1. 67DARTGTCONV

    67DARTGTCONV Well-Known Member

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  2. grumpuscreature

    grumpuscreature Resident Curmudgeon

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    It's a lot cheaper and just as effective to put 2 batteries in the trunk......
     
  3. 67Dart273

    67Dart273 Well-Known Member

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    ???wtf???
     
  4. grumpuscreature

    grumpuscreature Resident Curmudgeon

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    Don't knock it if you haven't tried it....
     
  5. ram250098

    ram250098 Well-Known Member

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    You can have yours upgraded to a 100 amp, I WOULD THINK ANY AUTO ELECTRIC could do it for you, I have had that done before. But if your going to buy one, buy from a good manufacturer...I bought a Tuff Stuff last year to try them out....a dud right out of the box...
    AL
     
  6. 67DARTGTCONV

    67DARTGTCONV Well-Known Member

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    THanks,

    I figured if I was buying a new one I would go with chrome hence the Tuff ones.

    Does everyone agree the square back outputs better at idle?

    I have searched threads here and it seems to be the alt of choice although no mention if internaly regulated
     
  7. 6pk2goDemon

    6pk2goDemon Mopar Mod Staff Member FABO Gold Member

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  8. Rice Nuker

    Rice Nuker Let the Coal Roll!

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    Switch over to a modern alternator like on a 90 dakota or similar.

    Older Mopar alternators do not generate enough wattage at idle and you cannot engineer that out of the design with a 100 amp mod. It helps a little, but not much. I have a very nice tuffstuff 100 amp mopar alternator and the voltage still drops badly at 600 rpm idle. Voltage is 14.5 at 1500 rpms and it goes back to sucking at idle.

    You didnt mention if you have upgraded your wiring but running a 6 gauge from your alternator + to your starter relay post + and deleting the runs to the amp gauge is a much needed start. Mopar wiring system is sadly anemic from one end to the other.
     
  9. kt340sport

    kt340sport Well-Known Member

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    You can get the square back alternators in 75 Amp stock , there is one on my Dart Sport .
     
  10. 67Dart273

    67Dart273 Well-Known Member

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    A square back will help a lot, but the rest of the system has to be in good shape, too. Have you read the MAD article? Have you looked over your harness, and bulkhead connector?

    How about the headlight harness? Do you run headlight relays, and what are you running for headlights?

    http://www.madelectrical.com/electricaltech/amp-gauges.shtml

    And adding "more battery(s)" unless the one you have is completely inadequate, is no solution. SOMETHING has to charge it/ them back up!!!

    So far as alternators, there are several ways to go. Hell, way back in the mid 70's I used to run a Delco integral unit on my 340 Landcruiser. This was before Al Gore invented the internet.
     
  11. KitCarlson

    KitCarlson Well-Known Member

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    I get it, with two batteries, one can charge the other. :)

    Not .
     
  12. grumpuscreature

    grumpuscreature Resident Curmudgeon

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    No, with 2 batteries you can draw more current without a large voltage drop. You don't need 100 amps to charge a battery. If that were true trickle chargers for battery maintenance would be totally useless. Like your comment.....
     
  13. Big Block Hippie

    Big Block Hippie Member

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    The Denso Alternator off a 1985 toyota works great off idle great simple mod.
     
  14. 67DARTGTCONV

    67DARTGTCONV Well-Known Member

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    Thanks for all of the responses.

    For sure I am following up with the wire harnes mods that everyone mentions here.

    Is an alt from the 90 Dakota bolt on??
     
  15. the67fish

    the67fish Well-Known Member

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    60-65 amp is more than enuff for most any application unless you are running a welder with it at the same time!!
     
  16. 67Dart273

    67Dart273 Well-Known Member

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    Nope. You have to replace every single bit of power that you draw OUT of a battery. There is no reason in the world to need two batteries in any car. If the charging system won't run the car, then you need to fix it as needed.

    And "More batteries" wont' fix lamp dimming, anyhow. The charging system runs nominally 13.5--14.2 when running, and dropping DOWN to battery voltage, IE 12.6, WILL cause a noticeable drop in lamp brilliance.


    The one thing I agree with is the part of your statement, "You don't need 100 amps to charge a battery" But you certainly cannot drive down the road with the equivalent of a trickle charger, either.
     
  17. BillGrissom

    BillGrissom Well-Known Member

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    Totally agree and with 273. I just answered this, so excuse me if I am ranting. The headlights should be bright with the engine off (i.e. no alternator). If not, the path from the battery to the lights is bad. The only vehicle where revving the engine should affect the lights is a 1970's 2-stroke motorcycle that didn't have a battery. Your alternator's purpose is to recharge the battery, so if your battery isn't running down, yours is plenty big. Don't waste $170 on a new super one.

    The components to check are your bulkhead connector, ammeter connections behind dash, and headlight switch. You can quickly find the main voltage drop with a multimeter. If enough current, the part will get hot too. Many people have experienced melted bulkhead connectors and dash circuit boards. Smart to find and fix it before it melts. A bigger alternator will just help you melt it quicker.
     
  18. moparlover

    moparlover Well-Known Member

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  19. RedFish

    RedFish Well-Known Member

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    If the fault is only in the headlights the headlight switch or dimmer switch could be the fault. If the amp gauge drops with lights on and/or twitches along with turn signal operation the charging system is at fault.
    Diagnosing comes before fixing.
     
  20. 66plyValiant

    66plyValiant Well-Known Member

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    lets see, $100+ for a battery, $50+ each for battery cables to the rear where there is space and you have $200.

    now lets compare the proper way,

    $80 for new squareback alternator, $25 for solid state voltage regualtor. 3 hours or less to wire it in.

    so how is that more cost effective for two batteries? two batteries are for more cranking amps when starting like in a diesel truck, once it starts you need to charge those batteries just the same as any vehicle would. and if your having problems charging one battery two is going to be worse
     
  21. moparlover

    moparlover Well-Known Member

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    yep. replacing the headlight switch, bypassing the alt gauge as per the mad electric site, and possibly doing the firewall alt wire/battery wire mods as well will go a long ways and would probably fix your problems without changing alternators. the extra alt amps definitely are needed if you are running electrical fans for your radiator/trans cooler or if it's a truck and you have a snow plow, extra lighting, etc.
     
  22. jbc426

    jbc426 Well-Known Member

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    All you need to do is use a dual field alternator with a small external voltage regulator. Any alternator shop can put one together for you for reasonably cheap. The regulator I had was the size of a book of matches and attached right to my alternator. ( if you look closely, you can see it on the side of the alternator in this picture) I left all the factory regulator stuff right where it was and even left it hooked up. I did add a new cable with fusable link from the alternator to the starter relay.

    If you add a larger cable from the alternator to the starter relay(use some fuseable link on the end), it will help keep excessive amperage out of your bulkhead fitting and amp guage and route it directly to the starter relay and battery.

    This was the only mod I did on my '68 Barracuda when I had the slant six and it worked great. Lights were brighter especially at idle, battery charged way better and ignition worked better. Cost me under $100 for the new alternator, the mini electronic regulator and the cable etc.

    PS: I did not have any additional amperage being drawn inside the car. If you have a big stereo or something, be sure to add it at the starter relay and not inside the car, as it would have to go through the bulkhead connections and that's not good. They are wimpy enough to begin with.
     

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  23. BillGrissom

    BillGrissom Well-Known Member

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    Except those of us with a 1965. The engineers were smart enough to use dedicated lugs for the big wires that year only. A bean counter must have nixed the design later.

    The squareback alternator (isolated field) does output a bit more current, but for most people the older round-back is fine. I have used one in my 65 Newport for 20 years, with TBI, electric fuel pump, and AC. No electric fan though. The only time it failed to keep the battery charged was when one of the diodes inside failed so wasn't outputing spec current. The square-backs are easier to fix. I got real used to replacing the high-side diodes in the one in my 82 Aries since they vaporized every few years. An auto electric shop told me that was a common problem. Might have been due to the transverse engine orientation.

    If anybody really thinks they need more current, PM me. I want to unload a rebuilt 110 A Mopar alternator I got on ebay. It is supposed to bolt up directly. You can see one in the Autozone website. It is much larger and heavier than I imagined from the photo, maybe 50% bigger than stock. I wouldn't even put the beast in my Newport. I think they were used in trucks, maybe with winches and other accessories. I'll take a loss to get it off my shelf.
     
  24. 67Dart273

    67Dart273 Well-Known Member

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    Sorry I disagree completely with the idea of a different regulator. There is nothing wrong with the factory regulator, if replaced with one that properly works. Most replacement regulators for the pre--70 stuff is already solid state.

    (There is ONE possible problem linked to the regulator / field circuit, and that would be low voltage TO the regulator caused by voltage drop in the ignition harness. At low RPM when the alternator cannot keep up, the field current may drop additionally at idle, worsening the problem. This is often the cause of the cyclic "dim/ bright/ dim bright" low voltage oscillation that occurs in some cars. This is OFTEN not a regulator problem, but rather a harness voltage drop problem)

    "Dimming lights at idle" is not repaired by replacing the regulator. It is repaired by using an alternator which PUTS OUT MORE at low RPM.

    What I find amusing is that with all the changes you noted, in your photo you still have the old round--back style, which are noted for low output at low RPM.

    This I agree with, but ONLY after having improved, repaired, or bypassed the bulkhead connector. Otherwise, the charging current has to go in/ out of the bulkhead connector
     
  25. crackedback

    crackedback FABO Gold Member FABO Gold Member

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    The solution that 6pk2goDemon mentioned is the best way to get rid of the horrible voltage drop that the factory 18 gauge headlight wiring provides, not to mention two passes through the bulkhead. It also get the headlight load off the bulkhead and ammeter.

    Get rid of that insufficient wiring and you'll have a much better lighting experience.

    Rice Nuker hit on the other, alt rpm is an issue with factory mopar alternators. I don't recall the max RPM on a mopar alt, I run the densos to a max of about 18K. You could always put a smaller pulley on your mopar alternator to increase alt idle RPM speed which should help output. Don't over run the max alt rpm limit.

    An alternator only needs as much capacity as the system is going to draw. I usually size them for max amp draw +5
     
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