Small engine driven battery charging alternator.

oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

Has anyone tried using a small engine driven automotive alternator for occasional battery charging?

Taking a single phase generator that makes 120 or 240 volt single phase power then stepping it down and rectifying it to a much lower voltage and trying to smooth out the AC pluses seems pretty inefficient. 

If you were to generate the same amount of electrical power with 3 phase the engine could do it with 11% less engine torque. Then creating it only at the voltage you needed and charging batteries instead of trying to step it up and down and smooth it out sounds so much more efficient.

To buy a good generator and battery charge and generator costs a lot of money. Everyone raves about the inverter generators being so efficient then cries when they see the price tag, because they are variable speed and the sourced power is 3 phase. A alternator based DC generator charger does the same thing.

For a 12V system simply just engine driving a common alternator with a small engine and belt drive would give you what you need.

To make 24V you would need to buy a 24V alternator or take a super common alternator available with 12 and 24 volt versions and swap in the 24V regulator. Such as could be done with an SI-10 or SI-12.

48 volts would be a little more difficult. I think you would have to take apart the alternator, remove the rectifier because its only intended for 24v max, wire to an external one, provide 12vdc to power the voltage regulator and put a voltage divider on the V-sense to trick the alternator into producing the roughly 55VDC you would want to charge a 48 volt system.

It sounds a lot cheaper than buying a generator and battery charger for emergency charging.

What do you think?

Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

Comments

  • BrockBrock Solar Expert Posts: 633 ✭✭✭✭
    I used to have a 12v genset.  It was made from an old lawnmower engine and a marine 140a alternator.  It worked fine, but was loud as heck, but in a pinch it worked fine.  I ended up purchasing a Honda 2000i, amazingly quiet and ultimately more efficient becasue I can max out charging via external charger instead of relying on what the alternator could do which would drop off rather quickly do to wiring loss, even with tweaking the alternator settings.  The other advantage of the Honda is the 120vac out for portable loads as well as running a 120vac line to the good 3 stage charger at the batteries and the Honda spools up or down as the load dictates.  But yes, it is more expensive.
    3kw solar PV, 8 L16's, xw 5548, Honda eu2000i, iota DLS-54-13, Leaf EV, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    I am just going to run something like a Honda GX200 to power a 140 amp alternator.

    The GX200 is a little more than I need but the idea would be to not run it wide open.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • mike95490mike95490 Solar Expert Posts: 8,369 ✭✭✭✭✭
    Most automotive alternators cannot sustain full power for more than a couple minutes, they heat up and output drops off.   Look at some of the Balmar choices. Find the RPM that has the best cooling, and that's about as good as you can manage.
    http://www.balmar.net/?page_id=15484

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    That is why I was going to run it at partial speed.

    Good thing about the automotive alternator is everything inside them is rated for 200'C.

    Good think about using one in this application is its normal operating environment is over 100'C, this application will have the alternator in a much cooler environment. And I was already planning on running an external bridge rectifier and voltage regulator to allow less heat to build up in side the case and allow for better cooling.

    I don't think over heating will be a problem because I wont be running it at max rated amps and when automotive alternators are converted over to welding alternators they have a 100% duty cycle at full power.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • Dave AngeliniDave Angelini Solar Expert Posts: 4,659 ✭✭✭✭✭
    Automotive alternators do not have the load that a big bank of batteries  and house loads will have. You will fry it so have spares!
    Your logic is leaving out the time factor. The battery you have now may be fine but as your system grows this will be a problem.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    My small systems have already grown to their absolute size.
    Not planning on using the automotive alternator to act as a replacement for batteries.
    Plus I have my 7kw generator. If i need sustained power i just fire that thing up. I am trying to avoid running a 400cc engine to power a 340 watt battery charger to charge my battery, but instead run a 1,000 to 1,500 watt battery charger with a 200cc engine to charge the battery and power small demands while the battery is bulk charging.
    I am not looking for a solution to power everything, only looking for more charging options.
    I have already standardized on SI-10 and SI-12 alternators. I will always have at least 1 or 2 spares on hand.

    So what am I missing again?
    Or am I just irritating people by not going into lock step with the status quo?

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • mrfixitmrfixit Registered Users Posts: 16 ✭✭
    I use a leese-Neeville large frame truck alternator mated to a 2 cyl. yanmar diesel with excellent results.
    No issues with sync up to the inverter, or dropping out under load like a AC generator even with gen support.
    It just works all the time every time.
    I use an external regulator but still am using the internal rectifier diodes.
    Heat hasn't been an issue as of yet,as it is spinning faster than typical use to get the higher voltage for a 48 volt system but doing so the fan moves more air flow thru.


  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    What all did you do to get it up to 48 volts?

    Just change the voltage reg and spin it at max speed?

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • mrfixitmrfixit Registered Users Posts: 16 ✭✭
    12 volt regulator with the sense line connected at the 12v point on the 48 volt bank.
    It is running at approx. 6500rpm with the diesel at 2200rpm.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    What kind of automotive alternator did you use?

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • mrfixitmrfixit Registered Users Posts: 16 ✭✭
    Most of the large frame Leese-Neville truck alternators have external regulators that are easy to remove. The one I'm using is 160 amps @ 12v nominal.
    The field terminals are easy to get to for wiring in an external regulator that's adjustable like a Balmar.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Looking into the more it appears very viable. I was thinking about using the Government Motors AD244 series. They are 253 amp for the big standard size and are delta wound. I don't think that a 6hp motor could hold much more than a 150 amp load at 14 volts. The over size would be for better heat disbursement.
    Instead of running a 140 amp alt at
    140 amps and expecting it to last.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • E.WelderE.Welder Registered Users Posts: 4

    Please go into more detail. I have a 48 v bank of 8 6v gc batteries to charge.  Have lots of small engines to power a alternator.  I can not figure out the wiring. How is the voltage controlled with rpm?  E.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    The voltage is controlled by the voltage regulator.
    And the built in rectifier may not be able to handle over 50 volts.
    To get the alternator to produce 50 volts or more just connect the V-sense to the last string of 12 volt batteries.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • t00lst00ls Solar Expert Posts: 212 ✭✭✭
    have a look at windblue.....you cannot use a regular alternator to charge like you want to......however a permanent magnent generator will work

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Yes you can use a regular alternator to charge 48 volt bank.
    Did you not read mrfixit posts on using a 12volt truck alternator to charge his 48 volt bank?

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • t00lst00ls Solar Expert Posts: 212 ✭✭✭
    the problem with a regular alternator is that it has brushes that wear out over extended use.....also, you have to have power to "excite" the diode before anything will happen, which is really inefficient

    yes I know you can charge a 48V bank with that alternator......but it wont last very long

    I have a windblue generator....you can hook them up to a mppt controller and set the tracking voltage and it works very well....did mine like that till my gas engine blew

    working on a water storage idea I have

  • E.WelderE.Welder Registered Users Posts: 4
    I am thanking 8 6v batteries in a string p+ to n- don't know their is 60v on the last +.  The field voltage is controlled by the regulator where the brushes transfer  their normal amps to the rotor. I have a altenator on my truck with close to 300,000. miles and 34 years on it and never ben touched. Dang should not of said that.  Brush life should be no problem. Voltage regulator tapped at 12v point from ground.  I have convinced my self it will work . Will start collecting parts to build it.  What do you think ?  E.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    How much does the wind PMA cost?
    Because I am seeing new 250 amp AD244 alternators for around $100 shipped.
    Brushes are easily to change and under $20.
    The serries of 8 batteries that make 6 volts will make about 50 volts normal. It will take 60 volts to preform equalization.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • soloronesolorone Solar Expert Posts: 250 ✭✭✭
    edited June 2016 #21

    Oh, are you talking about something like this 1983  version I lived with for a short while ?  12 V. note the 600 MCM on the ground, it had a potential of  180 A, but we kept it at about 60 to 70.  Used Alt. were cheap then, most I paid was 15 $ most were 5$. They might run one  day or run a year, kept plenty of spares and FORD was the only none regulated Alt.  at that time that I knew off.  The field was controlled by a dimmer switch from a 70s  Cadillac  since that or one from  a big Lincoln could handle the heat generated from the rheostat..

    Thing about a gas motor, they have a mind of their own, and this one whooped a grown man and a 16 YO son into the ground one night, of course  when It was really need too. Next week I was buying panels.  But this was the cheapest I ever ran the house, about  13$  a month.

    For a backup it might be cool, I have thought about it building another  small one.   

    http://forum.solar-electric.com/discussion/4656/true-alternator-energy#latest

  • E.WelderE.Welder Registered Users Posts: 4
    I like your approach. I bet you had the belts before you built the mounts. noticed the open exhaust so engine is froze up now?  Got to looking for a alt I got out of a dumpster to build a dc charger out of turns out to be a 1999 2000 jeep deso  210-0493 100 amp. The rectifier has 4+and4-diodes mounted on the back of the alt outside, has2 fans and no regulator.  all easy to get to.  My brother just gave me a pressure washer with a good motor bad pump. did Chrysler have a simple reg on their first alt cars?  More later E.
  • mrfixitmrfixit Registered Users Posts: 16 ✭✭
    Here's my setup, Yanmar 2tnv and leese-neeville 7706 alternator


  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    A diesel and a leese, that's hard core. I like it.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Where did you get that belt drive on your yanmar?
    I am thinking about going diesel for my big alternator rig build.

    I am going to start building a test rig, just an AD244 alternator on a Honda 6.5hp motor.
    Would like to build a double alternator rig using a gas or diesel engine up to 30hp.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • mrfixitmrfixit Registered Users Posts: 16 ✭✭
    The pulley came from Surplus Center a few years back.
    It was a front pulley off of some type of engine(not sure what) and it took quite a bit of modifying it to bolt it to the yanmar flywheel.
    The alternator has over 200 hours on it now.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    oh alright, I was thinking you found some bolt on pulley.
    I too have modified pulleys for applications for which they were never intended. Its pretty time consuming but so far has always worked for me, that is why I figured I would ask.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • bill von novakbill von novak Solar Expert Posts: 850 ✭✭✭✭
    oil pan 4 said:

    Has anyone tried using a small engine driven automotive alternator for occasional battery charging?

    Taking a single phase generator that makes 120 or 240 volt single phase power then stepping it down and rectifying it to a much lower voltage and trying to smooth out the AC pluses seems pretty inefficient. 

    If you were to generate the same amount of electrical power with 3 phase the engine could do it with 11% less engine torque. Then creating it only at the voltage you needed and charging batteries instead of trying to step it up and down and smooth it out sounds so much more efficient.

    You have to deal with the "AC pulses" anyway.  Alternators are AC generators; they use diodes to rectify to pulsating DC.  (They are typically 3 phase to reduce the pulsation, but it's still there.)

    But alternators are a pretty good solution for off-grid systems.  For on-grid systems, of course, there are big advantages to AC generation, the primary one being you can use it directly.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Rectified 3 phase DC pluses are a lot easier to deal with than rectified DC single phase.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

Sign In or Register to comment.