The AlternatorGenerator, First Attempt. 48V Battery Charging

Will this even work? 48V alternators are expensive. Can we make one from a standard 12V car alternator? I don't know, which is why I decided to try. This video a a complete walk-though, start to finish.
I bought a 12V car alternator off of craigslist for $100. I wasn't looking for any specific model, but I wanted a serpentine pulley on the alternator, and it had to look decent. Next was a Predator gas engine from Harbor Freight. In this case, I purchased the 224cc MAX engine, which is 6.6hp. The 212cc 6.5hp engine would have also worked well for this build.
The goal is to make a dedicated generator that can recharge my 48V battery bank. I'm using the EG4 LiFePO4 batteries, which is a little more than 30kWh. Sometimes, during the winter, the solar production doesn't keep up with my loads. That's when I need to supplement my solar with some generator run-time in order to recharge my battery bank. Yes, 48V generators exist on the market, but they are thousands of dollars. I built this generator for about $400.
Intro: 00:00
Theory of Operation: 00:43
Parts Used: 04:44
Alternator Wiring: 07:04
Building the Base: 16:43
Drive Pulley Installation: 21:05
Wiring the Busbars, Rectifiers, Buck Converter, and Capacitor: 27:45
Test Run: 38:29
Conclusion: 44:20
Amazon affiliate Links:
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Capacitor, 450V, 1000uF: amzn.to/3lTHopw
DC to DC Buck Converter, 12V 5A: amzn.to/3nug0yK
Charge Controller used in this video (Victron 250/100): amzn.to/40k4kNz
Less Expensive Charge Controller: amzn.to/3K4fZJE
Engine Hour Meter and Tachometer: amzn.to/3KhxMhE
Vibration Engine Mounts: amzn.to/3nmbbaz
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Busbar set: amzn.to/3M4plYq
Circuit Breaker: amzn.to/3M3N1w6
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Tachometer, Digital: amzn.to/3Kl1ken
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“As an Amazon Associate I earn from qualifying purchases.”
Harbor Freight Links, Not Affiliated:
6.6 Hp, 224cc, MAX: www.harborfreight.com/generat...
Band Saw: www.harborfreight.com/power-t...
Tap and Die Set, SAE, Titanium: www.harborfreight.com/titaniu...
Note: I have no affiliate with Harbor Freight.
Previous Video making a battery charging generator from a free treadmill motor: • DIY DC Generator: char...
Signature Solar Affiliate Links:
Battery Bank, EG4-LifePower4, Lithium, 30.72kWh: signaturesolar.com/eg4-lifepo...
Inverter kit, Schneider XW PRO 6848: signaturesolar.com/bndl-ac-co...
Chargeverter: signaturesolar.com/eg4-charge...
Disclaimer:
My videos are in no way intended to be instructional "how-to" lessons. I am simply documenting my project for informational purposes. Property damage, personal injury, or death may result, even when following manufacturer's instructions. I cannot be held liable for such damage or injury. It is YOUR OBLIGATION to ensure that you are complying with any local and federal laws as well as code and permit requirements.
David Poz, LLC

[@DavidPozEnergy]

Part 2 Video is out: kzbin.info/www/bejne/maqTpWenpp2giZI It includes a fuel economy test, thermal imaging, vibration fix, and I answer your questions.

[@Mike80528]

Be careful with that circuit breaker. I didn't see a DC rating and high current DC circuits can be a lot harder to trip than AC (have been known to cause issued with solar...)

[@jackoneil3933]

Thanks David! Very interesting and informative test. I just watched your follow-up video and in Alaska connected the exhaust of air and water cooled generators to a coil stainless steel and copper tubing, and immersed the coil as crude stack robber and estimated I was able to recover up to about 20% of the thermal heat energy from the engine. I mounted the generators above the heat exchanger coil inlet and plumbed the outlet out the bottom of a spray-foam insulated fiberglass or steel tanks so the exhaust condensate would drain out. On water cooled generators from 7kw to 600kw we installed coolant heat exchangers to the engine coolant system, removed the engine thermostats and used AMOT valves (Thermostats) in the heat exchanger loop to maximize heat recovery. Combing engine heat recovery with commercial exhaust to water stack robbers recovered up to 60% of the engine heat, so basically the fuel cost of our electric load provided heat most of our space heating. I was thinking a heat recovery might project might be interesting for viewers, and I would be happy to provide insights from my experience if needed.

[@Thunderstormworld]

The best generator I built 15 years ago , consist of a 200cc gasoline engine and a 12 volt alternator and a 12 volt 647 battery and a 1000watt inverter. What makes it extremely better than a normal generator mine can run 2 hours without needing to start the engine so instead of running a normal generator for 4 hours on fuel it use only half , couple this that it's connected to solar panels , my next aim is connecting to a wind turbine .

[@dodgeme1986truck]

Add a heavy flywheel to the engine as it will stabilize engine power pulses allowing less vibration and more/stable power production

[@1crazypj]

@@dodgeme1986truck A single cylinder industrial engine without balance shafts is always going to vibrate pretty bad

[@D2O2]

Great video David! Some suggestions, rigid mount the engine and alternator together on one frame, then iso mount that frame to your platform. This will help maintain proper belt tension and reduce overall displacement and vibration.

[@Jody_VE5SAR]

I second this idea. As it is now, the dynamic response of the engine mounts can cause slack in the belt at various resonant frequencies. A fixed relationship between the engine and alternator would solve this (either still using a belt, or via direct drive). Also - just a thought - it might be possible to use the motor's magneto to provide the necessary kick-start to the buck supply.

[@chrisw6690]

I also agree. As it is now the belt tension is side loading the isolators to the point they probably aren't very effective and will fail after a while. Even in a vehicle the alternator is bolted directly to engine (yes their maybe brackets but no isolators) and then entire engine assembly is on motor mounts(isolators). But otherwise I thought this was an awesome video.

[@-Gadget-]

Good idea, but then build an open frame/box that is slightly bigger than the whole unit, and suspend the entire unit within the cage/box with bungy cord or springs. Springs should theoretically remove 100%of the vibrations before it even gets to the frame/box 🤔

[@jwray9799]

I replied the same fix too,, before I saw yours ///perfect idea!

[@barrellcooper6490]

This was my first observation too. Motor and alternator need to be rigidly joined so the belt can function under constant tension.

[@TrackGeeks]

This is one of my favorite projects you've done so far.

[@DavidPozEnergy]

Thank you. It was a lot of fun to build.

[@TrackGeeks]

I appreciate the effort and tenacity you displayed to get it working.

[@mukhtarosman2492]

​@@DavidPozEnergy hello mr david i intrested u re vedios i am in somalia i want to use 24v by car alternative is that posible?

[@jmacd8817]

​@@mukhtarosman2492 your best bet would be an old military alternator, as most military trucks run at 24 volts. It's also possible to find an older diesel truck alternator, as they used to be 24 volts, but not mostly use 12. This would simplify your setup, because you could use the alternator "as is" without having to modify it. Google could help you find what make, model, etc of alternator to look for.

[@Swampwild1]

Fascinating project. Made me look at what you can buy for this because I’m not anywhere close to skill level for trying even with your excellent and entertaining video.

[@spkay31]

"David - I'm not an electrical engineer - Poz". Well I have 2 degrees in EE and you sir are one hell of an imposter! Seriously great work all around. Love the combination of electrical, mechanical, carpentry and general problem solving skills to pull off a reasonably challenging project and produce excellent results.

[@DavidPozEnergy]

Thank you, that's one heck of a compliment. I appreciate that.

[@Willam_J]

EE/Physicist here, as well. (Retired) It's always enjoyable, watching someone tackle a project, and NOT use zip-ties and hot glue, to hold it together. It's also nice to see someone actually engineer something, instead of just slapping parts together and hoping for the best. There are a lot of electronics channels, on KZbin, but very few that I'll actually watch. I see way too many good ideas, never come to fruition, due to a lack of knowledge, and/or poor construction skills. I will also attest, that this guy is 'the real deal'.

[@habeelkhan6532]

​@@Willam_J Engineer never retired 😂

[@richardbilous5338]

You've always been great at teaching! I miss ya so much! Thanks David & the fams for everything you've done for me! Even though it was many years ago I still remember those days as a kid watching ya do your projects! I'm glad your still doing your thing!

[@LithiumSolar]

Wow, very interesting build. I thought it would work but didn't expect over 3000W! Not sure how, but definitely need to secure that pupper down as it was starting to walk away lol.

[@DavidPozEnergy]

Thanks Lithium Solar. Yes, I was surprised. I was hoping for 1600W. I came to that number because when I built the treadmill generator, I used a 3hp engine and got 800W. I figured double the engine, double the power out. So, this blew my mind. I had to record my conclusion over and over again because I was so giddy. LOL

[@Michael-rz7ic]

Wow, what a fun project. Thank you so much for the theoretical walk-through before the build. Now how bout some type of diesel engine with that alternator? Maybe off the pto of a small tractor, or an old John Deere diesel garden tractor??? Could be a lot of fun.

[@jonasstahl9826]

I would be careful to not overheat the alternator, they are not meant to produce there full power over extended periods of time.

[@whatta7793]

Same, I knew it would work, but I was expecting maybe 1500 watts give or take. But 3000?!?! That shocked me greatly. I know alternator sizes vary from car to car, but for example, my 1999 Tahoe has a 105 amp alternator, charges at 14.8 volts when I first start it, and drops to 14.4 volts after everything warms up. That's where I got my 1500 watts give or take figure, but this little puppy done over 3000 watts!

[@kingi7607]

i wasnt expecting it to output a whole 3kW, thats awesome. fuel consumption tests at different loads would be interesting to see.

[@DonKees]

Hi David, I really enjoyed the video. You mentioned raising the 12VDC input from the buck converter into the rotor. I would advise to measure the rotor current and increase slowly and carefully since it may not actually increase your output power as you were already getting the rated output power for the alternator. The rotor winding will magnetically saturate and then the extra current will only overheat the rotor and it may be damaged as the wire gauge is really small. Kind regards.

[@kennethdegruchy5503]

The source of 12 volts for the field is constant however in the actual automotive application I believe the field current is duty cycled from the voltage regulator dependent upon the total load. The point is you are maxing out the field so I wouild not think it a good idea to raise the field voltage/current any further to avoid over heating the field winding.

[@frankstocker5475]

You are every young boy's dream uncle. You proved it works now I see improvement in the drive belt connection & maybe a temperature gauge on the alternator. Well done.

[@russ22f]

Fantastic. A fuel efficiency test comparison with your other generators would be great. I thought the pully would be too large to start the alternator charging on under load. I think the lower torque curve of the engine had to help in that regard. Very enjoyable video to watch.

[@rbartsch]

I'd really like to see a fuel economy test! ❤

[@alwaysbadideas]

I think this is going to be lower efficiency in general because alternators use some of the energy to self excite. Generators have permanent magnets which distinguishes them from alternators.

[@M35a2guy]

I would love to see the comparison vs the Big honda and the little one you rented. Interested to see how they stack up.

[@JbVest]

@@alwaysbadideas mine pulls about 25-30 watts to excite the rotor enough to make some good power. 2.4kw

[@dantronics1682]

@@alwaysbadideas the advantage with alternator is you can keep the output voltage stable at any speed where a genarator have a mean curve.

[@Razza2250]

Great idea. Great execution! My advice on belt vs direct drive would be to leave it as is. The alternator is turning at a good RPM for sufficient cooling while staying well within its design limits for RPM. Running it slow is going to mean less airflow over the stators and therefore more heat and lower efficiency. I also think you might be hitting the limit of the motor here more than the alternator. The MPPT won't load up the alternator any further as the RPMs fall, its going to find the sweet spot where the motor output is limited by its torque. You might be able to get a little more out of it, but honestly, the limit here is efficiency. A typical alternator is around 50-60% efficient. Being generous, that means 3kW out requires 5kW in from the motor in the form of mechanical input. A predator 212cc is a 6.5hp engine, which is 4.85kW. That's about bang on for what you can expect this motor to give and, as you observed, she was a-strugglin'! The alternator is rated by its current, so if you're pulling 120A from it, the voltage is not important as the heat generated in the stator is defined by P=I^2 x R. You would need a much more powerful motor to bring this alternator anywhere near its limits (around 12hp would be about right), but then you would still have that low efficiency of the car alternator ruining your litres to kWh ratio. Still, this is an amazing and cost effective innovation and I've been stewing on this idea for ages wondering if it could work. Bravo dude

[@JbVest]

would you have any input on how to wire an alt with 3 separate windings?, its not in the wye config it was wired in the delta config instead, what was weird to me is that there was only 8 diodes on the rectifier

[@buddyrojek9417]

I run a similar setup using a bigger motor but I run it on charcoal gas so I have zero running costs

[@gta-6837]

Your comment was insightful

[@dougbas3980]

I would think the alternator is rated 3kW only for a short time before heating would be harmful to the alternator. A long run at high out put with testing alternator temp would be interesting.

[@neiloconnell2120]

David. Very well done. I am impressed with your skill set. Great video.

[@BruceS42]

I got here kind of randomly, never heard of the channel before, but the video title was interesting enough to get me to start. The quality of presentation kept me through the whole thing. Nice work! I've done some builds of my own over the years (I'm 58), and appreciate the work and planning it takes to get something to really work. Thank you.

[@DavidPozEnergy]

Hi Bruce S. Thanks for watching through the video. I appreciate that.

[@remix381]

I have been watching your channel for sometime now and find your projects to be very educational. Thanks for the great content!!

[@urieaaron]

Even though I will probably never build something like this project, just one thing all by itself made it well worth my time. Watching you build your own adapter with little more than a drill press, a file and a tap was a learning experience and inspiring.

[@DavidPozEnergy]

Yeah, that was fun. It was about midnight, and the stores were closed. Not that I could have bought an adapter even if they were open, LOL.

[@blakeburgess7171]

I've been using waste vegetable oil for years, my standard ratio is 4 gallons waste vegetable oil to one gallon of gas, I have a 1982 Isuzu imark diesel engine that I've put in 3 different cars, I have saved over 50k $ in the last twenty years in fuel costs, this past winter I've started using a 5kw diesel heater with the same formula of fuel, it done a great job saving me money on my fuel bill, me and you have similar goals (off grid) I can buy a small diesel engine on Amazon for around $275, I don't know how compatible it would be with my fuel formula, I might need to tweak it some, or I was thinking I could just run my car to charge batteries, any suggestions would be greatly appreciated, I'm clueless to electrical and solar systems

[@blakeburgess7171]

I work in a restaurant and I have unlimited supply to waste oil

[@1982MCI]

@@blakeburgess7171 and I was just going to ask you where you were sourcing that much waste oil at but you read my mind! Thank you Blake

[@cannaroe1213]

@@blakeburgess7171There are two issues with bio-diesels, can the injection system handle it, and can the rubber/plastic parts in the fuel system handle it. Older cars typically answer yes to both. Newer cars depends, the limiting factor is usually the injectors, the rubber parts take a year or so to degrade if not correct. lots of videos on youtube about it

[@rdh2059]

You may want to consider changing the position of your pully on the shaft. The farther out you put the pully, the more torque you are putting on the shaft itself. I suggest putting the pully as close to the engine housing as you can, with "reasonable" clearance. That will make the engine crankshaft bearings last longer... It looks like you are mounting to the heat sink backwards. You should be connecting directly to the thick part of the heat sink plate. The fins are designed to dissipate the heat, NOT be the side to mount the components to. Put the pad inbetween the thick side of the plate and the components...

[@philcamp8621]

and possibly make the shaft seal leak oil with the load being that far out flexing the crankshaft. IMHO 😎

[@aXBlackDeathXa]

I knew from experience it was absolutely possible to get more voltage out of an alternator however, I never dreamed to use one in the fashion you did. I did not have doubts you'd get a result I was just uncertain to what degree. Your results were obviously impressive. I'd be very interested to see how the alternator holds up over extended use. Thanks for sharing!

[@rklauco]

When this started, I thought this will never work. Yet, it not only did, but did beautifully. Congrats!

[@geetootiger5418]

Nice setup and your electronic knowledge is amazing! The reason for the slack in your drivebelt is that the alternator is fixed to the baseplate, while the motor can move in its rubber mounts. You should install both the alternator and the motor on a metal plate or frame and then connect the whole assembly with rubber mounts to the base plate.

[@cartmanrlsusall]

That sounds very reasonable

[@stevesawyer6377]

As usual, great video. Always appreciate the depth of your information and how well you explain everything

[@charleyevans2811]

I really enjoyed your video. As an 1st yr electrical apprentice, this video really helped me to understand things I haven't see on the job

[@peterryan7340]

I would love to see a thermal view of various components during running at various rpms.

[@onedayatatime723]

rpm *

[@glennimmortal]

@@onedayatatime723 rpms's

[@QuackGoesTheDuckQuackQuackQuac]

@@glennimmortal rpmses

[@AutodidactEngineer]

@@QuackGoesTheDuckQuackQuackQuac rpsexe

[@jpabon18]

You took an idea I had and brought it to fruition. With a few mods, it's perfect! You just gained yourself another sub. Do a fuel economy test on it next please. I almost forgot to say, GREAT JOB! 👍

[@edwinpagan4705]

My dude. You are amazing!!!! Nice build!!! And making that adapter for the pulley install. Big props

[@mtnsofutah]

Thanks for doing this, I have wanted to do it but I'm too cheap to start throwing money at it. Now I have a good idea of what to purchase for my project with only doing very little experimenting. Great information, thank you again sir.

[@samvalentine3206]

I'm not sure why this build is so fascinating for me. Probably because I always wanted to do exactly what you did. Good job! You built it based on sound theory and it paid off! It would be interesting to see how much gas it uses at a reasonable charge rate. When you pushed it to 100, that seemed to be too much - then you dropped it to 50. Maybe half way in between? 75? Then see the power output and get an idea on the gasoline usage. Awesome project and thumbs up, David!

[@davidrobertson1980]

Pretty sure he went to 60 Sam, and when I heard the motor struggle I thought "Nah David, you need to drop it to 50" and he did that exactly and smooth sailing from there.... definitely needed this drop or the motor would overheat being air cooled and efficiency would plummet and wear increase exponentially in the motor.

[@lbroome]

A few nice things to see would be the temperature of the alternator and the charge controller at full load for extended periods, and the amount of ripple in the DC to the charge controller.

[@rickrussell]

Yeah I'm really wanting to see an oscilloscope hooked to the various outputs.

[@bawatechreview2168]

Thanks for sharing sir. This video clip gives me an idea on how to use the alternator as a wind turnine generator

[@waynesharp1690]

Stumbled upon this video and watched the whole thing. Really enjoyed watching. Thanks 👍

[@vansgardens2304]

Great video! I’ve done similar building a welder, but I used the existing rectifier and used ring terminals to connect directly to the brush housing mounting screws (that have continuity with the brushes). I left the voltage regulator in place and just didn’t use it.

[@lexicase8805]

I think this was my favourite of all your videos to date, and its super useful with the victron controller since they're multi voltage, theres no reason you couldnt set it to 12v and charge a dead car battery in an emergency, or run a 24 or 36v off grid setup too. I think this is now on my list of projects id like to do myself 😊

[@porschmn]

Adding a idler pulley , like in the cars charging system, to the belt may help the belt tension in your setup. Great build, learned a lot on this build, some of which I'm still trying to assimilate.

[@dodgeme1986truck]

He should add an additional heavy flywheel to the engine as it uses momentum between engine power stokes to keep the engine spinning this is why it's shaking the shakes are the power pulses a flywheel evens out the pulses keeping the engine rotating at a more steady speed

[@jonasduell9953]

Idler won't do much, he loses tension with the motor twisting on the rubber mounts. It all needs to go on a steel/alu/extrusion bar frame/base plate then on rubber mounts to the wood to maintain perfect alignment. The way this is built, the pulleys are pulled out of alignment by the belt creating uneven tension and wear on the belt. That thing won't live long...

[@alexanderbinai9583]

David excellent of work, self explain.. continue with similar project. I am very interested in this project

[@EmperorBun]

This is awesome. Love the idea of de-limiting the alternator. I would also be very interested to see the fuel economy test-find the sweet spot and keep it running there. Another interesting idea might be to scavenge the waste heat from the engine to heat your hot water tank. Build your own combined-cycle heat and power setup!

[@CSEV661]

I would love to see a fuel economy test on this one. I know I'm not the only one that's been looking into making something like this.

[@JbVest]

Yep I know I certainly have been wanting to make something like this for my two giant 48 volt packs I built. It would just be a nice backup to the backup. Redundancy baby!! 😂

[@FraLin]

it will be a Desaster below 50,%

[@jamesgrossmann866]

As an electrical engineer, I'm really trying to figure out why you removed the original rectifier diode system from the alternator. I don't see how that modification did anything but complicate your design. the original diodes were cooled by the alternator and were designed for the high voltages involved. I also think a small, simple circuit could also be built to replace the regulator and regulate the alternator output. If it were designed correctly, you could be much more in control of the output voltage instead of just hoping it will work with your charge controller.

[@noneofyourbusiness6210]

Obviously the guy isn't very bright if he's using a gas engine to charge batteries in the first place. So there's bound to be other flaws in his logic.

[@TroyWarr1980]

​@@noneofyourbusiness6210 I assume you're trolling, but there's no meaningful difference in charging off-grid batteries with a generator vs. powering a home with a generator. In fact, the former is more efficient because you're storing extra energy you don't immediately need. This is just a back-up solution for times when solar isn't enough

[@researcher4good]

Totally agree. Remove regulator. Connect field wire to ungrounded side of brushes. Done. After seeing how easy that is, I'm going to use newer 200a alternators with the regulator removed instead of early 80s ford 100a designs with external regulators. I was wondering what the diode voltage rating was.

[@dandeson9723]

You learn from your mistakes, also the capacitor wires could be bigger or it should have been placed between the output and controller to minimize resistance, the wires carry alot of current between every cycle.

[@manuelsilva8640]

The car alternator bridge rectifier diodes reverse breakdown voltage will be from 60 to 100V. For the intended > 80V the diodes replacement was the right call.

[@russelljohnson6243]

Dude, your children are precious! Thank God for them and pray for them all the time!

[@om617yota8]

Great build! Will definitely be doing something similar! Would definitely recommend moving all your electronics off the platform with the engine and alternator, before they get vibrated to death.

[@ericdelevinquiere9902]

would love to see if this alternator can keep its output at 3 kw for several hours without burning up. That would be significant!

[@walsakaluk4630]

Of course it will. The stator is rated at 250A.

[@ericdelevinquiere9902]

@@walsakaluk4630 still like to see it, seen too many burn out with way less amperage going thru especially when placed in continuous high load with poor cooling situations.

[@mk-en9fj]

I was thinking the same thing. Every regular automotive alternator I've seen has gotten very hot when running at the high end of it's rating. Most are likely not built for a 100% duty cycle at maximum load. Must test it and keep an eye on temperatures, including the diode pack.

[@pieterbezuidenhout2741]

Alternator is going to overheat especially with Lithium batteries.

[@2pist]

I tried this with a 3 hp Briggs 40 years ago. As soon as I ramped up the field it died. Did you try slowing it down to see the effect on voltage? I'm thinking it wouldn't drop much unloaded. Are you using anything to control the field current? If the charge controller had a feedback loop you would be all set! Running the voltage up is decreasing the current through the windings so heat shouldn't be an issue. I'm happy to see this work. I should do a similar vid but tie it to my inverter and call it a generator. 😊

[@snjairbeater]

This is my first video I found from you and I did enjoy it. Nicely done. I will watch more.

[@lawrenceengel3330]

This is a fantastic and interesting project build, well done 👌

[@benw1333]

I would remove the vibration isolators(motor Mounts) from the motor and mount the motor and alternator and brackets to a solid rigid piece of steel then install the isolators on the bottom of that main plate to the base plate. This would keep the belt tighter and more stable. i think the sloppy belt was contributing to the roughness especially when under the greater loads. This was such an awesome project and i now have so much more knowledge about the many applications of a automotive alternator! Thanks for creating this video and sharing it David!!

[@DavidPozEnergy]

Thank you for the suggestion, I'll have to try it. I appreciate your kind words. It was a lot of work, and I'm glad you enjoyed it.

[@samvalentine3206]

This idea of vibration isolation sounds like a good idea - maybe worth testing? Great work! Thanks for the super-interesting project!

[@JohnBaker3000]

Without a doubt, you keep us geeks very happy! Very cool project!

[@joshuamheinrich4961]

Seeing A Man who knows what he needs put all of this together really Inspiring to me. If I can, I'd love to make one of these for myself.

[@DavidPozEnergy]

Go for it, it's fun. I have a part 2 video also: kzbin.info/www/bejne/maqTpWenpp2giZI

[@andyfarese5255]

truly a great video, your application of the scientific method is sound and this was a very helpful practical demonstration of alternator capabilities

[@justinneill3888]

Loved this project! I've always wanted to build something like this. Yes, please do a fuel economy test. Also maybe some data comparing the yield from a DC generator vs your AC generator.

[@wg6215]

Very nice setup. It might be a good idea to mount the engine and alt on a separate platform to isolate the electrical components from the vibrations. They will last much longer, particularly the cap. Also a fuel burn test would be interesting to see. Good luck.

[@johnbrumfield6311]

Grea job explaining exactly what to buy and how to build it thank you😊

[@renatocunha6974]

Amigo, seu vídeo é um dos mais raros relacionado a gerar energia através de alternador automotivo, pois todos os outros não medem a corrente limite do grupo gerador. Parabéns, vou montar um. 👏👏👏

[@dawgrules1]

Thanks for the video David, great information ! If you have not yet read it, "OPERATION OF THE LUNDELL CLAWPOLE ALTERNATOR AT HIGH POWER DENSITY AND EFFICIENCY" is a great read on this specific topic. It gets into using large alternators intended for diesel semi tractors and the author shares a ton of valuable information and a little history too.

[@user-mp9rd4hg8b]

I did something very similar a few years ago with a 10 hp diesel engine. I used dual alternators for power and also to charge/recharge a small battery bank for off-grid use. It works very well and is very reliable. Plus I get 10-12 hours of use out of a 3 gallon tank of diesel.

[@jerrybabatunde3380]

Please can you help me further with yours 10hp diesel engine design. I am thinking of using a bigger alternator for 10 tires dump truck. I really want to be 100% off grid

[@jerrybabatunde3380]

10 to 12 hours ops from 3 gallon diesel tank is absolutely impressive

[@dudeinaroom1238]

Nice user name....WTF

[@ryankim3612]

@@dudeinaroom1238 IKR!?! (I guess he can’t call himself “non-binary”) WAGGA-WAGGA…. I crack myself up!

[@timpeterson2738]

Use your name buddy.

[@jamesbiggs9981]

This was a fantastic video. Great job. Your explanations were spot on. Very very informative. Thank you. I pulled the rectifier off and tested my voltage coming from mine and I had three wires pumping out 120v ac each. I just need to figure out how to marry it up to my breaker box and try and power my garage from that. You have given me hope that it is more than possible. Again thank you

[@thinkingoutloud6741]

Great video. Thank you. Lots to learn here, and room for additional ideas. I think knowing the actual horsepower output of the engine would be interesting, rather than accepting the rated output.

[@thehairs2018]

Mount the engine solid to the board and use vibration control under the base. Maybe to another board with rubber feet. This would also help with belt tension. You could also use a turnbuckle for better control of the tension. Love the idea, and glad I found your channel to subscribe.

[@galen__]

Considering all the possible challenges and unknowns when combining multiple items together, I didn’t know what kind of result you would have until the ending. Thank you for sharing this with us.

[@uet7417]

Wish I saw this before I decided to get into metal casting to make a serpentine pulley with a 20mm bore for my diesel engine... Great video David!

[@joesantos3717]

We did something like that in 1988 when i was in high school....well done...

[@tomhardin8393]

Congratulations David. It works! It got my attention but in a different way. Some day I want to try this by powering it with wind. I had thought I would have to put 4 alternators in series (good luck with that 😮) but you showed a single alternator can put out enough voltage to work in a 48 volt system. I’m excited!

[@off6848]

It takes about 5BHP for a wind turbine to make 40ish amps on an alternator in builds I've seen. You'd need quite a large and powerful wind turbine to spin 4 alternators.

[@ThinkFab]

David, my dude, mad props for going after this build and actually documenting it to the extent you have. I recently replaced my alternator due to the voltage regulator going bad but saved the old alternator for a project like this. Time to take your skills and knowledge and make a thing out of it. Thank you!

[@DavidPozEnergy]

Your welcome. Your situation is perfect! I would have used an old alternator if I had one lying around.

[@SOLAR-cr5dp]

Great build David! The alternator truely puts out six phases, hence the need for two bridge rectifiers. The six stator windings consist of two sets of 3 wires, i.e. two individual STAR connections however, they are 180 degrees phase-shifted in order to provide you with a waveform (on the DC side of the dc-combined output) that has very little ripple.

[@dwbogardus]

Yes, it would have been better to use the original 12 diodes that were pressed into their original heatsink. No need for the external diode bridges or heatsink. You can still get well over 100 volts DC, and the rated current of the alternator. I've done it before. The filter capacitor is a good idea, and needs to have a rated voltage well above the highest output voltage you ever expect from the alternator, like 200 VDC.

[@dave56ize]

@@dwbogardus My thoughts exactly.

[@altair7001]

The fact that the two windings are out of phase from each other is important to the best performance of the unit. Thanks @SOLAR-cr5dp for the info! Technically, would you agree to say that the two winding sets are at 60 degrees offset from each other, rather than 180 deg ? It would be interesting to see a similar project done with the original diodes! Edit: I see in another post below that the original diodes don't have a high enough voltage rating to be able to use them at 90 volts.

[@hardhead7056]

​@@dwbogardus%100. Reminds me of one of those OVERLY complicated mousetraps..

[@paulhafner9781]

Well done! Congrats on idea to proof!

[@boxbawks]

Man, you do the things I've been talking about for several years; which is recycle materials and think outside of the box to get the best out of them. Anyone that builds self sustainability (even if its just working TOWARDS it) is going in the right direction in my book! SUD'B!!!

[@DormantIdeasNIQ]

only one problem, the experts who already serve this cooked are in the same thinking, thus reinventing the wheel is not that more efficient, + most people will not engage in this much technical ability... and don't get fooled, he spend a massive amount of time and research before he even attempted this contraption and got advice from experts.

[@ryankim3612]

@@DormantIdeasNIQ ….you’re prob not that much fun at parties…?

[@MHLivestreams]

Agreed. Backyard shed engineering is best. I'm wanting to make a little diesel 12v generator now, maybe with a flywheel, try getting max output from minimum revs. It's easy finding unwanted stuff from people to make things from. Great fun, and satisfying.

[@OriginalBtwiceborn]

One improvement I would consider is separating as many components as possible from the engine vibration. Great build

[@hanko456]

Hi Dave thanks for sharing your knowledge with us. I have a lot of fun. And great experience. You splanextion is very clear. Anybody understand very well

[@Jim_One-wl4ke]

Awesome ❤ I sure like to try this off grid backup in case there’s no sun. Thanks

[@jsmith3728]

This is genius. Please do more with this

[@n0ctrnl128]

A tensioner pulley would be a great addition. Keep you from having to torque the belt so tight with that bracket and make it MUCH easier to maintain. Also, putting some high(er) tension springs between the engine and the board would absorb some of your vibrations.

[@markb3146]

I agree on a tensioner but I would source one that is spring loaded.

[@kinzieconrad105]

Wrong

[@DodgyBrothersEngineering]

Wrong way to go. You are adding to the side load of the mounts.

[@taylorboarman7993]

Your a genius, would love to watch more alternator builds.

[@ebptube]

Nice idea and presentation!

[@artman001]

Dave, best diy project so far. You just proved several people wrong who said this wouldn’t work! Please do fuel consumption test at different RPM’s. I recommend rigid mounting the engine and use a ballasted mount, possibly a poured concrete base. Great job!

[@DavidPozEnergy]

Thanks. I wasn't setting out to prove anyone wrong, I just wanted to see if it would work. There are a couple 48V alternators on the market, but they cost more than my whole build.

[@DavidPozEnergy]

Interesting! Now you can share this video link with the Victron engineers and see what they say.

[@D2O2]

@@artman001 They likely didn't understand what you were wanting to do exactly.

[@mr.goldenrod291]

Well done! “It all worked.” I’ve been experimenting with solar systems, batteries, generators, inverters for 15 years and I often state the same phrase (followed by “didn’t start a fire or get electrocuted”.) The frustrating part of this type of experimentation is it shouldn’t be so difficult. There’s too much info that is kept from the masses.

[@GalloPazzesco]

Wow, outstanding. I've watched this three times and have literally taken notes, drawn diagrams, paused along the way ... best class on this type of build for my Lister Peter diesel build I could have hoped for. Been a long time fan of yours David. If I had your hair I could have been President. Subscribed, bell rung, commented, upvoted, liked, shared ... may the algorithm gods smile favorably upon your channel friend.

[@DavidPozEnergy]

Thank you very much. I made improvements in Part 2 and 3 of this project. If you build something with your diesel engine, please send me a link. I'd love to check it out.

[@canadatruth535]

Outstanding build! I am currently working on the same type of system, using a Tesla Turbine to drive the alternator. Thank you so much for proving the electrical concept will work.

[@jjohnston7837]

Love it! I'd definitely like to see how efficient this rig is.

[@deuspax]

This DIY is great!!! you managed to pull from 6.6hp engine a 3kW from a handmade contraption when maxed, which is awesome. PLEASE do the efficiency test, it is quite interesting to find where is the lowest point for

[@TheRainHarvester]

3kW = 2100 HP. So 33% efficient?

[@keithfucious7067]

I watched the entire video. You did everything you were supposed to do so it had to work. I am sure you had some issues along the way we didnt see, thats just the way it goes..Good work!

[@mohamad703]

thank you i like it and many things noticed and to be considered while doing these projects

[@Crash5291]

Interesting indeed! I would thing that the mounts you added would work better if the Engine and alt were on the same mounting surface, it would also make adjusting the belt simpler and eliminate the flex between the motor and alt. Depending on the Alt brand some come with a dyno sheet showing the output vs shaft rpm could be handy in setting up the belt drive ratio. Cheers

[@arnaldofettuccine5227]

I knew it would work, I would like to see the fuel consumption test per gallon. 👍⚡

[@tangoreal9098]

Outstanding! I believe thanks to you I have found a solution for my sailboat.

[@domlecompte2415]

Your patience and taking the time to explain, deserves a Like & Subscribe

[@DavidPozEnergy]

Thanks.

[@juancarlos_2000]

It could be a good option for a range extender on a 48v EV like a side by side. So much fun to watch btw.

[@virian2010]

There is not many people who will take the time it takes to figure out how to pay attention to the details needed to come up with a "48 volt" charging system. I think you did a very good job. You are very good at figuring out how to stay with a project, that would have lot of people just throw up their hands and say "Let someone else do it". plus you are very neat at the way you make your job look like you take a lot of pride in what you do. Good-Job.

[@DavidPozEnergy]

Thank you for the comment, and for watching the video.

[@HOLLIDAYMULTIMEDIA]

Well done. Very useful info. Thanks.

[@hugokappes4077]

I am wanting to something similar to charge my 48 volt solar system with a wind turbine build , a very helpful video thanks ,

[@unknownuser8885]

I've seen in boats where those small frame alternators do not survive well at high duty cycles with near full field output. Particularly with charging large lithium banks where the charge amps remain high for most of the charge cycle as opposed to typical automotive applications where there may be some high initial current but it should taper quickly.. Even some of the large frame alternators that are available get thermally regulated during large charge cycles and or cannot survive at the duty cycle. So if you were to upsize this I would certainly add a regulator or some device to clip field voltage to protect the alternator.

[@DangaRanga]

KZbin randomly recommended this. Absolutely love the project, simply badass. I would be curious to see the temps over a 10-20min full load period. the temps should stabilize in that time. I do car audio stuff and run a custom built externally regulated alt that idles around 230amps and 410amps full load. The hairpin style alternator you have are much more efficient and run cooler than a standard wound alt, they also have better low rpm performance, so you should have a decent range of rpm that will still output full power, but as you mentioned, rpms help cooling. I've abused alts pretty bad to the point of smelling them inside the car driving down the road, they are fairly resilient winding wise, its usually the regulator or rectifier that suffers failure, so your external solution is a better idea. Also, keep an eye on rectifier temps under load as well. If they blow things can get hairy

[@DavidPozEnergy]

Thanks for your comment. I'd love to test out a serious alternator. Do you recommend any?

[@casemodder89]

@@DavidPozEnergy oem alts ARE serious in terms of reliability (non-modified). but you'd need a V2 at 600+cc for an high output alternator. and everything bolted rigid of course. having the engine and alt onna rigid frame and that decoupled from the board would help you build in this state aswell. i didn't expect 3kw output tbh ! nice build ! i'm also curious about the temperatures engine head or better oil, alternator body and rectifier in a long full load test.

[@J_Beazy223]

Hey great video! Its so funny how many of us been thinking of doing this. I myself have been gathering parts for this build for a while. I would be more excited to see it produce the proper AC we use in our houses. That is my goal. Just harness the AC power out of the alternator at 120/240v. Seems redundant to go from AC to DC back to AC in the end. I am trying to skip the middle man and go straight for the AC power. I have seen a few videos of guys dissecting the alternator and adding magnets for stronger flux field. Thanks again!

[@TheBeefSlayer]

I’m also a David and I live the idea of things you can do with alternator!!!! Got several projects in mind.

[@ckiottest5281]

Great test! You should run a fuel economy test on this. I've been looking to do something similar.

[@feedurheadhesaid]

Great video, I'm a subscriber now! Ive been wondering if this could be done cheaply. I have seen commercial products that control alternator voltage for marine 48v systems and also for mobile welding. As far as vibrations go I think mounting the alternator to the engine directly would help loads, right now you've got all sorts of harmonics going on between the belt tension and the rubber motor mounts.

[@pieterviljoen1620]

Well done David !

[@dwayne-7306]

You did a great job, I did the same thing in the mid-80s with the five horse mini bike engine and a regular old 12-volt car alternator self-exciting just to charge car batteries because I didn't have a strong enough battery charger. I think if you slow your RPMs down on your engine you will save more gas and still accomplish the same thing

[@AdamosDad]

I have previously heard about getting high voltage from an automotive alternator, and wondered how it could be possible. But I found an article that explains this very clearly, and offers some guidance if you want to get maximum power. An alternator is designed so that the field (in the rotor) can be driven with 12 VDC from the battery, and produce at least 14 VDC on the stator (through diodes) to charge the battery at idle speed, which is generally about 600-900 RPM. The pulleys and belts usually provide up to 2x RPM boost, or 1200-1800 RPM at idle. However, at maximum engine speed (6000-9000 RPM), the alternator will spin at up to ten times faster than when idling, and the voltage on the stator (with 12V on the field) will then be as much as 10x higher, or as high as 140 VAC (three phase) and nearly 200 VDC through the diodes. A typical 50 amp alternator therefore could produce 200 x 50 = 10 kW or 15 HP, but mechanical limitations such as pulleys, belts, and bearings will in practice limit the power to 2 kW or so. The regulator serves to reduce the field voltage to about 1-2 VDC to produce the proper nominal 13.2 VDC charging voltage. The alternator typically has eight or more poles, so the output frequency may be nearly 1 kHz, and after full wave three phase rectification, will be smooth DC with less than 5% ripple. That DC voltage can be used to power tools with series wound (universal) motors, or most appliances such as modern TVs that use switching regulators. bbs.homeshopmachinist.net/forum/general/2006464-ot-getting-over-120-vac-from-car-alternator

[@ronniepirtlejr2606]

To have less vibrations, you could build a solid metal frame & add rubber bushings ( motor mounts) . Maybe add a spring pulley tensioner? And of course, if you wanted the ultimate smoothness, you would have to replace the Predator with a Honda engine. But that last part is a considerable amount of cost!

[@alext8828]

I liked the 2 thou interference fit with the adapter you made.

[@EF-Electrics]

Loved watching your video, really huge amount of effort and time in making it. well its one way to charge the 48V lithium battery I give you that.

[@thefirstmissinglink]

Maybe a chunk of carpet on the bottom for more vibration dampening. Also maybe a propane conversion. Propane doesn't deteriorate in long-term storage like gas might. And yes the fuel economy test would also be nice. Nice video and I like your attention to detail on your connections.

[@kaboom4679]

Propane will not have the same energy as gasoline , so the motor will not make quite the power it did running on gasoline . It is a viable option and adds flexibility . That said , I would expect the motor to likely stall at peak load . Be fun to test anyway .

[@stazh9118]

Great video! On the capacitor wire sizing: please keep in mind that the capacitor will suck all the current until it's charged (there is tapper as it gets fuller). Then once it's charged only the ripple smoothing current will flow which will be a small amount compared to the output of the alternator. But in the begining, when the cap is empty it acts as a short (since the internal resistance is small). Amazing video considering you said that you have no electrical eng background! 😊

[@jimw7916]

In actual fact .....the capacitor was TOTALLY unnecessary.

[@blg53]

@@jimw7916 I second that. There are plenty of anecdotal evidence that the battery will be conditioned better if the charging current is rippled.

[@cannaroe1213]

@@blg53there is a difference between "lithium-ion charge ripple" and "6-phase rectified DC ripple to the charge controller itself". I dont think the capacitor was unnecessary, a scope would tell you, but they cost >10x more than what this whole build cost.

[@miker2753]

this presentation was very informative and helpful. Have a project I've been putzing with and this knowledge and incite should be very useful. Thank you for being thorough with your explanation on everything.😁