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Alternator Upgrades

Discussion in 'Fuel System & Electrics' started by gazman, May 24, 2010.

  1. gazman

    gazman Well-Known Member

    Messages:
    1,821
    Location:
    Perth WA
    So carrying on from another thread - http://forums.kombiclub.com/showthread.php?t=28502 I need to research alternator upgrades and thought I'd ask anyone that has done it for info. Beefed up a stock alternator or retrofitted one from another vehicle? whats available to fit a 1600 or a type IV motor? Whats the highest amp rated alternator available?
    I know that a small number of buses came with an uprated 75A alternator but they are too hard to find for what I need.
    The range I'm after is around 70-100A and I'm keen to hear if anyone has achieved this before.
     
  2. gazman

    gazman Well-Known Member

    Messages:
    1,821
    Location:
    Perth WA
    A quick ebay search found the following from the good ole USA-

    http://cgi.ebay.com/ebaymotors/New-Alternator-VW-Beetle-90Amp-1975-1976-1977-1978-1979- - a 90A type 1 alternator, says to suit beetle, 1600 kombi should be the same right?

    http://cgi.ebay.com/ebaymotors/VW-Mini-Bus-Porsche-914-Alternator-75-Amp-High-Amp-
    http://cgi.ebay.com/ebaymotors/VW-Mini-Bus-Porsche-914-120AMP-Bosch-Alternator-70-76- A 75A and a 120A Porsche 914/type IV alternator.

    I'd still prefer a local (and possibly cheaper) option, but this shows its doable....
     
  3. leithbro

    leithbro Member

    Messages:
    575
    Location:
    Cairns
    cvd does a conversion. you may have a generator not alternator at the moment, which runs through a voltage regulator (rhs on firewall of engine bay - metal box). In this case you will need new fuel pump (as alternators are larger), and new alternator stand. pretty easy job though. don't bother with new tinware around the fan, the old stuff is much better and fits. have a look at http://www.classicveedub.com.au/
     
  4. gazman

    gazman Well-Known Member

    Messages:
    1,821
    Location:
    Perth WA
    Thanks Mark,
    They've got all the bits for a generator-alternator conversion on a type 1 motor, but only do a 55A alternator. I'm probably gonna need one with more ooomph...

    Just noticed Roy sells 75A type 1 alternators. Anyone beefed up a type IV one?
     
    Last edited: May 24, 2010
  5. Nigel

    Nigel Member

    Messages:
    626
    Location:
    Canvey Island, Essex, UK
    I believe the following topic thread, on The Samba forum (which I can no longer access, via the public library computer network, owing to a block on "unsuitable material"), illustrates the flexible-rubber, cooling-air-duct connection, between the VW Type 4 style engine's cooling-fan housing and the 70A alternator.

    Bay Window Bus > Pic of cooling hose for 70A alternator

    http://www.thesamba.com/vw/forum/viewtopic.php?t=305384

    [​IMG]

    70A alternator boot attached to fan shroud
     
    Last edited: Jun 27, 2010
  6. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,818
    Location:
    Penna, Hobart
    Throw a crazy idea out there. What is stopping the mounting of a larger/or indeed additional alternator on a type 4 mounted where the airpump on american models goes. Would involve some mods and additional pulley on the crank. Just an idea, but you could go to a more modern alternator with a larger capacity. Probably not practical but worth considering.

    Adrian
     
  7. Kombi Dad

    Kombi Dad Well-Known Member

    Messages:
    2,426
    Location:
    Bungendore, NSW
    I didn't increase the capacity on my '82 camper but went to an external voltage regulator that can be adjusted. This allowed me to set the proper voltage at the battery to ensure the second battery was charged as I drove. The battery in the '82 is under the driver's seat and the standard alternator would not trip the Redarc isolator to charge the second battery. All works very well now and has since I did the upgrade in 2005.

    Ian
     
  8. gazman

    gazman Well-Known Member

    Messages:
    1,821
    Location:
    Perth WA
    I don't want to have extra alternators cluttering up the engine bay, but I do like the idea of retrofitting an alternator from a different vehicle. Something common and powerful, eg. a Commodore 85A alternator or similar, these also have a built in regulator and later models have internal fans too which would make them a good choice to use. It's not a straight forward swap though and would likely require some engineering ingenuity to get it to work.

    I remember reading somewhere that the 70A parts where no longer available from Bosch so I'd have to check with a good sparky to see if this was a viable option.
     
  9. trevendy

    trevendy Member

    Messages:
    86
    Location:
    Tamworth N.S.W
    On my 1600 (1973) i fitted a Commodore 85A alternator, welded a bracket to the top of the old genny and tigged a idler pully (same size) to the genny pully and used a small ribbed belt to drive it, total cost under $100 and you can pick them up any where, every one thinks it`s a supercharger, would post a pic but the van is away at the moment .....
     
  10. Alpal

    Alpal Moderator Staff Member

    Messages:
    8,497
    Location:
    Melbourne Bend of Islands
    Remember reading somewhere about a 2 generator or alternator that was installed by VW. Maybe for a service vehicle of some kind.
     
  11. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,818
    Location:
    Penna, Hobart
    Yes, I suppose removing the old alt would be more practical, and less complex.
     
  12. Julian Taylor

    Julian Taylor New Member

    Messages:
    25
    Location:
    Maleny
    Hey Gazman I see that this post is 2010 and just stops, what was your conclusion ? My 76 2ltre kombi I believe has the 50 amp alternator and would like to upgrade. I've been looking at a commodore alternator that looks like it would physically fit (14o amp ) however I've wanted to know if you did something similar and found issues along the way ? I don't want to melt things ! The standard alternator is going to have issues charging the standard battery and a secondary battery for camping. So on the face of it this could be a good idea. Cheers
    Julian
     
  13. syncro

    syncro Well-Known Member

    Messages:
    9,324
    Location:
    Southern Highlands
    50A is plenty to charge 2 batteries. It's what ever else that you are powering that is the problem.
     
  14. Julian Taylor

    Julian Taylor New Member

    Messages:
    25
    Location:
    Maleny
    Thanks Syncro,
    Yes, you are right of course. Being a camper it has a 12/240volt fridge, internal lights and driving lights. I'm planing a secondary battery on the opposite side of the engine bay and I think I'll have to drive for many hours to recharge both batteries hence the inquiry.
    Cheers
    Julian
     
  15. gazman

    gazman Well-Known Member

    Messages:
    1,821
    Location:
    Perth WA
    [​IMG]

    Hi Julian, we did end up fitting a Commodore alternator, but its attached to a 3.8lt V6 so I cant really say how it fits on a kombi engine! Assuming you have a type IV engine it should physically fit in place, it would just be a case of modifying or remaking some brackets to suit - depends how handy you are with fabrication....
     
  16. saabman

    saabman Well-Known Member

    Messages:
    4,797
    Location:
    Goulburn
    Your unlikely to charge your battery with more than a few Amps irrespective of the capacity of the alternator.

    As syncro to mentioned it's the accessories that you need the bigger alternator for.

    But unless you really go to town on excess lighting or an electric heater the stock alternator is more than adequate.

    The best thing to do is buy a clamp on ammeter and have a look at how much you do actually require.
     
  17. Julian Taylor

    Julian Taylor New Member

    Messages:
    25
    Location:
    Maleny
    I think I must be missing something here. Surely the depleted battery is going to recharged faster by a larger alternator and as the secondary battery is charged from the start battery there could be quite a deficit to make up. If there was a flat 100amp hour battery to charge the very best you could possibly achieve is to recharge the battery after two hours with the standard 50 amp alternator. Once charged the current decreases unless as pointed out the accessories place a higher demand. Is this thinking incorrect ?
     
  18. saabman

    saabman Well-Known Member

    Messages:
    4,797
    Location:
    Goulburn
    YEs and no.

    this is the simplified version -

    The problem comes from the voltage regulator sets the voltage to around 14V and the charge current is limited by the diffreence between the open circuit voltage of the battery and the supply voltage divided by the equivilent series resistance of the battery.

    So if the battery is dead flat (which your battery should NEVER be let get that flat) thats about 10.5V

    14V from the alternator gives 3.5V difference

    say you have an ESR of 1Ohm

    3.5/1 =3.5A

    as the battery charges the voltage rises so the difference between the alternator volatge and the battery voltage decreases even more and the current decreases even futher.

    Car electrical systems arnt realy designed to charge a flat battery they only give a float charge just to top it up after starting.

    It is a bitmore complicated than that and you wouldget a higher chargeing currentthan thebrief example but evenif it was 10 times higher it wouldnt maintain the high current for very long.
     
  19. syncro

    syncro Well-Known Member

    Messages:
    9,324
    Location:
    Southern Highlands
    Basically if the voltage is the same, then the charge rate will be the same. Smaller alternators, depending on the construction, may actually charge better at lower revs. After a few minutes the charge is never more than 5-10A. It's Ohm's law!
     
  20. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    as other s have said you wont get a great amount of charge difference through the alternator, no matter what you fit, if youre going to a second battery setup then definitely fit a charge controller such as a redarc or similar brand, i personally recommend the redarc SBI12 they are not overly expensive $120- 150 from evilbay as they are straight forward and easy to setup, it will stop you ever flattening your main battery if you wire your fridge and other things to the secondary battery. I also recommend that you spend about $250-300 for a 100-120 amp deep cycle battery as your secondary rather than a standard one as it will cope with the odd total flattening better. Then because you have a pop top there is plenty of space to easily mount a decent solar panel. your looking at about $200 or so for a 100watt one of, ire this to supply power driect to the secondary battery, the redarc controller allows current to flow either way, so will allow power to go to the main battery if needed as well. one tip though, if you look at flexible panels take into consideration that even though it has the advantage that it can be sikaflexed or other flexible glued directly to the roof, a panel has a radiating temp of around 70 degrees, this will transfer heat into whatever it is mounted onto, and as the heat increases the panel efficiency will drop., so flexible panels have been reported to operate far less than what they are rated at, and also make it a fair bit hotter inside the van, the fixed bracket and casing of a solid panel allow an air gap between the roof and the panel and alleviate this a fair bit.
    it may sound like its working out dearer $120 controller+$250 battery+$200 PV panel than a new alternator but you reallyneed the battery and controller anyhow and the PVoption means you are not changing anything that already works and are in fact dramatically increasing your input, as you still maintain the original 5-10A thst the alternator already supplies.
     

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