Direct Current Generators

nigtomdaw
nigtomdaw Solar Expert Posts: 705 ✭✭
in Advanced Solar Electric Technical Forum #1
Hi, still going on the Generator woes, Im now looking at a DC Generator solution in my quest for reliable economical backup battery charging. Ive visted a couple of the sites listed for the homemade Lawnmower Car Alternator setups and seems doable but most list smallish 3hp engines and 50-70 amp 12 volt alternators. Im looking at a 24 volt 150 200 amp setup using say a 10 hp diesle engine. Has anyone had success with any of the home made gennys using a vehicle alternator.

Another option is to use a PMA unit made for wind turbines commercial available based on Hugh Piggots design. It seems sensible to go direct DC to DC and a quick look at the maths seems to indicate for about 10-12hp ic engine I can double my charge rate over the SW thus reducing charging times and fuelcosts by 50%.

I havent come across any decent sized commercial units yet, still looking , would like to hear from anyone with DC generator practical expierience
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  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    #2
    Re: Direct Current Generators

    Hi, I'm quite happy with my "DC gen" which is a standard off-the-shelf 5KW rated AC generator ($US 500) and 3KW AC-DC power supply ($US100, 90% eff. 0.99 PFC, 180-264VAC, 47-63Hz, 44-60VDC). Here is the OB forum thread that I describe it and how to power this baby up - http://www.outbackpower.com/forum/viewtopic.php?p=12059
    GP
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: Direct Current Generators

    One other suggestion... If you choose to build your own (perhaps using a marine alternator/charge controller solution)--use a V-belt (or other belted) type of connection from the generator to the alternator. Do not direct connect using a solid or flex coupling.

    I have seen a small diesel installation (conversion from a gasoline motor to diesel using an old VW Rabbit/Golf motor) connected to an engineering school test bed (basically a large alternator).

    The "solid" connection between the motor and the alternator was constantly being torn apart by the high impulse loads of the diesel motor (high compression/high torque) vs the flywheel momentum of the alternator.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    Re: Direct Current Generators

    Check out the messages here
    http://listerengine.com/smf/index.php?board=13.0

    this is a diesel forum, where much is homemade, or rebuilt.

    14 inch Axial Flux Listeroid
    60V feeding a MX60, fully loaded (is that 60A for the MX60 ?)

    photo story
    This is page 2 - a good beginning.
    http://www.fieldlines.com/story/2007/12/30/21440/810

    The generator consists of 2 discs with magnets, that spin on either side
    of a 3rd, stationary disk, full of coils of wire.
    Mounted on a hub, on the Listeroid Engine's main shaft @ 600 RPM

    This produces AC, which gets rectified to DC, to charge batteries.
    battery bank shown in page 1
    http://www.fieldlines.com/story/2007/12/30/15943/946

    page 3 final touches and comments
    http://www.fieldlines.com/story/2008/1/2/231538/0408
    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 ,

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  • nigtomdaw
    nigtomdaw Solar Expert Posts: 705 ✭✭
    #5
    Re: Direct Current Generators

    Mike thanks for that Im aware of the Listeroids and Hugh Piggots axial flux generator, very interesting a natural marriage but I havent the time or engineering skills to go down this route.

    Bill thanks for the tip I would be going this way as it seems the simplest.

    GP have you got any links to these power supplies remembering Im 230 v 50 hz.
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  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    #6
    Re: Direct Current Generators

    Here is where you can get it http://www.weirdstuff.com/cgi-bin/item/22081#
    And here is the spec http://www.cherokeepwr.com/content/datasheet/CAR3010T_3030T.pdf (single phase 54V, positive ground. The unit sold at wierdstuff seems customed and has different connectors at back. I think the guts are the same as this spec of the standard unit). Look at the OB thread mentioned above for a picture of the actual connections.
    GP
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  • nigtomdaw
    nigtomdaw Solar Expert Posts: 705 ✭✭
    #7
    Re: Direct Current Generators

    Thanks GP, Ive sent them an email asking about the supply of a 24 volt model. They do a 48 volt +ve earth and for my needs a 24 v -ve earth model. Either a 3000 watt unit at 27v 111 amps or a 27v unit at 148 amps. The latter would seen my charging times halfed. Also PFC. Looks good, Wierd Stuff only seem to stock the 48 volt model, can I ask cos Im a little thick why you had to modify your unit. Im very interested but I bet they wount be as cheap as Wierd.com at $99 bucks. The good news is they have a european office. Looking forwrd to your reply. PS they say the output is variable 27-29 volt via pc plug, is this also easy to achieve!

    Thanks again Nigel
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  • sawmill
    sawmill Solar Expert Posts: 93 ✭✭✭
    #8
    Re: Direct Current Generators

    I have a 7hp diesel directly coupled(lovejoy coupling) to a 24v(70amp) automotive type of alternator. With the built in regulator this has been less than satisfactory.

    When batteries are low(no solar) the alt will exceed its amp rating with excess heat on the unit. I have partially solved the heat problem by adding aluminium fins around the outside of the stator for improved heat dissapation.

    When charging I reduce the loads on the inverter to manage the heat. I intend to install a Balmar regulator to hopefully improve performance. At he present time 28v is the max I have seen from this unit with no loads while charging.

    I do not try to fully charge my bank with this unit, it is only used as a fill in for cloudy days.

    There are some good heavy duty 24v alternators available that would be much more satisfactory ie military surplus.

    A Love-Joy coupling that is installed correctly will give hundreds of hours of trouble free service with no side load on your alternator and motor bearings with no belts and pulleys for fingers.
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  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    #9
    Re: Direct Current Generators
    nigtomdaw wrote: »
    Thanks GP, Ive sent them an email asking about the supply of a 24 volt model. They do a 48 volt +ve earth and for my needs a 24 v -ve earth model. Either a 3000 watt unit at 27v 111 amps or a 27v unit at 148 amps. The latter would seen my charging times halfed. Also PFC. Looks good, Wierd Stuff only seem to stock the 48 volt model, can I ask cos Im a little thick why you had to modify your unit. Im very interested but I bet they wount be as cheap as Wierd.com at $99 bucks. The good news is they have a european office. Looking forwrd to your reply. PS they say the output is variable 27-29 volt via pc plug, is this also easy to achieve!

    Thanks again Nigel
    Nigel, I doubt that a standard unit from any retailer would be that cheap. Those are for telecom hot plug PS chassis. I suspect it would be a few Ks. The model at wierdstuff is probably custom and discontinued from some vendor that went belly up.
    I didn't really modify my unit. I didn't find a proper mating connector at the time and "jumper" to have the unit powered on. I had to probe for the equivalent pins on the DB-25 control port of the standard unit. Just like PC power supplies, it won't turn on when power is applied, it needs to be "powered on". You can google for PLA/PLC power connectors, that's what that power connector is. After playing with the internal pot to see the output VDC range, I left it at 54V and feed it into the MX60 to use the staged charging of the MX for by 48V bank, mainly for bulk charging. You can do the same with your 24V battery via the MX (or other CCs). Maybe 2 MXes would give you 120A. On the positive ground, that's for the control logic reference (the DB-25 control port).
    If you ground the negative side, the control logic has to be at VDC out for logic low and VDC + logic high level for logic high. That's all it is about.
    Good luck.
    GP
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #10
    Re: Direct Current Generators
    sawmill wrote: »
    When charging I reduce the loads on the inverter to manage the heat. I intend to install a Balmar regulator to hopefully improve performance. At he present time 28v is the max I have seen from this unit with no loads while charging.

    Any regulator will not help the overheating situation. It's the cooling capacity of the integral fan on the alternator, if you can increase the RPM's and get the fan to run at something closer to it's design speed (10,000 RPM), that will pull more air. Or try a blower and some ductwork, and force air thru the backside of the alt. (Alt's have reverse airflow, the fan at the pulley end, sucks air out of the case, and air enters the rear.)


    > 3KW 48V I purchased here ($100) - http://www.weirdstuff.com/cgi-bin/item/22081#
    > connections: http://www.greener-power.com/images/3KW_PS.jpg
    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 ,

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  • arcandspark
    arcandspark Solar Expert Posts: 63 ✭✭✭✭
    #11
    Re: Direct Current Generators

    For my money the best DC generators on the market are from Polar Power. They make units for the US military. Their alternator design is one of the best designs out there. Check out their web site. POLAR POWER (arcandspark)
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  • nigtomdaw
    nigtomdaw Solar Expert Posts: 705 ✭✭
    #12
    Re: Direct Current Generators

    Hi Ark n Spark , I also came across this website by Yahooing DC Generators what put me off big style was not the excellent gear they were selling but the PDF document on prices, yes pricey but showed a valid price date of Valid Till Dec 2005.......:blush:

    Any fluid company would inspire me with a more fresher price list.... More so than a two year old dusty blow the cobwebs off me were doing great 2005 jobbee!

    Even If I ran a company which managed to keep costs the same for two years Id update my pricelist and shout about it.:D


    Maybe Im just synical..........Please prove me wrong !

    The website was last updated in 03-2005 me thinks no longer trading :cry:

    But I could be wrong Im not unfamiliar with that :p
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  • arcandspark
    arcandspark Solar Expert Posts: 63 ✭✭✭✭
    #13
    Re: Direct Current Generators

    Polar Power is still in buisness, they are so buisy with military systems they have not been able to update their web site. For my money they are number one, on the cutting edge. They have a few new generator systems and their co-generation system is the best I have seen.

    Email from Polar Power received 2-21-08
    David,
    We are still in business.
    We are getting so many email and phone calls for electric hybrid boats,
    automobiles, military, etc, we have not had time to update the site.
    Regards,
    Arthur

    I highly recommend their equipment over anyone else I have seen and tested.
    Dave R. (arcandspark)
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  • nigtomdaw
    nigtomdaw Solar Expert Posts: 705 ✭✭
    #14
    Re: Direct Current Generators

    David thanks for that , Ive since bought a 160 amp 28v ex UK military unit,, have a look at my thread . An interesting bit of kit
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