Trying (and failing) to build a 48v DC Generator for Off-Grid Backup
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- Опубліковано 27 вер 2024
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I think that this has been mentioned previously, The alternators will work in the way you have them set up. However, you have to isolate the second alternator from the chassis. Due to the chassis being the ground for the First alternator. Best way would be to find a way to isolate both the alternators from the chassis and each other. In the way that you have is wired/set up, the first alternator is shorted to itself through the second alternator case because it is connected to the frame and by default the case of the first alternator.
This is just what is needed for partial rv backup. Operates the ac and stuff perfectly. ua-cam.com/users/postUgkxOTeIs0vv4_9B5hsmnLsk9r930uDQLu_Y is quieter than my rv generator. Only suggestion is that it needs a fuel shutoff valve. So it is easier to store.
One of those two spade terminals is a voltage sense wire that allows you to measure voltage at the battery instead of the alternator to account for voltage drop due to resistance . It is internally connected with a high value resistor so it will sense at the output terminal without the sense wire on since that would be a common and horrible problem. Use two equal value resistors to create a 2:1 voltage divider. Connect your 1/2 voltage signal to the sense terminal. 24v become 12v so the alternator regulator sends more power to the rotor until the sense wire reads 24v. Output will be 48v. In theory you will need 2x rpm, In practice maybe not that much. Also, you might as well go get at least the 420 predator. Alternators are tough but not efficient.
He couldve just bought one off aliexpress... " Range extender fully automatic 5kw "
Neodymium magnet generators are much smaller and super efficient when compared to those car alternators.
@@mihkusI have a remote cabin and 20 years ago I got a 48v inverter charger. I thought about making one of these or even getting a 24 v alternator with a 24-48 converter. Instead I got a Honda that has an eco throttle. The inefficiency of converting 120 vac to 48v with the Honda probably offsets doing it directly with something like this. Also I can control the charge rate and run time of the Honda through the inverter..
Why not use regular car altinator with external regulator set to 48volts?
Awesome content
Love all the hard work
My 2 cents :
The entire unit I’d put it on a metal dolly (mobile unit camping or off grid )
The pedifile motor change it to run off propane, remove the governor, a racing carb better out put at low RPM save even more fuel
To calm the vibration platform to frame weld used valve springs
To ground use heavy long welding ground clamp with magnet
In an off grid system get those copper rods cut in quarters, point and into the ground or clamp to a bumper bracket (member 2 separate grounds)
* one motor . . . 2 alts one set to do refrigeration / or ice machine to prolong cooling and lighting
Second pair of alts (can disengage from main motor) used as a back up or power washer and a shop for tools maintenance or even build a house, stable, ranch, mill wood
I got my idea from Brazil they got this down the power companies keep this hush hush
I made a 48v generator using an 8kw 48 volt motor I got from amazon a few years ago. I used a chain and sprockets and with a few switches I was able to power the motor so it started the gas engine. after the engine was running I would switch off the battery and then use the motor as a generator. The motor was only 400 bucks brand new.
I am assuming that you bought a 40V DC motor?? Which implies the use of a commutator inside the motor, in other words like an older DC automotive generator?
Or am I missing something?
@@carld3184 Yes it was a 48v dc brushed motor. since then I changed over to a dual engine setup with two 24v dc motors so I have two separate systems just in case one breaks down.
If you ever build a version 2 and wanted to make it less top heavy, turning the engine 90 degrees and having two pulleys on the crank with two belts running an alternator each side of the engine should work without additional tensioner pulleys. You mentioned decreasing the rpm, but it needs to be high enough to provide sufficient cooling when producing 100 amps as the alternators could overheat. I've thought about the same type of project, I have a cheap 100 amp DC inverter welder that could be used on my generator. The off load voltage is about 70v and can be finely adjusted with the welding current knob. Inverter technology is surprisingly efficient, and it would be a very cheap option. In the UK gasoline is very expensive, Amazon sell cheap natural/propane gas conversion kits for clones of the Honda GX200 engine that replace the Carburetor, providing three fuel options. I bought one for only £25 from Amazon in the UK. Great option for a generator that hardly gets used as no gasoline to turn bad, it will just work when needed! If cheap gas is not important, a propane cylinder will sit for years before it is used. All food for thought!
Buthane and propane gas 🎉in EU and GB costs about double the cost of liquid fuels like gasoline or diesel per kilo and energy equivalent so gets pricy per kw compared to liquid fuels .I don't know cost for propane and buthane gas in USA but natural gas might be cheap enough on direct pipe feeds but I don't know if there is natural gas bottles😅😢
Thanks for doing this. I really enjoy your channel and humor.
I'm also stuck with running an AC gas genny to charge my off grid system in the winter. I think that I've exhausted my searching for a reasonably priced commercially produced DC battery charging generator. I run a 5 kw AC generator between 70 to 125 hours annually. I look at this cost of this operation as reasonable. I don't know enough electrical engineering to build my own DC charging unit. In my mind, as a sort of parallel thought, I rationalize that I drive a 14 mpg 4x4 truck for about 2K miles per year in the deep snow and a 48 mpg Prius the rest of the year. The large inefficiency and expense of my winter transportation is necessary and reasonable. but please keep doing Trial N' Error and I'm delighted to watch.
DavidPoz just built something like this. He used a treadmill DC motor that produced over 100V but lower amps, attached that to an MPPT charge controller to output 48v and 14 ish amps.
Another issue you have is that most Automotive engines have an 8-11 inch crankshaft pulley. That coupled with a 3ish inch alternator pulley will give you your desired RPM and allow you to use less power to drive the alternators.
power needed to drive the alternators will remain the same.. ideally you want to run the engine in it's peak torque/efficiency RPM range
@@paulkaygmailcom power to drive the alternator goes up as demand/output goes up. It could be anywhere from 1-5 HP PER alternator. There's two and these are 24V High Output. Which means the load on the engine could be even more. We could be looking at using upto 15 HP to run these at high load.
@@cliffweatherbee6914 i doubt the 24v/100a rating of those old delco alts.. better off using the large frame hairpin denso units
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These are the numbers from 12 to 48 volts - each HP input into an altenator generates 385 watts - at 120 volts up to 22000 volts DC each HP generates 416 watts -
There is about a 25% loss with a solid state switcher charger and 40% or more with transformer chargers - when converting AC to DC low voltage -
Those numbers have been known a long long time - I worked as an SCR electrican in the off shore oil fields for decades -
Also when farmers had farm home light plants that were 32 volts through out the country - off grid living had been mastered since 1890 to 1970 or so - my grand father worked on all those rural home light plants & the lead acid and iron battery's - those lead acid battery's were good for 40 to 60 yrs in many cases lol -
I haven't seen your entire video - as for those engines 2700 RPMs is there max power curve - the alternator's on cars and trucks can give full out put at 2500 RPMs -
A DC system with a direct mounted generator is about 20% more efficient then going from 120 AC to 48v DC or lower -
You would come out better using a diesel engine than a gas engine in the long run - you can get them on eBay or Amazon for a little more than a gas engine -
Also the altenator's might be rated at 100 amps - but that rating is often the same as the rating of small potable AC generators - a generator might say 4000 watts that's the KVA rating for 10 seconds - if the 4000 watt generator has a 7 HP motor that's 7hp × 416 watts so the generator is a 2830 watt. Generator -
If you attempt to draw the name plate amperage off many altenator's they soon burn the diodes out -
As a rule if you can't hold your hand on a altenator for more than 10 seconds it's to hot -
Most car and pickup truck altenator's over heat at around 450 watts - for most truck altenator's it's at about 750 watts or so -
If a car altenator says 120 amps that for 1 minute - not continues - Blamor makes altenator's with high end diodes that can handle high temperatures of high out put -
For each belt drive there will be a 1/2 HP loss or 190 watts to belt friction -
I don't know what your final conclusion is on your set up - if you decide to manually control the altenator voltage use a 100 ohm 100 watt variable reastat - Amazon has them you can manually control the field voltages - but a MPPT from 24 to 48 volts is a better choice - we used air cooled diesel engines set on altenator'sset up on un maned platforms to back up communicationsv, fog horns and nav aid system - when the solar panels were unable to maintain voltage - the diesel air cooled engines were automatic electric start and shut down that we made up -
.
Great video and impressive DIY project! I had a thought regarding the challenge with the 24v alternators. Instead of wiring the alternators in series directly, what if you wire each alternator to its own 24v battery or capacitor in parallel? Once charged, you can then connect the two batteries or capacitors in series to achieve the desired 48v output. This approach might simplify the setup and ensure efficient charging without interference. Just a suggestion! Keep up the fantastic work, and I'm looking forward to the next video!
When you try modifying them to just put out 48V each and wire them in parallel, you might run into the diodes built in not being rated for enough voltage, but unlikely. Running your own circuit to drive the field coils is going to work, I know plenty of people that do that. Some use a DC motor speed controller to set the coil current. And that works, but you will need to get it some feed back so it can regulate voltage and not just current out of the alternator. Anyway, I wish you good luck
For what it's worth, great idea, back in the early days of YT you would see projects like this, mostly riding mowers converted to welders. Another guy on YT ran into a similar issue doing this with a Bike, he used a separate DC input to excite the regulator.
I would simply isolate the grounds on each alternator, get the power from both units and figure it out post. Going to check your next vid and see what you did...and maybe see if you got a heater.
I like the way you looked into the alternator construction and the explanation , so grateful for your video I would to see it again much appreciated many thanks .
Wouldn't it be easier to output the alternators to two separate 24 volt batteries and then pull your 48 volts from the two batteries run in series? That would allow you you use your current build, which looks nice by the way, and keep the alternators stock so they would still be easy to replace if they fail. Which they eventually will.
The negatives of both 24v sets would be tied to ground. Can't be connected in series or they short.
@@jmaus2k, or u could use a diode on the power wire to the batteries from the alternators. To keep current flowing one way, & not backwards. If u put a diode on each wire going to the alternators ground & hot it could work. Or I wonder if he could just spin the crap out of one of the alternators & get 48v.
See what the max rpm for the engine they are meant to be on is, get an extended warranty on the alternators, then when ur burn em out get a new one for free.
Take one alternator apart and insulate the negative from its body so it can be connected to the first alternator’s positive.it’s voltage regulator should follow the same path .
You could have set up two 24 volt batteries with each alternator charging and voltage sensing off of a one of the batts. Then rig the series output of the batteries to your system.
I have done this many times in the past. And have built these all you need is two 100 a bridge rectifiers. Hook up a ground wire to each rectifier on the incoming 3-phase AC terminal doesn't matter which one. And then Bridge the other two incoming AC terminals together with a link . And then hook a positive wire to the to link AC terminals from each individual alternator. This will give you two separate negatives and 2 separate positives totally isolated from the system that you can then run the dc outputs in a series to create your 48 volts. I would also recommend putting a 100-amp breaker on each rectifier that way if the rectifier shorts or goes bad it doesn't take out the system it just trips the breaker
AC to DC Bridge rectifier in also be used as dc-to-dc isolators. As the same and you can use these to charge for 12 volt batteries independently isolated even though they're all hooked up in series for 48 volts
I always put 100 amp breaker in between everything as well. that way in case a rectifier blows it doesn't take out the system it just trips the breaker
I have seen people talking about getting 100v or so out of modified alternators that seems like a decent idea maybe just with an arduino or something to control it I don't remember how it was done I think just by bypassing any regular but it was obvious unregulated so if you could control the voltage to the field windings you could probably dial it in and it would be cool to have current reading and it could very the voltage to limit current appropriately
you could use externally regulated alternators (or convert those to externally regulated) the more voltage you put to your windings the more voltage output it gives, using a custom rolled AVR or finding a 48V AVR and as i said converting those alts to externally regulated, then pushing the whole 48v (or i guess 50V in this case) through a set of full bridge rectifiers to get your full power output, add some caps and you can smooth any output ripple and get clean output power to what you are trying to charge
Exactly, get two large case Ford 100amp externally regulated alternators. I have welded off these for years. You just need to pony up $$$$ for a 48 volt regulator. You can try amptech alternator for one of their regulators, but think they may only do 12/24 volt.
Go look at what David Poz did. To bad you guys didn't collaborate. His design worked electrically, very cool. His mechanical setup not so great but he was trying to get 48v down and dirty... Cheap.
Tesla is going to a 48v system for accessories, lighting etc. Ditching 12v. Hopefully as that makes 48V stuff will become more available.
I imagine the day when I'm running solar into a 48 VDC battery bank and then feeding it to the house directly to power 48V HVAC, lighting, and other devices. Meaning no inverter or a very small one to handle legacy 120V appliances. I except to see Marine and RV applications move to 48V.
I can dream right?
When I was in the Navy Seabed, our Chevy blazers and 1 ton pickups had dual 12 volt alternators wired in series to produce 24 volts to charge the 24 volt starting system and for NATO compliance. The alternators were 100 amp, 12 volt, ISLOATED GROUND units. They were NOT case GROUND. The vehicle ran on 12 volt except the starter and military radios. Each alternator was wired to a paint of 6TN batteries and one was wired to the main harness in the vehicle. The wiring the the vehicle was the same as any square body Chevy from the mid 80's.
Just to toss this out there I have a 12 volt set up i built myself that works really nice Im very happy with it. If you want 48 volts your going to need a 48 volt brushless turbine or alternator (permanent magnet) some where in the 2000 watts area but that will only give you about 40 amps + or - 5 depending on efficiency. What type of batteries you have is going to play in a factor or 2 as well. I run a hybrid AGM and Li-Ion system myself but 12 / 15.8 volts. That 50 amp breaker you have on this build will fail they are junk best off to use a ANL fuse.
"damn good project! you got everyone chiming in!
im watching too!!
You can adjust the field in GM Delco alternators up to about 90 volts. reg. screwdriver through the back fins to field screw.
I wish I had the time to try most of the stuff you have done... Eventually I will. Love your channel.
I make failing look fun LMAO. Thanks for watching Orange Brother.
i built sort of the same but used an alternator off a bmw, it is rated at 180 amp and 12 vols. used a car tensioner with the belts. even with 5 horsepower it will start cars with a dead battery
This would have been simpler with a single 12v 100a alternator. Remove the regulator so that you have direct access to the three AC phases and to the rotor brush connections. The alternator is designed to produce 12V below idle rpm with 12V on the rotor and, without the internal regulator, it will output volts in proportion to rotation speed. A typical alternator might be geared to run at 3x crank speed so will give over 12V at 3x600 crank rpm (say). so if you gear it to run at 6000 alternator rpm you will be getting close to your target output voltage with 12V on the rotor. You then need a bit of simple electronics to adjust the rotor volts to give the required output volts. An external 3 phase rectifier is also needed - I wouldn't trust the internal rectifier to work at the higher voltage.
Good idea
Here is how the army used to create 24v charging from 2-12v alternators they used divorce (floating) ground alternators to start with... You will need a positive battery connection for each alternator in the stack for you example each 24vdc alternator needs a 24v battery connection. Connected alternator 1 ground to chassis ground, alternator 1 positive to 24v battery connection, next the alternator 2 ground connects to alternator 1 positive (24-48 battery negative) connect the alternator 2 positive to the 24-48 battery positive.
Another option is to run the alternators in parallel powering a 24vdc to 48vdc converter to reach your final charge voltage
You could simplify things greatly by leaving the alternators alone and charging your 48 volt battery bank as two groups of 24 volt banks.
Now that you have done the hard work, all that is left is to do proper wiring.
Why do you have to ground them to the chassis? Keep them separate and floating (insulated/isolated).
Use a 24v battery in parallel with each alternator as a buffer and wire each circuit accordingly.
Then wire the two circuits in series and if you are super paranoid put a heavy duty (>100A) diode between them to isolate the battery sensor wire.
That should do it in a way that they won't get any phase issues or efficiency losses.
The main reason that vehicles use a ground is to halve the amount of wiring needed and make it easy to complete circuits.
If you really have to ground it then ground the lower alternator as per usual and float the upper (24-48v) circuit.
Cheers.
You could also add a heavy duty dual battery balancer unit to make sure they don't get out of hand...
for a 48volt battery back you will need close to 57Volts potential to properly charge it. Regarding efficiency, power transfer etc.. You need about a 2 HP engine to drive a 1KW generator so your choice of a 7.5HP engine to drive your generator was spot on; However your choice to use automotive 24V alternators was a bad choice as they are terribly inefficient as compared to a PMA alternator.
I seen a video where they used 5" pulleys 1:1 and it was perfect voltage at Low RPM 2500
WITH 100A current.
Easy as mounting 1unit to a plastic isolator. the + from the grounded unit on the frame to the case of the isolated unit, the + on the isolated now is 48vdc. wire the voltage regulator for each unit only to its self. 24 +24 = 48 gust like 2 24v battery's = 48v.
Alternators will work spinning either direction. The only problem is the cooling fan, but you can get aftermarket fan blades that will cool the alternator in reverse...
Maybe….. add a charge controller to the mix? It’ll take the 24v x2 and spit out the voltage you need. Sub’d
Great vid & not a bad build effort mate, a fun & handy project. I believe it is possible to control ur rotor voltage separately to boost ur output voltage, you could then use a MPPT controller to regulate ur output voltage to a safe & stable set output limit to ur batteries regardless of rpm.
I have serious doubts that motor will have enough power to run 2 x 100A alternators which would be around 5kw total, I think 1 alternator could make that engine work hard enough if modified to output a higher voltage, and then it could be directly coupled also increasing efficiency. I’m guessing 2-3kw will probably pull it up, & u could possibly need to consider extra cooling for the alternator also.
If the problem is to charge a 48v nominal battery bank then I would probably suggest a different approach. I'd get a 240v primary to 120v secondary AC transformer. Feed 120v from your generator to the primary (240v) side which will give you 60v on the secondary (120v) side. You can then pretty easily convert the 60v AC to DC with a bridge rectifier and smoothing capacitor. You'll drop a few volts through the rectifiers which will be about right for charging a 48v battery bank.
problem with that is you have no current regulation, you dump 60V onto bus that say is at 53v because the batteries at at a lower state of charge you pull hundreds of amps out of that transformer. if the transformer, generator, and batteries are not all capable of handling that something will break. you would have to hack the generator voltage regulator to correct this. also high amp low voltage transformer are not super common so they are expensive or you would have to use and oversized say 480 to 240 transformer. where the secondary can handle hundreds of amps so like 25kva transformer for like 6kva of power which is also expensive. plus you still have core and copper losses in the transformer to deal with.
@@orbitONhigh My issue is not with his approach but the use of automotive alternators. Those 100-amp alternators are really only designed around a 30% or so duty cycle. What he wants is 100% duty cycle or 48v@100a for days on end. In order to do that reliably he'd probably need 3 or 4 alternators. If he is adamant about greatest efficiency and generating 48-60v directly I would recommend customizing and controlling a genset itself similar to what he is doing with the alternators. It wouldn't be any less expensive than what he's currently doing but it would likely be more reliable. As far as using an AC step-down transformer goes the goal for me would be to create a reliable 60V-ish DC bus using mostly commodity parts. I would never try to charge directly off the DC bus without using a charger/controller. You are correct that he would likely need to get a 25KVA transformer in order for the windings to handle 100-amps at 60v. The good news is you can get a used 240/480v to 120/240v NEMA 3R dry-type transformer for around $500 if you don't mind taking your time and picking it up yourself. As far as 100s of amps goes you are only ever going to pull what the generator can provide before popping it's own over-current protection. For safety I would still breaker the secondary side of the transformer just to limit overall power through it. Efficiency wise you are going to be 95% efficient through a common 60hz AC transformer. The goal with my approach was to be as robust and reliable as possible using mostly commoditized off-the-shelf components. Even with the 25KVA transformer if it does fail for whatever reason you can buy another one and just wire it in since they're a super-common transformer. With a customized alternator setup or a re-wired genset if that fails you are just kind of done. There is no driving somewhere, picking something up, and simply slapping it back in where the old one was. In all likelihood you will get years if not decades of service life out of a transformer while being able to move to more efficient gensets at any time. The input for the Transformer could just be a weatherized L6-30 connector so you could hot-swap the generator whenever you want.
If he allready has a 110v generator, why not just get a 48 volt charge controller? And use the existing generator.
@@KevinSmith-os5yz he's got one but it's only 2kw and he wants 5kw. He also wants to remove losses from the various inverters in the setup and go directly to the DC bus for his battery chargers to use
A 48 Volt conversion cool the see it would also make a cleaner install😎
isolate grounds, 2 battery banks @24v each so each bank is charged independent from the other. with them in series you would still get 48v
The PMA produces 3,500 watts at 2700 RPM. The diesel runs at 3,000 RPM maximum. Running 2,000 RPM it will consume about 0.25 gal/h. Running at 2,000 RPM the PMA will produce around 2,500 watts. So around 10 Kilowatts per gallon of Veggie-Oil with a 30% gasoline blend for the winter. Gasoline is need as a solvent to thin the viscosity and prevent gelling. Summer blends are around 10%. Although these PMA's can out put 3,500+ watts it is not advisable to do so., as the small motor would struggle at peak output. These numbers are not set in stone and do change a little, We need to take into account the losses of the AC to DC to DC conversion and whether or not the batteries need all the power the PMA is producing. The Midnite classic determines the charge need. In case your wondering the cost of the winter blend is about 5 cents per kilowatt hour. The electric grid rate in our area is 17.4 cents per kilowatt hour.
A cheap Chinese dc generator head unit? They make belt driven units that would eliminate all the fuss. Great idea and video.
It's not so difficult, but I wouldn't use 24 volt truck alternators for this but rather a strong (4 -7kw) permanent magnet hub motor from an electric scooter or E-Bike.
I did do this on a slow running diesel 1 cylinder (Hatz diesel) and got amazing efficiency out of this 35yo engine, almost 28% while charging the LiFePo4 48vdc batteries, place a capable 3 phase rectifier between the 3 phase wires of the hub motor and this will get you a nice 48vdc output for your batteries.
You have to mate the engine speed and the hub motor speed to get maximum output and efficiency, my hub motor runs 600rpm and my engine speed is 1400rpm, all belt driven, output about 2200watt, but I use a 3000 watt MXUS hub motor only.
I'm planning to use a 5kw hub motor in the future to get a 3000watt continues output at 1700~ish engine rpm, this would be the most efficient I think.
14:25 Words to live by!
Your commentary had me laughing through this whole video. 😂
I am half way into the video and wondering how you are going to put them in series when you grounded them together
The issues I'm seeing are when you increase output you are going to probably change the rectifier due to power/heat dissipation (possible that voltage may exceed components design specification.)
Also may need to think about a soft start circuit, to prevent engine stalling when load first applied and for starting the engine.
I believe that you will need to run in parallel to achieve the current output. (This may also cause issues balancing the load, but not 100% sure.)
It would be worth contacting a rewind/ reconditioning centre.
As they may have access to the 48v rated electric components which will reduce work, and save having to design your own circuits (ie rectifier and voltage regulator)
Bypass/remove the diode packs go to an external rectifier and run them full field at 12v into a 120v max MPPT charge controller.. easy peasy.. heat only gets generated with wattage.
I died at the Chris Hanson joke.
Instead of all the measurements to mount the motor, use some tape, trim to the mounting surface of the motor, punch out holes. Then put the tape (this time measured) to the rails. Drill the hole punch out and done. Saves a few minutes AND is a bit more accurate than being off a 16th or more.
Nice design.
just use a 120vac or 240vac AC generator, rectify it to DC and send it into a Midnite charge controller (Hawkes Bay would work great), park the PPT. Thats the easiest way to have reliable DC generator that is careful about charging your batteries. Ive used a DC genset on my batteries for the last 15 years and works great. I prefer to custom build the alternator from scratch.
Well done, dude!
So I actually sell a preconveted alternator but I dont set them up to be 48v alternator. Instead feed a solar controller at 100vdc. My recommended set up for customers is run a all in one inverter growatt is recommended. Then the inverter can deal with charge and discharge along with bypassing the battery during usage. My kits $400 ready to bolt on and I rate them at 80a but honestly 120a isnt very hard one part swap needed but the growatts dont like more than 100a and 80 at idle works out to 95-100 driving. Feel free to ask questions some stuff I'd be willing to share not publicly if you want help converting yours
Also your hp to kw math is wrong it takes about 18hp to make this work at 100a in my system
about 9 minutes in here, you most definitely can run an alternator "backward" there are universal vane-type fans available for them, as for wiring them in series yeah it was done on the 1980s GM CUCV trucks used by the ARMY but I'd recommend removing the internal regulators and running an external that will let you push to voltage up to your 48-volt charging voltage. also don't forget that incandescent "IDIOT LAMP" is a critical part of the charging system.
you could use permanent magnets motors from fitness track or how you say it
The easiest way to charge the 48Volt battery bank is to take the 110volt output from your existing generator into a bridge rectifier and feed into the input of the Midnite classic charge controller that you already have 🤔
Seen alternators in series first time
You could modify a normal alternator with a custom voltage regulator to output 48 volt dc
Also, you didn't need to tear the alternator apart. You just needed to rectify the feed to the sense circuit... or split your batteries into 4 banks with an intelligent or manual switch. You could have banks A-B charging separately, while banks C-D are bridged in series for supply... and vice versa. This could be handled by a cheap 48v BMS... costs around $60.
an alternator is suppost to run steady see discription on alternators just at ca 60%
I wanted to build a 36v battery charger for my two 36 v trolling motors. (our dock is built that parallel parking sometimes is a must) I found on line a unit that changes 12v to 36v. A similar one must exist for 48v
1) on one alternator just remove the case ground on diode Bank. Hook this electrical diode ground to other alternator positive
2) just electrically isolate whole alternator case. Then then hook this case to other alternator positive.
Bingo
Treadmill motor will work as well. I’ve seen a few UA-cam videos on guys getting thrown away treadmills and making it work.
You have two alternators putting out 12 yes
Take the alternator's apart get the regulator and everything out of the inside of the alternator bring the three leads out of the alternator now you have three-phase 125 volts coming from each wire out of the alternator without the regulator in their stepping it down to 12 v
I knew what your problem would be BEFORE you even tried to set it up. Have you tried to set a single alternator up for a 48 volt output yet? The diode pack may be an issue because those are high current diodes and they may have a peak reverse voltage rating of only 50 volts which will cut it too close for the diodes and more than likely it will be exceeded with voltage peaks especially when it's in an open connection situation. Another thing is you really need a charging voltage of 57.7 if you're using flooded lead acid batteries for a 48 volt system and this voltage will vary depending on the types of batteries you are using but regardless you will probably exceed the diode packs peak reverse voltage. The last hurdle is a way to regulate the alternator once you solve the other issues. It is workable but it may take some thinking outside the box.
very easy way to do this is ac generator 110v feed ac into bridge rectifier then into the solar input of an mppt controller this will do the rest and is prob the most efficient way to do it
Thanks I suspected this issue I would charge 2 battery banks of 24 volts and then series the battery banks would be my logic preference but would love to see your 48 volt solution.
In marine diesel normal 12volt alternators can't supply rated power for very long they heat up and basically go to 13 volts and low amp slow charge. Proper marine types take longer to heat up and step down in stages but power will go down to low volts and low amps .Alternators to give ,100 amps continuous at 12 volts have to be top end bigger more costly types . I assume same for 24 volts alternators
Normal v belts with high drag nearly always slip so serpentine belt or chain is the normal solutions
The gasoline engine needs to go more like 2x faster than alternators RPM as it is awful low end torque so needs high RPM to work correctly is my best advise but suspect it's still too small .Mostarine diesel generators are twice the power in watts than the generators demands where continuous several day demands are made .In those cases the generators or alternators need to run at 2 times diesel engine RPM to make usefull amps and volts due to slow RPM high torque nature of diesel engines .EG why diesel engines are the majority in higher than 6 kw electric in generator production
I suggest single pot 10 hp 7.5kw diesel air-cooled l100 yanmar or similar as minimum preferably 10 kw to give 5 kw power output at 50 volts and 100 amps
DIY plans exist for 12 inch diameter home brew 50 volt wind generator with higher effency than alternators and are not to difficult to make and fairly cheap .That would strain the engine less I suspect and allow the gasoline 7.5 hp to work
it would be fairly simple to just take an old alternator, the Chrysler ones with the floating field winding comes to mind, and just build a regulator to give you 48 volts out of it. The old analog/mechanical regulators could be adjusted, probably even up to 48 volts (but that might require some internal tweaking).
I think the windings inside the regulator should easily be able to handle the 48 volts (as a single thickness of electrical tape is good for over 400 volts).
oh, you could also take a solid state regulator and bias up its ground to push a bunch higher voltage out of it by forward biasing silicon diodes to it which gives you a .7v bump for each one.
Couldn’t you use rectifiers and then join them up afterwards?
Should have just gone with a 240v generator like I have. It cost me an AR-15 to start with and I have a $20 propane conversion kit on the way.
Can you get a positive ground 24v alternator? Then you could have one of the negative ground and positive ground to give you 48V. You should be able to rewire the one you have as a positive ground, but might require mounting the regulator outside the alternator chassis.
That is how she goes. It's always exciting and looks great on paper, buy when you put the foot down and you are actually building it. You will eventually arrive at the speed bump that makes you doubt your abilities. The best part? You have accumulated knowledge that NOBODY can bestow on you. Make 999 bad light bulbs just to make the experience you need to create 1 good one.
So can u just ground both alternators with a jumper cable and a ground rod or something metal (like a welder )???
Not seeing the info for the alternators, crank pulley and alternator pulleys. For some reason several of the urls given point me back to the listing for the idlers. Thanks.
I see now the alternators came with V pulleys so just need 2 other urls.
So 2 alternators .. can I also use a battery or batteries and an inverter to recharge ?
i would mount one of the generator isolated on a FR4 plate - done
Had you isolated one of the alternators from the other which could have easily been done, with some baker-lite and HD nylon, you would not have had a problem, and the advantage, would have been - if one alternator played up which possible could have been the one you altered then it could have been replaced quite simply, and you would have only had to carry one spare for such an advent , some times sitting back and looking at other ways to solve problems is not a bad idea.
Have you thought about Agni DC motor/generator?
I'll make your life easy: Just get the EG4 ChargeVerter:
Deriving technology from the EG4 3kW All-in-One Solar Inverter, the EG4 Chargeverter is a powerful 48v battery charger capable of charging at 100 amps or over 5000 watts.
100A max charging current for quick charging rates - adjustable from 0A-100A.
Capable of charging a 5.12kWh battery in ~1 hour
Recommended charging current: 30A per battery to maintain battery lifespan.
Optimal for use with a generator. Plug directly into a generator to charge batteries without power quality issues (dirty power).
Inverters typically allow input from a generator as a backup power source. However, budget generators can output “dirty power” or an unreliable sine wave to the inverter, affecting the inverter’s ability to provide consistent power.
To solve this, simply plug the EG4 Chargeverter directly into a generator to charge batteries without power quality issues!
Battery Voltage: 48V nominal.
240VAC or 120V input capabilities (120V configuration requires cable adapter, not included)
Built-in breaker for added protection
Input Cable: 1.5M length
Output Cable: 2M length
I saw a video where someone took a normal car alternator and removed the regulator got it up to 80v. You could do something like this for 48v but I don’t know if it would still do 100amps.
I did try this as well, got up to 100v but of course the amperage dropped in relation to it.
How about connecting them to 2 24 volt batteries and let them charge the battery then pull off 48 volts from the batteries.
they make alternators with permanent magnets that will get you up to 48v.....mine was making 53v or you could use one from lanston alternative energy
and they dont cost maybe up to $500
"To catch a predator"
Perfect name for a go-cart channel
Just stack 4x12v alternators in series. Float the mounting on wood mounts. If the battery bank is 4x 12v banks strap them to the voltage stack. Problem solved!
Each one of those alternators will easily do 48V if you isolate the stator wiring.
Just get a DC to DC boost converter
use both alternators in parallel to feed the boost converter
to produce 48V
You can probably get away with an isolated ground setup like the hybrid system on the early M1009 CUCV’s GM made in the 80’s, where 2 12v alternators were used to make a 24v charging system.
I'm just wondering how phases between the two alternators stay synced? How would you sync the phases?
Of course I'm writing before I watch so...
Parallel? With a boost converter?
240 volts and parallel for the 110volts ,so how are the windings in the usa 110volt output if you have 2 windings is it possible to redo them for 50 volt output
Good idea EMP proof
3:21 seconds in my brain almost exploded when I heard "so we're going to wire them in series to get 48volts." ...ugh... No, you're going to spend less money just buying a better generator than you'll spend trying to figure this out on your own. ... don't mess with the alternators at all. Wire them individually to some custom made transformers that accept 12 volts and have a 48 volt output on the secondary coil. Holy cow people this technology is over 100 yrs old. Just build an appropriately wired transformer for each alternator and add some cooling fins to them on heat sinks and if need be make a 5volt output to power some computer fans to keep them cool.
So a work around to your problem take 12 🔋+ 12🔋batteries and wire them to = 48 volts and then run one of the alternators to one 🔋to keep it charged and the other alternator to other🔋 to keep it charged and then pull 48 volts off the 🔋 🔋
I'm at 13:49 and think I see a fatal flaw in the design. Let's watch the rest and see how this plays out...
Update: yep, that's what I thought. I'm not sure how to separate them, it sounds ridiculous but maybe carbon fiber mounting brackets?? Wood?? Some way to get those grounds(the alternator frames) not to be connected with a conductor, and I think you'll have it.
I think you could have just isolated one of the alternators case so it could be biased to +24v then you could have wired them in series and they would have worked.
Yes this would have been the simplest solution. Isolate one of the alternators from ground so the ground can float and then it can be wired in series.
Isolate the Alts. Hockey pucks. Plus they act a vib dampeners. Cheers! PS - only one needs elec separation.
Hey old question about the split system you installed, you were using resistor to make it run at lower temp, I have a Mr cool system and on the remote it has a Fp button, if you push and hold it it goes in freeze protection mode it will set temp to 46* just fyi shit
Saddest part Is each electronic device and most appliances covert the ac back to less than 48 DC lol like a treadmill motor is 120 dc a 100 watt light bulb operates on 12 v
It would have been cheaper (about $1000 total) and more straightforward with a 3.7KW gas remote start generator, 120v AC output rectified into DC, and using a charge controller to charge the batteries. For all of this, you get a generator that can be used as it is intended at any time and comes with the load regulator/governor.
I'm doing that to I have 4kw generator with 12 v charger charging batteries.
As my sister would say: the thingy connected to the what’s not”.
wouldnt it have been easier to have them in parallel and just use a dc-dc boost converter to do this. it would have been less efficient but might work
Eu que sou da área, isso é colirio para os meus olhos! 😃