He already tried that, it didn't work

@Eliseo202 he tried without completely isolating the 2nd alternator... they ground through the frame so if they're mounted on the same metal and wired in series then one has a dead short.

Potentiel of the first is 0v because is grounded. Potentiel of the second is +24v. So final voltage between ground 0v and higher potentiel will be 48v. So alternator #2 must be isolate from metal frame ! ❤

This video is a waste of time. davidpoz shows how to do it with a 12v car alt and get 48v 3kw from it. and he link all the parts needed so anybody can do it.

I suggested in the last video either Teflon or nylon bushings isolating one alternator then connecting them in series. I also said that his engine is wayyy too small. As follows: 746 watts = 1 horsepower amps X volts = watts 100 amps X 48 volts = 4,800 watts 4,800 watts / 746 = 6.43 brake horsepower This does not taking into account losses in the belt drive, the, I'm sure, overly generous horsepower ratings of Harbor Freight engines and the need for reserve horsepower to avoid stalling under load and I didn't include, last time, friction loses in the alternator bearings. Judging by the sheer physical size of his engine, I'm guessing maybe 5 or 6 "rated" horsepower. I suggested he get a quality 8 minimum or better yet 10 horse engine and use the above mentioned insulating bushings to finish his project. I haven't finished watching the whole program but judging by his jury rigging the inside of the one alternator, he's in for major disappointment when he smokes the diode bridge in that unit. That alternator housing doesn't offer enough area to sink the heat away from those diodes for what he's going to be asking from them. David Poz has a channel where he took a 12 volt X 212 amp alternator for a Ford truck, removed the stock diodes and regulator, isolated the two discrete sets of three phase field windings, connected them to two separate outboard bridge rectifiers and, with some other peripherals, developed 91 VDC that he fed, @ 40 amps, into a 100 amp Victron MPPT solar charge controller that output a regulated charge to his 48 volt system. This was an experiment for David that worked in principle but didn't pan out. Reason being that a year before, he did a Kw hour per gallon of gas test on his 6,500 watt portable generator driving a 100 amp @ 48 volt charger then did the same test on this project. His big generator got something like 5.3 Kw hours out of a gallon of gas where his new project got just over 4 Kw hours with a much smaller Harbor Freight engine. He had fun building it though.

thank you for your information Sir !

Dude, you REALLY need to do a video on how to make a 48v setup work with minimal modding of alternators!!

@@manoo422 I've never seriously played around with making a 24 or 48 volt output alternator from a 12V automotive alternator, but playing around with them I did see that without a load (12V battery) they would produce over 50 volts. In my (long) response, I did make a typo when I talked about the diode trio provided 24V to the regulator. It should have read 14V. Everything else was correct, in theory. I guess I needed an energy crisis (other than the gas shortages back in the '70's), and could have gotten a jump start on alternative energy sources! Now I just have to sit back and watch the fun...one other neglected comment of mine - some automotive alternators now produce over 200 amps, although not continuously. Audi has gone one step further, and is making water cooled alternators!

@@DoctoreE644 48v systems are now part of many peoples home battery setups. The major problem is how to remain viable during winter months by producing fuel in the summer and storing it until winter. Whether thats with Hydrogen or Ethanol or something else its likely to end up with an engine and a generator for which alternators are a very good candidate. If you have any useful information/experience on achieving this you should pass it on now to those who need it or it will simply be lost. We are all judged by what we leave behind...

@@manoo422 thanks for your comments, and your concern for the future of off-grid power generation. Even though alternator tech has advanced considerably since I was in the business, the theory of how they work is still the same. The stator windings in the alternator body produce 3-phase electricity in a wye or delta configuration. The older ones use the wye, recognizable by three wires going to the rectifiers, and newer ones are delta wound and all six wire ends terminating in pairs at the diodes (1 or two negative and positive diodes for each phase) in the positive and negative rectifier banks, creating a pure DC output. The rectifier banks are normally attached to the alternator body, so the internal fan cools the rectifier assemblies, which are heat sinks. It is all designed as a unit, and are meant to run for years in the less than optimal conditions under the hood of a car. These rectifier banks are well-engineered, and are about the best bet for long life. No need to spend money on re-engineering the alternator. Now for the built-in regulators that are in most modern alternators. It's pretty obvious that they are not likely to survive 24 or 48 voltages, so they need to be removed. Older alternators have a diode trio of small diodes that are attached to the three (or 6) stator leads at the main rectifier banks. This diode trio supplies rectified DC to the regulator, and then the regulator varies its output voltage, through the rotor coil and the brushes, to ground. It's possible that the voltage to the regulator is only supplied through an ignition source, but that is something that will have to be diagnosed by the DIYer. Just removing the regulator should be all that is necessary to remove any supply source. As far as the brushes, they are usually contained in their own housing. One screw that holds the assembly to the alternator is usually a ground connection, and can be determined with an ohm meter. The other brush goes to the regulator, and once the regulator is removed, a wire can be attached for a remote 12V source, supplied by the DIYer. I wouldn't recommend running the rotor voltage at other than 12V, as it is designed to run at the normal 14V of the original alternator. After all, the rotor is only a variable magnet, and to convert it to 48 volts would require disassembly, which is a big chore, requiring shaft removal (using a hydraulic press) and rewinding the coil. A remote 12V regulator is eaily sourced. Most rotors only use about 5 amps, but newer models may be more. Best to check with an ohm meter and use Ohms Law to determine amperage draw, and purchase a regulator with an amp rating double that of the rotor draw. No sense in running the regulator at full capacity. That would jeopardize the life of the regulator! About the only other thing I can think of, is make sure the alternator is spinning in the proper direction! An alternator will produce electricity in either rotation, but the internal fan is most efficient in the designed rotation. The fan pulls cooling air through the fins on the outside of the alternator, and over the stator coils and the rectifier cooling fins, and out the back cover. Which reminds me, put the outer plastic cover back onto the alternator, as it is all designed to keep the alternator as cool as designed. And the designers spent a lot of time and engineering to do just that! Don't throw all the money of that engineering away by modifying the original alternator. They know a lot more than us tinkerers!! Please feel free to pass this along to anyone interested in using an automotive alternator to charge an off-grid electrical system. It is only practical operating information, and there are sure to be exceptions to what I've written. I've seen a lot of folks who cannibalized an alternator when they didn't need to. As long as the right-sized cables are attached directly to the alternator case and the output terminal and to the battery conttol equipment, y'all should be good to go. One other thought - in case the alternator runs quite hot (it's best to monitor it in the testing stage), a safety circuit can easily be hooked up, by using a dryer temperature switch (125C or 257F) wired in series between the regulator and the rotor input. Mount it flush to a flat part of the alternator. Temperature switches can also be found in electric tools and appliances, as a flat sensor device hooked into motor power lead and attached to the motor. Just make sure that the temp rating doesn't exceed 250° F. Good luck!!

True the reguator might bur out And yes if the alternators are out of sync then you lose voltage (can only be seen with an oscilloscope) A capacitor over eatch alternators dc output will help I'm not sure if the 2 regulators in series will like this If the 2nd alternators doesn't start it will get a positive voltage on its "floating ground" and a negative voltage on its positive output

I would use 2 alternators with external regulators And use an extra beafy external regulator Basically what he did but with a upgraded regulator Maybe it's posible to wire the rotors in series?

A pair of capacitors seems like a much easier and cheaper solution than a syncrometer.

Awesome awesome the teacher

Yea, I got them up to 70amps now which is less than I hoped for but more than I really need.

iron core tranny dont work well with the high freq output of the alternator my friend

Alternators don't actually output DC... they output rectified 3-phase AC, it only becomes real DC after being filtered... and with 2 of them in series without any capacitors to filter out the rectified pulses, it will be very inefficient... because the two alternators output pulses are not synchronous.

Thats why you connect a battery there wired to each.. in your case at 24v you need 2 series batteries on each leg..then series all of them to reach the 48v..

I pulled them out. The 10,000lb battery bank this goes to works as the best capacitor to smooth out current you could ever ask for.

​@@Trialnerror Yeah, your load will get good clean DC, but the batteries will see ripple voltage during charging. That ripple voltage may or may not have an impact on the batteries, or BMS depending on chemistry. It's probably fine, but worth checking into either way if you aren't planning to smooth out that ripple. Cheers.

Having some ripple on dc for charging lead acids are better than straight dc. Actually none of the battery chemistries care aslong as the peak current is not above their rated charge current & the voltage is not going into negative.

Thanks and thank you for checking it out!

Yea...if you have wind. We don't in NH.

Hello from your southern NH neighbor that you wish was a bit more normal :). Different company (why they decided to pick up that name is beyond me).

Let's assume it is expensive electricity. Designed for use when expensive electricity is much better than no electricity. ;) Not to mention how un-green it is.

@@kevinsellsit5584 Un-green is the best.

What you just wrote is impossible. If you leave the alternators alone, the output of either will be DC. You cannot use DC on a transformer period.

@@elser2utube the problem with you ending on your period is that it's not true. The first transformer ever made was DC. It needs a capacitor to pulse the energy at a particular rate. Energy plus vibration creates a frequency. "If you want to understand the nature of the mysteries of the universe you must think in terms of energy, vibration and frequency. " - Nikola Tesla.

@@captainKedger With all due respect. You didnt mention a capacitor in your initial "All you had to do instructions". However, If you put a capacitor on the unmodified output of one or two alternators, in any configuration, all you are going to end up with is a better DC "waveform" on the transformer primary due to filtering or buffering. This would be accompanied by nothing on the transformer output, apart from useless spikes when you disconnect to troubleshoot, and heat generation in the grossly inefficient resistive heater that was just custom wound. Besides, if you wanted to "correct" the voltage via a transformer, it would only make sense to remove the alternator output bridge (same modification done in this case) and route the AC output of the alternator to a three phase transformer primary, then rectify the output.

@@elser2utube you have a couple of good points there. I live on a boat so I find 12volt DC current to be much more useful. I often forget most people live in houses.

@@elser2utube they put out high freq so iron core tranny will still be a heater lol

That didnt come out right.. but yea…

I have. I changed the pulley and am making on average 35 amps @50v burning .4 gallons per hour so I'm making just shy of 4kw per gallon.

@@Trialnerror That’s about £1.50 a kWh for those in the UK

@@Trialnerror Thanks for checking the fuel efficiency. Your setup is very compact and nice. I did a great job with it.

I watched another video that used a timing belt style cog belt. Low friction with no slippage.