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Forum Index : Electronics : Converting regular alternator to 48 volts
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renewableMark Guru  Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Maybe look into treadmill motors, they are permanent magnet DC. You'll need to get the gearing right and probably run two or more to get enough power. Having an mppt that could handle a wide voltage range could possibly work, not sure how that would load up the motors though. I very nearly bought one of these for backup power, every time I think it's needed the system handles the conditions fine. You can buy the stators and rotors for these individually, but then a custom mount and shaft would need to be made. There is a slight possibility if the inside isn't all potted that you could rewire the coils from this to suit your voltage needs. Or maybe able to rewire one of these I think by the time you muck around and have to buy a controller to handle the power it's probably wiser to get a ready made unit that will just bolt on and work. Here is a bolt on option. I know it's pricey but all this off grid stuff is. Edited 2019-08-08 07:48 by renewableMark Cheers Caveman Mark Off grid eastern Melb |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
That is an awesome little generator mark and at that price you can probably buy one cheaper than you can make it I have a brand new 3 horsepower permanent magnet treadmill motor I also have the speed controller for it it's pretty cool Edited 2019-08-08 07:40 by BenandAmber be warned i am good parrot but Dumber than a box of rocks |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
I wonder if a Industrial induction motor rated for continuous use will continue to Output power above the 10% of the name plate RPM If so that may be a good way to go just Rectify that to DC and put it through an mppt charge controller as long as the voltage isn't above what the mppt charge controller can handle Warpspeed will probably chime in here sooner or later I still think a regular 48 volt internally regulated alternator would be the very easiest but the price is just outrageous If I did go that route I can probably do away with the gasoline 48 volt battery charger I wouldn't need it I could just start up the bus if the batteries didn't get all the way charged from the solar panels I'm hoping those days will be very seldom be warned i am good parrot but Dumber than a box of rocks |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
I still don't get why you are wanting to go 48V when the rest of the bus is 12 V and you have a 5Kw inverter? There are leece Neville alts that will do around 5KW @ 12v so you could use them to feed the inverter to run the AC. An Induction motor generator will work and I have done this with a GTI. On a stationary engine the GTI will cause it to hunt through the MPPT but the reactive power you would have with an engine that size driving a bus would laugh that load off completely. The problem you are going to have is the varying RPM but it may be OK. The faster you spin the engine the higher the voltage on the IMAG will be. Given a 6V92 will spend the majority of it's time in an 800RPM rev range, You could set it up for highway speed revs and it should be OK for the 400RPM either side. You could also maybe look at an auto switching system for the caps where at higher revs the caps are switched out and at lower revs more caps are switched in. Really would depend on the Motor you get and the rev range of the bus engine. You would want to be able to monitor the output and have a switch to re flash the windings from the drivers seat if the revs get too low and the thing looses excitation which is easy to do. You could also set up a standard Gen head the same way. Rectifying the AC output will give you about 140-150V DC from a 110V head so should be in the ball park for a MPPT controller input. Not sure if a head with AVR would be happy or not with the varying speed but from memory I don't think they do anything about frequency. There may be parameters where they need a fairly stable speed. In any case if you set up for engine RPM at normal cruise speed you'll be ok most of the time. Engine is probably going to run around 1200 RPM to 1900 Flat out so a decent gen head should handle that. For a gen head I'd recommend getting 4 Pole which will make the cruise RPM of the engine pretty close to the RPM the gen head ideally wants anyway and keep the pulleys similar sizes. I still think Given the cost factor and or stuffing around factors, seems to me to be infinitely cheaper and easier to drive a compressor off the engine especially as you will probably driving for hours at a time and the cooling capacity you could draw direct is going to far out strip what you can do electrically. |
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| Ironmaiden Regular Member  Joined: 09/07/2019 Location: United StatesPosts: 53 |
I was going to suggest an induction generator as well. I've built many of them over the years. The problem is though they don't like other large induction motor loads. AC compressors are the kind of load that would make them have a fit. His best option is to A. Install the Onan for HEP Head End Power. Sorry I'm a railway man so I will be using terminology from the industry. B. Install a 12/24v alternator like a Leece Neville. C. Just put the dang compressor on the diesel engine for the AC system. This is the best approach after all. D. Use a hydraulic pump to drive a hydraulic motor generator setup. The fire Trucks and several semi trailer trucks do this now for power. Give Fabco power a call and see what they can do for you? They make the belt driven AC generator I linked earlier. They also supply the hydraulic generators too. There is no reason why the forward bay couldn't have the Onan and his 6v bats at the back of the bus. Maybe have the gen use the same fuel supply as the bus engine? I think Ben is over thinking things and wanting to re-invent the wheel too much here. I'd treat the bus as a private railroad passenger car. Self contained with electric AC/Heat and a diesel generator slung under the floor to supply the AC power needed. Robert Edited 2019-08-08 09:18 by Ironmaiden |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Dave at the beginning of the thread provided a link to brand new Chinese 48v alternators for as little as $32.00 Here it is again: https://www.alibaba.com/product-detail/Alternator-48V_60640524599.html?spm=a2700.7724857.normalList.34.1bbf593ctrDrSp As far as I can see that solves the whole problem. Cheers, Tony. |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Mate, Says 12v in the details section. 48v is a odd voltage for a alternator of this type. They do make a vehicle alternator for ambulances that can supply 120/240v and run the vehicle electrical system. I almost had one too. Dang it! I knew I could find a use for it eventually. Shoulda got the darn thing. The miltary uses some of the biggest badazz alternators in production. Names like CE Niehoff and Pacific Scientific come to mind. They are expensive so shop around for one on the surplus market. Robert Edited 2019-08-08 09:26 by Ironmaiden |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Product Description Product Name Alternator Voltage 12V 24V 36V 48V Current 30A / 50A / 80A / 90A / 100A / 110A 150A / 200A / 300A Car Model For Chevrolet / Toyato / Nissan / Mitsubishi / Chrysler / Mazda, Daewoo etc. Advantage Low fuel consumption, easy starting, lightweight, long service time Cheers, Tony. |
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| kentfielddude Regular Member Joined: 09/05/2019 Location: United StatesPosts: 89 |
How much power does your AC use and how much battery capacity do you have? If you're not planning to drive your bus for hours at a time the solar would probably do just fine. Most of the time your bus will just be sitting parked somewhere so your battery would be fully charged by the time you want to use them. You could carry a small generator for backup if you wanted. Edited 2019-08-08 11:00 by kentfielddude |
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| johnmc Senior Member  Joined: 21/01/2011 Location: AustraliaPosts: 282 |
Regarding the Chinese alternator supplies when you look closely, you will find it is a 12v 30 or 50 amp alternator. I only found 1 supplier for a 48v alternator. $$$$$$. There is also Australian supplier of 48v alternators for the mining industry $$$$$ cheers john johnmc |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
All these ideals are awesome and I appreciate them I think you are right about me overthinking it I'm going to go to the site that warp speed posted and inquire about a 48 volt alternator this is the easiest simplest way to do it If the 48 volt ones are more expensive I'll just have to save up because it's likely to be a lot cheaper easier and more reliable in the long run I don't need a giant amount of power just something to help out I would be happy with a thousand Watts I have already built a 48 volt inverter for the bus from what I read 48 volt is a lot better than 12 or 24 Also I don't need as many charge controllers if I went where 12 24 I would have to have at least double the charge controllers I would have preferred to do a 96 volt inverter and Battery Bank The only reason I didn't is because if one battery failed I wouldn't have a battery bank because I only have 8 batteries And 96 volt charge controllers are a little bit rare right now I think sooner or later everything will be higher voltage like this 96 volt will be the norm in not too many years I do believe A 5000 BTU air conditioner runs on about five or six hundred watts I will probably be running one 14000 BTU And to 5000 BTUs air conditioners I will be taking the air conditioners off the top of this bus to make more room for solar panels I will likely be using a few mini splits if the price is right If the price is too expensive then I'll be using 3 window air conditioner units mounted under the bus I will rewire them to a regular digital thermostat and duct them up through from the bottom If the condensers are big enough in them then I will be putting a reversing valve in them also I like the idea of having three zones in the bus that way I can conserve energy when necessary I have over 2 inches of foam in the ceiling and 5 inhes rockwool insulation in the walls We are wanting to have some kind of in floor Heating also not sure about the best way to go about that yet I was thinking if I went with some kind of liquid in floor heating I can put a dump load for the solar panels into a heating element Any ideas would be really appreciated on this subject also Sorry warpspeed but sometimes you got to tell me twice before it gets through my thick skull Edited 2019-08-08 11:50 by BenandAmber be warned i am good parrot but Dumber than a box of rocks |
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| kentfielddude Regular Member Joined: 09/05/2019 Location: United StatesPosts: 89 |
I have tried to buy stuff from Alibaba before but never made a deal. Either the price that was advertised was for very large bulk purchases or fake to lure customers. Also the shipping was expensive. |
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| kentfielddude Regular Member Joined: 09/05/2019 Location: United StatesPosts: 89 |
Lets say you're drawing 2500 watts for your 3 air conditioners. If you have 3kwh of solar lets say you get an average of 2400 watts driving down the road during mid day. Even if you have lets say a net draw of 300 watts a 3-4kwh battery would last several hours. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I have had similar problems with Alibaba. But in this case they are advertising for a one off, and if you scroll down the page the product description definitely says 48v alternators are available. The largest they mention is 12v 300A which is probably the most expensive, with the largest frame size. The 48v unit is very likely 75 amps max, using the same frame size as the largest 12v unit. Well worth sending them an e-mail and finding out for sure. Cheers, Tony. |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
I'd say if your not going to put the AC compressor on the diesel, than look into having a hydraulic pump and motor driving a generator. $$$ though in parts. Just forget the damn 48v and use 24v. Truck alternators are plentyful. A Leece Neville would charge your batteries on the fly. If your stuck on 48v, Than use a set of knife switches and connect the batteries for 24v for charging and 48v running. Use the Buses engine for AC while in motion and electric AC while standing still. Here's a 48V alternator. $1500. https://www.auroragenerators.com/products/48-volt-generator Using regular window AC units in that fashion is a hack job at best. They only have styrofoam ducts in them nowadays so ducting them would be lossy at best. Split units might work. I'd say keep the roof units. Ditch the solar panels you have for higher wattage ones so you can use fewer of them.  Selling the old ones for profit would help you get bigger and better panels.Ever think about pulling a trailer with solar panels on it? A power sled! Personally, I think utilizing the diesel engine for both lights and AC is the way to go. When the big engine is shut down a smaller diesel under the floor is the way to go. Both of them could be setup to use heat exchanger units on the exhaust to provide your hot liquid heating system. You need a large tank and pumps and by-pass valves for it all to work. Robert Edited 2019-08-08 11:50 by Ironmaiden |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
Yes me and the wife has been thinking about pulling a trailer behind the bus that is a pretty awesome idea That would be a lot better than having to have a awning made of solar panels slapping going down the road As far as solar panels go I thought I had the best ones already thay are 330 watts per panel The pannels came from a electric company that was installing a large array and a windstorm came before they got them all the way installed and bent a couple bolt holes on the back of them So they've never been hooked up and I got a really good deal on them because it was an insurance job I got a good deal on the batteries I have also or I wouldn't have been able to afford them And as far as my inverter goes if it hadn't been for the good people on here I wouldn't have been able to afford to do this project I've tried to let people know how much I appreciate them but I still don't think they know what kind of impact they've had on me my family and a few friends lives I am very poor and poor people have poor ways I live in a poverty-stricken state actually below poverty we're blessed by God with happiness and able to help other people along the way which is the biggest blessing of all if you could only pick one wealth or happiness which one would it be? a lot of you guys on here have contributed to that even though most of you may not know it I'm kind of like Forrest Gump I just keep having faith and helping everyone I can and what we need ends up coming along for free or price I can afford Thanks everyone be warned i am good parrot but Dumber than a box of rocks |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Sites running only at half power which has been problematic when it comes to replying. Hopefully this will be fixed before too long. I didn't want to sound harsh. But rather I am just a bit annoyed by some of the rather poor ideas I read about A/C. Honestly, Efficiency would be horrible and waste energy. 330w panels. Nah, They have em bigger now. I've seen a stack of 375 watt panels recently. Research shows panels up to 500 watts being available. I understand the poverty issues. I was looking at the cost of setting up a farm light plant style system. My battery bank alone comes up to $3K. I've decided on tried and true Lead Acid because I don't care for all the Lithium Ion crap. They are time bombs waiting to explode. I really like Nickel Iron batteries. Since no one uses them they don't make em here anymore which makes them prohibitively expensive to obtain. The worthless azz turds known as the EPA banned the Lister engines here a couple years ago. I want to have Lister CS 6/1 turning a Leece Neville alternator for backup to my solar panel/ wind turbine setup. The solar would set me back another $3k. Lister CS $2K assuming I can find one in good shape. Wind turbine $??? I like the old Wind Charger units. They had them in 12v models. I'm either thinking 12 or 24v for ease of compatibility. The Old farm light plant systems were usually 32v or 36v which is better for 5000 watt inverters all day long. The real rule of thumb is as follows, 12v 2KW max 24v 4KW max 32v 5-6KW Max 36v 6-8KW Max 48v 8-9KW Max Those are actually pretty close when you run the numbers on amperes flowing from the batteries at LV DC. I think it's sobering reminder of the poor efficiency of these systems. The rail industry uses 72v DC to start the big diesel electric locomotives. 72-96v systems would be far more practical for a modern US households power consumption on solar/wind. Even 110v DC looks more favorable. I just want to have a decent 2500 watt system in the style of the old Delco light plant systems. I guess maybe it will happen one day. Robert Edited 2019-08-08 16:53 by Ironmaiden |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Ben I know it's a fair bit but this one at $629 is probably as cheap as you'll get even if you make something. That is a 90A unit. 90Ax56v =5000+watts That will power anything you want on the road and be a great backup charger when parked. Cheers Caveman Mark Off grid eastern Melb |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
That's a pretty good deal and that's the name brand I've been looking at be warned i am good parrot but Dumber than a box of rocks |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Ben, One of these in an empty bay would work out great. Onan Diesel It's one of the newer Onan inverter diesel generators. Robert |
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