pulleys for each load. Then you can switch the belt to the corresponding pulley set.

[@carrollmcpherson4530]

This right here is where I would start unless you wanted to buy a larger engine all along! 3 HP aught to get you a lot closer to 1800 Watts than bogging down at 900w.I am guessing that gas engine was meant to make its power at around 3600 rpm and the dc electric motor was meant to be run at around 1700-1800rpm. So your gas engine pulley may need to be half the size of the elec. motor (generator) pulley. This would at least be a good starting point. An even lower ratio (say somewhere around 2.3 to 1 instead of 2 to 1) might be better to ensure you don't bog down the little one lung china bomb creating high head temps and hot valves.

[@bretk7916]

Steven Nope, larger pulley on the engine will increase your torque and increase RPMs on the motor/generator

[@troy3456789]

@@bretk7916 He needs *just* needs to increase the pulley size on the now DC generator, at least 1.5 times bigger. It will slow as a result, and the engine will be able to turn it easier because it will have more leverage on it to do so. I think a chain and sprockets would be better, last longer. His engine flywheel is desperately calling for a clutch to be able to engage or disengage

[@Steve25g]

@@bretk7916 bigger pulley size on motor reduces torque. You need a smaller pulley on engine, or a bigger on the dc motor

[@boblatkey7160]

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!

[@LitheInLitotes]

This is really valuable and I hope you follow up with a bigger engine. As you know, the idiots out there selling 48v DC generators want to rob people for 3K. One guy tried with alternators but failed. A treadmill motor is plentiful and it was genius to use the charge controller.

[@DavidPozEnergy]

Thanks for your comment. I'd like to try again too with the bigger motor.

[@Trialnerror]

Hey, I got it figured out....eventually :)

[@johgude5045]

@@DavidPozEnergy I can recommend the QSMOTOR 120 . Should fit your project well

[@d_ward4871]

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

[@apollo280zx]

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 2:18. So to remove it you'd need to turn it clockwise if looking at the flywheel head on.

[@schoen88ss]

Hope he reads his comments. He put the whole thing together spinning the flywheel the wrong direction. Bad things will definitely happen if the treadmill windings fail or are overloaded.

[@LITTLEEXPERIMENTCHANNEL1]

Thought this, you got there before me right at the top of the comments. Bravo!

[@Capoe3]

Commenting for David to see.

[@leopoldpoppenberger8692]

@@Capoe3 also mount your electronics separately =no vibration

[@horacepinker6578]

I remove the plastic fan at back of motor put the exposed shaft in the vice so cant spin and unscrew them . Like you mentioned its a reverse thread. Can use oil strap wrench or plumbers wrench to get good grip. Worst case scenario grind two flats onto opposite sides of the small pulley and put a shifter on it and smack it with a hammer to loosen it. ( some have locktite)

[@alainmcin]

Hi David, I enjoyed watching your project.... I did something different, I took 120 volts output from my house generator, connected to a full wave bridge rectifier (1000V, 100A)...connected a capacitor(1000 microF, 450 volts to the output of the bridge, and fed that to the solar controller....because my controller is limited to 150V max. input, I adjusted the generator regulator to give 100 volts on the mains...since 100x 1.414= 141V.olt ( minus 2x diode voltage drop)...so I get around 140 volt max....this works quite well....I pushed 2.5 kw into the batteries....cheers

[@P_RO_]

Shades of the old Jeremy Fielding 😎 A few thing here. This type of engine is designed to run against it's governor at full RPM's or just slightly less under a full load. "Bogging" 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 'generator' 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. 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.

[@TabooRevolution13]

I use a 4HP tredmill motor on my bicycle generator. It's changed my life. Sometimes I'd now prefer to charge it than to use it. Great way to get fit off your internet addiction!

[@bencapobianco2045]

Love the project I’ve been collecting parts to build one for a while now. My suggestion is the treadmill motor is a permanent magnet motor so with the 48 volt batteries you could wire in a solenoid, some diodes and a switch to use the treadmill motor as a starter motor for the gas engine. I’ve had old tractors that use a DC motor as a starter then when the engine starts it works as a charging system. Old tech you should be able to adapt that concept pretty simply. Great job can’t wait to see version 2.0!!

[@foodstampz]

Interesting

[@chrisellingson123]

Very interesting project. I have a few suggestions. A centrifugal clutch would make starting easier. This will also allow you to warm up the engine at idle before loading the engine at running RPM. Unfortunately a typical MPPT type charger designed for Solar will 'hunt' for the max power levels this means the load on your motor (generator) and engine will vary/cycle. I think a work around for this is to limit the battery charging current setting to the below the max continuous power values of both the generator and engine for longevity and running effeciency. I would be temped to do an LPG conversion and implement a dual LPG/Biogas fuel system.

[@davidschwartz5127]

Running on LPG mean less output in power from the engine.

[@truck655am]

The Victron MPPT isn't cheap and you can set the Max charge current to that of the engine so it won't go over of the max capacity of the engine. Removing the charging cable ensamble enable it to restart the engine with a drill every time with no problems.

[@randacnam7321]

There are MPPT charge controllers that have wind and hydro modes and/or the ability to set a fixed input potential. Those would play better with a DC generator input.

[@stevec5000]

He already has a motor to use for starting. Just apply the battery voltage to the DC motor to start the engine.

[@jdcairncross3631]

@@stevec5000 exactly !

[@benssolarandbattery]

What an awesome project! I love how you reused all of the little parts and pieces from the treadmill. Thanks for sharing!

[@DavidPozEnergy]

Thanks Ben.

[@chrisdekock8864]

Yes, i love reusing old machines for projects! In 2017 i build a mini hay baler (4lb bricks) from an old washing machine!

[@richardbilous5338]

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!

[@noanyobiseniss7462]

Just change the circumference of the pully on the motor.

[@Chris...S]

Agreed, changing the gearing will allow for more torque

[@wg6215]

He needs to match the peak rpm for max hp plus he needs to know what rpm the electric motor runs at also then gear them accordingly

[@Sturgiselectric]

With the charge controller and the knowledge that the dc motor is 130volt. You can use the phone app and adjust the motor rpms until you show 130 volts in the app. A slightly larger pully on the motor may overcome the bog down when under load. Hope this helps.

[@paulpierce2051]

@@Sturgiselectric i think you want smaller on the engine and larger on the d/c motor? It seems to me the gas engine isn’t running at high enough RPM due to the load.

[@michaelmain1990]

Agreed pulley ratio would help alot

[@opennrgdotcom]

The Flywheels are left threaded. Fan pulls straight off with some effort. Pull the brushes out and the brush end off. Vise grips on the rotor shaft where the fan was. Turn the flywheel clockwise to loosen. Opposite of the Righty Tighty rule.

[@Teknopottu]

Great explanation.

[@flojotube]

DUDE .... where have you been all my life???? I have a dozen of these motors and GAVE UP trying to figure this crap out.... UNTIL NOW!!!! 🙏

[@NoelBarlau]

Really interesting to see the MPPT controller bogging down the tiny gas engine trying to maximize output wattage. I've had this same thought pattern regarding direct DC charging for my 48v Lifepo4 battery bank using a Lister CS 6hp single cylinder diesel, and this setup would come pretty close to ideal. The general rule is 2hp per 1000w output, so a 6hp diesel at maximum rated constant power should be able to output 3kW DC on a continuous basis. Still looking for the "perfect" solution for that equation. Great video, thanks very much for sharing, it was right up my mental alley.

[@DavidPozEnergy]

Lister engines are pretty darn cool. Thanks for sharing your thoughts.

[@carljacobs1287]

Actually the "MPPT" part of the MPPT seemed pretty poor. Surely it should've backed off the power drawn once it started going down, since isn't that the point of the fancy algorithm. You should alert the charge controller of this video, as I'm sure it should've been able to target around 1000W continuous.

[@petersack5074]

Wisconsin, air-cooled engines, are also ?....' cool ' too !

[@magic.marmot]

I love that you did this. I have a collection of treadmill motors that I've wanted to try something with, though my idea was more centered around a vertical axis wind turbine. I also wanted to try using them to propel a small electric vehicle (like a garden tractor), but the threaded-on flywheel doesn't work very well with reverse polarity. Under a heavy load, I suspect that the brushes will wear out sooner than expected. I haven't looked to see if the brushes are replaceable. For a low-cost backup unit, this is pretty stellar. Always amazed, good sir.

[@DavidPozEnergy]

A vertical wind turbine would be great.

[@keithcress1335]

Hi David. Fun project! Normally you get about 500W per horsepower of the IC engine. With smaller setups you should probably consider more like 400W/ per horsepower. 1,800W/400 = 4.5HP. So you're in the ball park. The ultimate limit is the engine speed. For you to get the engine's rated horsepower you must run it at the speed the rated hp is specified as. You need to change pulley size to a smaller one on the engine or a larger one on the generator. Also, the generator will only supply the watts it can at a particular speed. If you turn the generator slower it will automatically limit it's power output. By messing with the pulley diameters you can set the gear ratio to whatever generator power the engine can support at the engine's speed sweet spot. Ditch that generator pulley. Cut it off with a grinder. Grind a slot parallel to the gen shaft into the pulley. When you get down almost to the gen shaft it will likely slide right off. Doing this would let you keep the engine pulley as-is. As a guess I'd make the generator pulley the size required to have the generator turn 80% of the engine speed. These wing-it jobs with engines and loads (like a generator) often take iterations of drive ratios. With a little trial and error you should find a place where the engine can run without straining ~80% of it's rating all day.

[@rearspeaker6364]

1hp is equal to 746 watts.

[@LibertyDIY]

​@@rearspeaker6364Is that affected by the efficiency though so you only get 400-500 watts out of it?

[@IAMElectric369]

I love treadmill motors!! I have about 12 currently. I’ve got one that you have there too. That motor is a hoss! I built a generator using two of them, a single phase motor winding and some very strong magnets. Machine produces usable a/c and d/c at the same time. Would love to tell ya about it. Tip for you in your generator, Convert to a/c, clean it up then back to d/c. Microwave transformer. Step Up. Capacitor.

[@DavidPozEnergy]

Sounds good.

[@mattsadventureswithart5764]

Very interesting project, thank you. I'd like to give a little advice based on painful experience ref those little cutoff disks in your dremel. They do not take more than the tiniest lateral force before shattering into multiple sharp very high speed pieces. They really hurt and I'm very glad I was wearing proper safety goggles. Please, anyone who might read this, don't let them get the chance to explode like I did - only use them to cut, never to grind. AND as Norm always told viewers: wear safety glasses.

[@stephensmith6055]

Ive had some troubles with off brand and cheap disks also. my advice, the cheap tools are great, the cheap consumables, will cost you.

[@michaellane4762]

I like that you are trying to design charging systems for people who want battery back-up but can't use solar. Carry on you will get it right. Mike

[@donscottvansandt4139]

Awesome build! I think one problem with the hard start is the big harmonic balencer also could go with a smaller drive pully and a larger charge pully .I think that would work.

[@bretk7916]

Larger charge pulley would slow down RPMs and smaller motor pulley would sacrifice torque I think smaller charge pulley and larger motor pulley is what is needed

[@troynyholm232]

@@bretk7916 I believe you are incorrect...lower the RPMs will result in higher torque. Decrease the diameter of the drive pulley and increase the driven pulley will lower RPMs and increase torque.

[@reyes2009]

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.

[@rbartsch]

A direct drive is more efficient than a belt. Because of the low torque of the gasoline engine I suggest a gear/transmission ratio. You can also try to disable MPPT in the Victron charger or limit the charging current. If you connect the gasoline engine with a clutch on one end of the generator-shaft and a Diesel-engine with a clutch on the other end of the shaft you get a multi-fuel generator. 😉

[@ozimandia]

Is there a way to use a gear or another pulley to proper balance the system? I think that it will not only fix starter issue but as well get the maximum torque for the motor, there are calculators to help find the diamiter, but the real work will be in retrofit an reduction / balancing system in the setup.

[@chuckrussell6740]

Great job demonstrating eyeball engineering. Know that the Light of your being is a blessing to everyone on your journey. Shine on

[@dadbain]

Good effort David, now I'm looking forward to version two.

[@dominiclavu193]

Love your ingenuity and effort! Ways to recycle "old, useless" equipment...that's a way to save money. Kudos!

[@RevM]

Awesome idea David! I've got an old treadmill in my scrap pile that I had intended to haul off to the metal recycler ... I think I have a new purpose for it now!

[@DavidPozEnergy]

Cool. The motors are worth saving.

[@Teknopottu]

Metal recycler? I had to hunt down for months to buy a used treadmill motor to test with generators. Here in Finland there are fewer treadmills.

[@drevil4454]

Most eco friendly off drid projects. An engine for everything. Love it!!

[@landonferguson7282]

Maybe try setting a maximum charge current for the charge controller, to act as a governor for the engine, so the engine speed can stay within its correct range.

[@nunolourenco1532]

^THIS! I mean you need a governor, one way or another.

[@LibertyDIY]

Yeap that would have been an easy fix and stabilized the output

[@jacksin3323]

Key tip... those motors can make for great grinder motors. Ive saved 3 from the scrapyard, and made a beltgrinder, powerhammer, and wheel grinder.

[@dankelley9361]

Great idea, love your ingenuity! Would’ve like to see better where & why all the wires went, and exactly what functionality each device provided, like the charge controller & the choke.

[@galen__]

I recommend watching Robot Cantina from Episode 1 in 2020 for some videos on maximizing your Predator engine. I’m sure that you’ll max out the treadmill motor soon enough. Can’t wait to see this 👍 edit: They used the 212cc engine whereas yours is 79cc oops. I still think the 79cc can do at least 2x the 900W with a few additions like a torque converter, as others have said. These seem popular in gocart and minicycle circles for lighter weight options, but maybe hasn’t got the same attention the 212cc has or the bigger heavier others. Would be great to see an affordable 48V DIY generator using the 78cc or 212cc engines 👍

[@craighansen7594]

Changing the drive ratio will increase torque to the generator, how low of rpm will still produce good output? 3hp is a little small. Plus that engine does not start easily, you had to keep turning it over with the drill. Carb choke not working? It seemed hard to start even with no load.

[@kevkev5935]

This was such an awesome video. Not sure what I'm impressed more by. The ingenuity of the build, or how tight and clean your wiring was to the charge control and breakers.

[@DavidPozEnergy]

Thank you. Unfortunately, there was too much vibration. So, I'll be moving the charge controller off of this setup. It won't be as neat and tidy.

[@Ash1965..]

Hi I use a car alternator 120 amps I tried a 2.5 hp and had your problem so went to 6.5hp. You could also try changing pulleys like a small one on your motor

[@DavidPozEnergy]

Nice. Do you have any posts about your alternator project?

[@Ash1965..]

@@DavidPozEnergy no just look and learn yours covers a lot I didn’t know cheers

[@justincase5272]

Great approach, David! "I had fun. I learned a lot." Nothing finer!

[@Ghergyjubles]

Great video and idea.The amount of reuse from that treadmill is amazing. Could play around with pulley sizes, but you probably are limited by the motor itself. And maybe weld some cross bars on the bottom of the motor supports to try and keep vibration down.

[@jayw900]

The motor was fine, it's the engine that was a bit undersized. Could also be a pulley ratio as well.

[@raymondsmith1213]

Awesome build I'm gonna do it. Ive been making windmills with these, take the cooling fan off the back and vice grip the shaft to get pulley off, left hand thread ifI'm remembering right. You can also just turn the motor on then grind the flywheel down to size like that.

[@Vigo327]

Loved this. I have been curious about doing the exact same thing ever since i noticed a listing for a treadmill motor from Surplus Center. I can’t fault your design assumptions since an engine rated at 3hp should be able to max out an 1800w generator head, keyword “should”. But now that you have come this far, i REALLY hope you simply upsize to the Predator 212cc and try again. The engine bolt pattern to your frame may be the same, so i believe you would simply need a different drive pulley for a 3/4” engine shaft and you will be able to start it right back up and resume testing. I think the idea of putting a 6-8hp engine in front of a

[@DavidPozEnergy]

Thanks for such a great comment and information. Yes, multiple MPPT charge controllers can feed the same battery, at the same time, with different sources on each charge controller. This was one of my driving forces for this design. The MPPT charge controller can be set up to the same charging profile as my other solar MPPT charge controllers, which will prevent over-charging. Anyways, I hope to pick up another engine larger engine when I can, but it all takes time and money.

[@regularpit1508]

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

[@michaelorr430]

Fun project! You can set that up with a "loose/slipping" belt then add a lever with a tensioner pulley so that you can easily start it , then pull the lever to bring the tensioner pulley up against the belt to engage the generator. You may be able to change settings on the charge controller to set the max charge amps considerably lower so that the generator doesn't bog down to an under voltage and low rpm condition, Tinkering is fun and I enjoy your videos, keep it up!

[@backyardmachinist]

This is great! You said that the engine is 3 HP. Combustion engines are at best around 36% efficient, so it makes sense that it was only pumping out 800 of those twenty-two hundred theoretical watts. Great to have the ability to generate power with another source tho and keep your off-grid operation going! Thanks for sharing

[@DavidPozEnergy]

Your welcome, thanks for watching.

[@volodumurkalunyak4651]

@@DavidPozEnergy wrong. 3hp combustion engine is supposed to have max OUTPUT power at 3hp - at the shaft. Output power is 3HP instead of 3hp*engine efficiency.

[@keithwithnobs]

1 hp is or equals to 746 watts. Looks like you need a 6hp gas motor. As you are overdriving your generator with a bigger drive pulley than the driven pulley. So you need to do some math. What is the rated rpm of treadmill motor. All small gasoline engined are rated hp at 3650 rpm. Need to get pulleys to match reccomended rpms of each unit. Also consider mechanical loses by the belts and bearings. It will work. When you do get. Build a small hydrogen generator and you can run your unit of just water n baking soda. I run a 12 500 watt generator on hydrogen. I. Use a 10 amp battery charger off my generator output to power the electrolosis. I start the gas engine on gasoline. Once is running and producing electrical power i switch off gasoline and over to hydrogen. I enjoy your videos. Very well done. Hope you have success with DC generator.

[@DavidPozEnergy]

That's awesome you run yours on hydrogen.

[@keithwithnobs]

@@DavidPozEnergy Easily. The engine on my 12 500 is 13hp. It takes about 8.7 amps to make enough hydrogen to run it. So for you. You could make a generator that only uses 5 amps 12 volts to make enough fuel to run a 6 hp engine. My water mixture to make hydrogen is 4 tbsp of baking soda to 2 litres water. It converts fast and resists cold weather eg. Freezing in low temps. A tip. Use a daul fue carb conversion and feed the low psi hydrogen into lpg regulator. You will need to adjust for hydrogen. But it sure makes it easy to run hydrogen on gasoline generator with varying loads.

[@onlyscience7120]

Energy can neither be created nor destroyed - only converted from one form of energy to another.

[@mikeb.2166]

When the video started I was thinking you were going to be running on the treadmill to charge your batteries - LOL - like making good on a new years resolution! The video was very entertaining, educational, and great job overall. Looking forward to the next one where you modify this with some of the viewers suggestions.

[@DavidPozEnergy]

Thanks for watching. Yes, I'll do some more testing with viewer suggestions.

[@ai4px]

Hi David.... you should try a love joy rubber coupling. A lot less friction. Also that new EG4 100amp 48v charger from SS looks perfect for dirty power contractor grade genesis and your MEP 802.

[@offgridwanabe]

I like the idea of using a DC motor for charging the battery bank seems you need to know the rpm required to reach the watts you want then size the pulleys to make that rpm you may not need another gas motor but even before you started I figured 5 hp needed (just guessing) so much power lost in the belt, an old snowmobile engine with the clutch pulley may be interesting. Thanks for sharing and letting us see your process.

[@stormer6364]

Great little project, nice idea.. I'd probably add an Ac spike suppression cap as well as the choke to prevent Ac spikes from the motor from damaging that controller, it might be a little sensitive..

[@McCuneWindandSolar]

Now thanks to you I have a project I want to try and build LOL. Using an old wind turbine I have.

[@johnathanstheater]

Very ingenious ! Always amazed at your engineering skills. Along with your fabrication .

[@DavidPozEnergy]

Thank you very much!

[@TheWickerShireProject]

Love the Idea of a choke to clean up the DC power. Sad the pull start wasn't working. Choked that should of started. New engine maybe needs to be broken in? Crazy how bad it bogs down at a higher Voltage draw. Pulley sizes will play into the build for torque. Love that engineers brain and the reuse of so many original parts to create a mount ect... We miss and love you Dave! Good video!

[@TheWickerShireProject]

Look into Moped Torque converters. They change in size and have different weights in them for adjustment. See and old bike somewhere GRAB IT!

[@DavidPozEnergy]

I miss you too buddy. Looks like you are having a blast out on the farm.

[@TheWickerShireProject]

@@DavidPozEnergy Rainwater system going in soon. I'm doing water filtration video's as we near construction. Felt the need to break down whatever components one might think they need and how they work or do not work as intended ( via company info or science?)

[@DavidPozEnergy]

That's great. I'll guess, a Jakery?

[@tincankiller6454]

Great video David I made a similar system except it is driven by a bicycle with one of those stationary bike stands. With more time, more modifications it can be set up for multi-volt, but for now its 12 volts, works pretty well. It's also a good work out. Stay Safe & Good Luck

[@oscarvogel2140]

I made a peddle powered generator out of one of these too. They are wild DC, the faster I peddle the higher the voltage. It runs an osterizer blender with no added circuit. I used a J6 belt like the stock pully for the motor usually has and it went around the outside of a 26" bike rim. to get it going fast enough.

[@gregorytrenhed8318]

I have been watching your videos for so long and I gotta say your have truly grown in all aspects and I love how you use all the stuff on your mission

[@DavidPozEnergy]

Thank you, I appreciate it.

[@FRANK101101101]

800watts is about 1HP, the engine is clearly not producing its 3HP rated power. As someone else commented, smaller pulley on your engine for less RPM at treadmill motor but more torque.

[@energetictv9340]

He would have to run it at peak torque to make it work. Many engines are over rated in small engine world. Almost need to get double the rating to get a good result

[@bobbinatorrah67]

Great video. It really shows how much power several hundred horsepower is, and even gives me more respect for 400W solar panels.

[@SoutheastOhioSolarHaven]

I think the Issue maybe that the Victron Charge controller is searching Maximum Power Point right off the bat. I notice my Victron controller doing that sometimes after I reset and or turn it off. So that might be the Issue. 2.5 Hp motor with Fly wheels on it. Shouldnt be a overburden for 3 Hp engine. Try again but limit output max amps in charge controller and then adjust amps upwards . Or maybe let it run full out and see what happens.

[@DavidPozEnergy]

Thanks. I have been messing around with the Victron settings off camera. So far, I haven't found a way to get more Watts. I was figuring the same thing about the 2.5hp to 3hp.

[@mitsos_306]

One of the most decent projects I've seen!

[@kevincrawford2027]

I am using a permanent magnet motor as a generator to charge a 24 volt LiFePo4 system. Mine is driven by a water wheel instead of an engine. I had it hooked to a Epever mppt controller. When the batteries got charged and the controller cut off the voltage would exceed the controllers max input voltage. To remedy this I put a voltage controlled switch on the input side of the controller to switch the input to a load resistor when the batteries were full. I think you could use the same idea to shut off the engine ignition when the batteries are full or what ever voltage you select. Otherwise you may need to find a controller with a much wider voltage range. Been enjoying your videos.

[@DavidPozEnergy]

Sounds cool. Thanks for sharing.

[@freeinwy1]

Hey good job. By the way I’ve done a lot of fabrication and inventing for my own off grid situation. I’m a master diesel mechanic and have been off grid for about 2 years. I put an add on Craig’s list asking for old car batteries that I refurbish with my dc welder. I’ve used old treadmills for various projects. I just wanted to tell you the belt that you would’ve walked on makes a good all terrain creeper to slide under a vehicle. 😊

[@maxring837]

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.

[@davescorneroftheworld1147]

I did the same thing 35 years ago with a 10HP gas engine and a TRUCK alternator. I used mine to charge bulldozer batteries and other heavy equipment batteries. The DC was not as clean but all I was doing was charging engine batteries.

[@maximemineault8117]

It is amazing to see the charge controller trying to maximize the output of the motor. One thing I think would help is if it is possible to set the charge controller to hydro. Solar mppt are super agressive in their quest to find the peak efficiency. If it was on a hydro or wind mode sort of mode it could be gentler and adjusting slower the maximum power point. In the video, the mppt is not dropping the amps fast enough to let the engine ramp up to try a gentler load. That said, I think it would be safe to limit the charge controller, as if you put a big engine, I think it will burn the treadmill motor.

[@rkeantube]

man in the apocalypse you going to guy to have on the team

[@okielicious]

You could hook 2 12v batt to get 24v and power the treadmill motor to start the gas engine. Like the old cub cadet riding mowers. Then reverse it back to charge mode with a switch.. just an idea! Good build !!!

[@awbean5254]

DAVID, GOOD THOUGHT PROCESS!

[@calcoindustries]

I like running rough number math to figure out why something does or doesn’t work. You can find a video of this exact engine brand new being dyno tested and it produced approx 2.85ft-lbs peak torque. That motor is 2.5HP @ ~7000rpm with no load which equates to about 1.9ft-lbs of torque. Have to really guess on the ratio of the pulleys you attached but by a quick glance it looks like it could potentially be 1:2 which means double the rpm, halve the torque. So now your motor is outputting 1.4ft-lbs, minus any losses of belt slippage and pulley friction. Based on that, it makes sense why it bogs down when approaching full load. Diesel engines of the same HP will have a higher torque rating and the fuel consumption isn’t affected by torque load nearly as much as a gasoline engine. Love the concept, I’ll eventually build one myself in the future. Correct me if I made any mistakes.

[@ronaldclark1178]

A pull handle for tensioning the belt might help with starting. I had a mulcher set up like that. You had to completely release the tension on the belt to start the engine, then pull the belt tensioner handle until it tightened and cammed over. Good luck and Great video!

[@DavidPozEnergy]

Thanks. Maybe the bigger engine (6.5hp) will start easier?

[@ShaneS071]

I started making a unit similar with a 24V alternator , stripped all the guts out and connected the 3 phases to a bridge rectifier that they use on wind turbines, still working on it when I get time, planing to connect it to a midnite solar charge controller, I started off with the Predator 6.5hp(212cc) engine

[@johnanderson2591]

I built same set up for 48 volt bank. Added large shotkey diode and intermittent toggle switch to apply power to motor from battery bank. Electric start.

[@djstraylight]

I always thought that a small diesel engine would be great for a DIY generator. I make my own biodiesel so this has inspired me to get all the parts I will need DIY diesel generator. Probably find a DC motor in the 2kw range.

[@bobhale8325]

Interesting use of an old treadmill.

[@580guru]

Nice David! ❤️ re-purposing junk into what you need.

[@chrisdekock8864]

Great built my friend! I think that a PTO/direct drive will be a great addition, also a governor of sorts, like a selectable charging current to get to the sweet spot for your engine, to take advantage of the best of the power curve. I live on a sailboat, and im looking at doing a straight 175A alternator to a 6hp diesel engine for power generation in long winter nights and rainy cloudy weeks

[@bumbarabun]

"also a governor of sorts, like a selectable charging current to get to the sweet spot for your engine" MPTT charger if it is in proper mode should do that automatically.

[@fsj197811]

Great idea using the treadmill motor. I've seen builds using a small engine and a 60A(?) automotive alternator and I think they were using a 5hp engine and having the same problem you did. Thanks for sharing.

[@Ski098]

That motor was crazy. Hard to start. Just need a bigger jerk on the rope. ;) (Sorry, couldn't resist. Great video!)

[@Steelythestacker]

Awesome work man. The only notes I would give is maybe a change in pulleys to adjust your torque a bit better and maybe a centrifical go-kart clutch to aid with starting. Other than that top notch work bud.

[@mudkingz6432]

A small gasifier hooked up to that setup would be a true off grid solution plenty of sticks to use.

[@troy3456789]

Very interesting and seemingly right up my alley. I have the same kind of hydraulic crimpers you have. I also have a victron bluetooth shunt for my 100 amp hour battery. I just need about 30 more of those hundred amp hour lithium iron phosphate batteries and I'll be set for a minute.

[@neverdemagain6043]

Oh wow!! I find old work out equipment and use the tube steel also. Tube steel is stupid crazy expensive right now.

[@johnc7431]

I wrecked mine up with a 5.5 Honda engine put a Delco Remy alternator. Put a current switch on it. Just like you I started messing around. How I could charge my batteries the alternator works great

[@bruceeverett5372]

A 79cc motor is common in small inverter generators but it turns at 5000rpm to get the hp required, but these little thumpers are only for around 3600rpm so they can't get to that power curve. Get a Predator 212cc and it will make all you need!

[@74HDJOE]

Some people are giving you some ideas and advise that might be of help to your project. I'm pretty sure that you'll have all dialed in very soon, It looks good so far. 👍

[@dodgydruid]

Interesting vid, I have a very old Italian Aspire engine which is a licenced Tecumseh from the 60-70's that I want to build a generator with, over here in the UK we only have 240v so a DC motor would be hard pushed to backfeed my ring main but I think I will go the alternator route and maybe make a supercapacitor overflow cell that I can charge lighter devices on the 5v 12v range. The engine was a genuine find in itself, never used just sat in a shops storeroom for decades and I bought it for £20 delivered too :D I converted my car to supercapacitor cell and it works extremely well esp as I have done the whole lighting with LED's, no incandescent anywhere on my little car, makes it very easy to start esp in cold and it is full charge in seconds from start.

[@drevil4454]

This is why I like youtube. Normal guys doing normal shit

[@elmetbrown656]

Hi Dave I would leave the ribbed strap on and not a v-belt use the ribbed belt runs more easily and needs not as much energy as a V-Belt. Otherwise great work as always.

[@raulorona7090]

As rule of a thumb you need 2.5 hp per 1 kw in a perfect set up, i make mine with a 5 hp engine with a 1 hp permanent magnet DC motor, RPM is 1800 runs at 90 VDC 10 amps. can take out the same 900 watts. after 5 hour running, motor begin to get hot is not designed for generate power but works. If you can find a Brigs and Straton engine got less vibration than predator engine and ad a flywheel for easy start and remove some vibration too.

[@anthonyalleyne8724]

Great video! I did the same thing a few years ago. To take of the treadmill pulley, one must remove the fan first, tighten the shaft and turn the pulley either clockwise or anti clockwise, I can't remember! Its left hand thread!

[@GeevyLic]

David, think of it as a transmission when a guy goes up a hill and needs to shift down to pull the hill.it maybe easier to get a smaller pulley for the engine. Or a bigger pulley for the generator good luck!

[@thehumbledabbler]

A treadmill flywheel is always reverse threaded. Hold the shaft at the rear with a pipe wrench and turn the flywheel by hand. Works everytime.

[@georgedoherty962]

The more of these that you build, the better you get. A 4 rib gates belt developed less friction.. and as someone else has already mentioned, the pulley ratios need to be investigated to find the sweetest spot. I found that using a variable speed drill or angle grinder gave me the correct pulley ratio.. My biggest success was a 2kw x 120vdc permanent magnet generator from a Chinese wind turbine. I had to have 5 different pulleys to find the sweet spot. I use a 10 horse yanmar clone. It cost me €2 000 before I got it all finished to my satisfaction. It is our standby generator that charges our 60 forklift cells. It is set to charge at a max of 12 amps x 146vdc. By tbe time it reaches 146vdc, tbe engine is pulling steady and tbe cooling fans on tbe PMG and engine are blowing nice warm air. It never runs more than 90 minutes. Mostly 60 minutes. It is the most efficient way possible for generating ones own electricity when wind and solar are not active. I built many Btiggs and Stratton x 180amp ValeoN47s. These are a fantastic success.

[@DavidPozEnergy]

Sounds fantastic. Do you happen to have a website, or someplace I can learn more about your system?

[@georgedoherty962]

@@DavidPozEnergy I never had my own site in all the years that I was a moderator on the "Navitron Renewable Enetgy Forum" most of my projects were posted there but when the forum was shut down in May 21, all the data and posts disappeared with it. I know that it can be retrieved from "The way back Machine" with a lot of work and patience. The "Wayback Machine" Carry,s the files and archives right back to 2012.. I have not used it myself.. I don't know if you can post pics on here.

[@simonallan9941]

The 3hp should be ok at a continuous 6-7krpm, if you can put a smaller pulley on the engine and let it rev, and you can make them put out more power as well, change jet and exhaust, also air cleaner, especially in a cold environment it may want a richer mixture with a cold air intake 😉, great video thank you awesomely for sharing your experience and experiments, I wish I had that kind of equipment available for my off grid power supply

[@gliOrtidiMauro]

ciao David, io ne ho fatto uno con un motore da 6.5 Hp, in una sega circolare che utilizzo per tagliare legna e con un alternatore auto carico le batterie... il mio alternatore eroga fino a 55 A , rapporto che ho fatto sulla puleggia è 1a2 così il mio alternatore raggiunge i 4.500 rpm tenendo il motore a poco più di 2000 rpm. tagliando legna non ho più i tempi morti e posso stare sereno che nelle mie pause il motore gira e intanto carica le batterie... l'idea del tappeto recuperato è geniale. bravo grazie.

[@mcook407]

LOL Oh come on David just rig the treadmill so when you run on it you generate, ya it's hard work BUT! Great Vid Sir, I just love the ingenuity... back to the show!

[@peterparsons7141]

While I was watching the video, I was thinking one of the old 3 horse diesels with a great big fly wheel would be the ticket. At the end you mention , perhaps a diesel ? The more I see video’s like these the more I like the idea of diesel, especially if you could get one to run on a cheaper fuel. Good video’s and lots of good idea’s.

[@DavidPozEnergy]

Yes, I agree that diesel is the way to go. I have a video on an army generator that I'm currently fixing up. I hope to do testing on that this summer

[@peterparsons7141]

@@DavidPozEnergy I saw the 3kw military generator you did. Seems like a lot of machine for 3kw, and really expensive in Canada. I recently retired rural, and have been considering how to have alternate power sources. The big part at this time is identifying how much power does a home, my home need? Air conditioning and refrigeration, electronics are the big thing. Heat, light, water are easy. I will continue to follow your channel for help with wiring etc. 40+ years ago my uncle had a diesel generator setup in a insulated shed, with large battery banks and it worked fine. I’m hoping In 2023 I can assemble something a little more modern, but just as bullet proof. Keep up with the vids, they are informative and fun to watch….and selfishly it saves me from having to try all this stuff!

[@BigHeinen]

That's actually a pretty brand of treadmill named NordicTrack. Also, the 3hp Predator motor is capable of only 2,206 watts of power (if it truly is a full 3hp??) before any mechanical losses so it is underpowered as you found out. Thanks for a great video!

[@byronmill]

Yes, they're not really a 3 horsepower engine. Peak torque is 3.5 lb/ft at 2500 rpm. Torque at max RPM of 3600 RPM is about 3.15 lb/ft, so about 2.16 horsepower under ideal conditions. Belt drive is considered to be .85 efficiency. I think the 800 to 850 watt output that he was seeing is limits of the engine, even if he tweaked the pulley ratio.

[@viennatech]

3hp is just over 2000watts equivalent so there are inefficiencies in your system. I’d suggest going with a bigger pulley on the generator side. You want the engine to run around 3000+ RPM to have its best torque. You could also tune it in the controller to only pull 6-8amps max and settle with the resulting charge rate?

[@calarndt]

David smaller pulley on predator would increase the engine rpm. That would do two things. 1. It would allow the motor to run the generator at closer to the predators peak on the torque curve. 2. It would also lower the load on the predator at start time. I don't have a calculator handy but 3hp should be pretty close to all you need for an 1800 watt load.

[@bitworkx6028]

Great repurpose idea. Just thought if you pick uo another treadmill that looks dead and wished you had a working treadmill, theres a battery compartment underneath the big display box ( bottom of the unit). The battery powers the display. Mine went dead and I luckily found the spot, changed the 9v battery and the unit worked again

[@DavidPozEnergy]

Good to know. Thanks.

[@joshwooten3719]

Hey David, funny your video popped up because I just attempted to install this exact treadmill motor on a dt466 powered school bus to charge our SOK server battery while we're on the road. In about 5 minutes I discovered that the back plastic cap that holds the brushes is a weak point on these motors as it is also the rear bearing housing and some thrust load from the engine belt pushed the motor shaft clear through the back housing. Basically, watch your belt tension. This is why they come with a 10 groove serpentine pulley, it has much higher surface area than a v belt and therefore doesn't need to be tensioned as much. I'm currently replacing it with a treadmill motor I found that has metal bearing caps front and back and hope this solves the problem as we're hitting the road today headed to Florida for a 1 month boondocking trip.

[@DavidPozEnergy]

That is funny. I wouldn't have thought to run it in a school bus conversion. Let me know if you post a video, I'd like to see it.