Can’t get an alternator to put out a charge

Electrical & Ignition

  1. furious70

    furious70 Active Member

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    Does turning on the lights or heater fan change that pattern at 2000rpm steady?
     
  2. saylor

    saylor Senior Member

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    i didnt run the lights when i was doing that bit of test. i only ran the lights when i put FLD to BATT stud on alternator, which did not force any more output. ill have to do it tomorrow.

    at this point im probably going to get both these ALTs tested and then change my belt routing if both alts test out OK. my gut feeling is this belt path isnt spinning the ALT fast enough.
     
  3. 78Brougham

    78Brougham Deplorable FCBO Gold Member

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    For one thing you need to get a decent Digital Volt Meter and not just use the "el cheapo" one under the dash. You may have wiring issues through the few yards of wiring going to it.

    And please don't get the "coupon freebie" from Horrible Freight. Spend a few bucks and get a nice one.

    Make sure you have a good ground on the Voltage Regulator also. Those, and the electronic ignition boxes are very susceptible to poor grounds.
     
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  4. Gerald Morris

    Gerald Morris Well-Known Member

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    Your output voltage read from your voltmeter at your dash resembles mine. I too use one of FuryGT's VRs. When Idling at 500 rpm, which is where I set the curb idle, I see about 11.9 to 12 V. But when my idle increases just a bit, say, to 800 rpm, I see a nice ~13.5V and at 1000 rpm I see a good 14.2-14.5 V. Even on cold nights with headlights and ancient heater blower and wipers running, I get a good 14.2V when the engines angular velocity exceeds 1000rpm. I run the older, "roundback" single field connection alternator.

    You might buy a second VR and try it at this point. I also recommend you increase the size of your charging wire from alternator to battery to #8 AWG, and run it directly to the battery from the alternator. You then can tap the battery for your dash and starter relay in the usual fashion.
     
  5. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    You know Gerald I’ve been looking in on this and thinking my ‘67 was acting like this and it was the voltage regulator.
     
  6. saylor

    saylor Senior Member

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    aigh show n tell time pull up a chair.

    first, fcuking ZERTS! RIVNUTS! SERTS! whatever you may call them. holy crap who has been hiding these from me this whole time.
    20191215_103233.jpg
    my voltage regulator was mounted from PO (pre 2013) with 2 different size screws, the original holes were wore out. i took 2 of these bad boys and got me some new threads basically, and now both are the same size thread again.


    20191215_094825.jpg
     
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  7. saylor

    saylor Senior Member

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    20191215_095150.jpg
    i had to make a zerter tool to install them. get a screw that fits the zert threads. get a bunch of washers. stack the washers with an oversized nut in the middle - dont thread the nut to the screw it needs to be larger dia./not fit the screw. thats what the vice grips are holding on to, so the screw can turn inside the nut. push/tap whole mess into hole. tighten screw, and it buckles the zert and draws it in towards you. when it snugs up, stop, and unthread the tool, leaving behind the fastened zert fitting.


    thusly:
    20191215_102723.jpg
     
  8. saylor

    saylor Senior Member

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    so i took both alternators (new one from last christmas + old one off 383) to vato zone and tested them. both failed...

    they got another one carried over from across town and had it to me by 1030am. my vatozone guys like me they see me every weekend...

    DL7001 alternator

    anyways the replacement was a dual field. i remembered somewhere nacho said you can ground out the other field and adapt to the pre '70 wiring / VR setup.

    so i verified that with some interwebs searching, then did it meself - just took a metal screw and used the GND hole on the ALT body.

    Thusly:
    20191215_123646.jpg
    notice the ALT mounting location - you need a 3/4" long shim there or the ALT will wobbly on you.
     
  9. saylor

    saylor Senior Member

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    so, next i grounded everything with #14ga. piece wire with loop ends on both ends:

    BATT- to front firewall.
    BATT- to #1 exhaust stud on block.
    #1 exhaust stud on block to k-frame.
    ALT housing to front firewall same bolt as orange box ign.
    VR body to ballast resistor mounting bolt.
     
  10. saylor

    saylor Senior Member

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    pre-start: 12.6v (multimeter across battery posts)
    on el cheapo gauge:
    idle: 12v
    anything above idle: +12~14v. never went a spec above 14v.

    on multimeter:
    idle: 12.8v
    ~2000 r.p.m. 13.8v

    with stereo engaged at decently loud volume, in park, at idle, when the woofer fires off it kicks to 12.4 then back up . . .
    with stereo engaged at decently loud volume, in drive, at idle, at a stoplight, it starts dropping below 12v on the el cheapo gauge.
    i guess im gonna rig up some piece wire so i can see the multimeter while driving.
    i got scared sitting at a long light with the gauge at 11.5 and the needle jumps down every time it hits bass.

    but - it looks like im charging again, which is the good thing.
    car never got over about 195*. 70* ambient temp today. fans are faster you can hear them shift speed according to voltage.
     
  11. 78Brougham

    78Brougham Deplorable FCBO Gold Member

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    I'm afraid that's mediocre at best. Even at idle it should be damn near or at 14.2. I know my '67 Imperial goes lower but that's because there's a hundred bulbs lighting up across the stern. Lol. Btw How much power is that radio pulling? I know some of these new systems require you to run a huge cable all the way to the amp in the trunk.
     
  12. saylor

    saylor Senior Member

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    im pulling:
    mr. gasket fuel pump
    2x cold case 14" fans
    1000w crunch amp
    300w fosgate amp
    tuner/deck

    havent turned on the lights yet to see wht its gonna do. scairt.

    i do have a fused 0/2 (i think) either 150a or 250a back to the trunk/amps id have to go look.
     
  13. 78Brougham

    78Brougham Deplorable FCBO Gold Member

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    Picard-Facepalm.jpg
    :rofl:
     
  14. traintech55

    traintech55 Senior Member FCBO Gold Member

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    By chance what is the amp. rating on the alternators you are using? The 65 amp may be to small and you might need to change over to the 100 amp unit.
     
    Last edited: Dec 15, 2019
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  15. Gerald Morris

    Gerald Morris Well-Known Member

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    Yep! I reckon its the most likely culprit. These solid state VRs do their thing, and while all are very similar, they're NOT identical. My system keeps the battery charged well enough, so I'm not apt to replace my VR just yet. I also keep a 5 W solar panel on the back deck which trickle charges the battery in any kind of decent light. I figure my big Exide battery will be good for one more year's warrant-able service regardless.

    These old alternators did well enough for an AM radio, headlights,wipers and an AC/heater blower, IFF the thermo-mech VR they came with was up to par, but it would be chancy if one had to run long on a rainy winter's night. 60 amps is NOT a great margin for comfort even now, with the solid state VR working. I'm looking to upgrade to something capable of 90-120 amps. Several options for this can be had.

    I have a couple old square-backs I could rebuild with heavier duty stators and diodes, get a roundback core and do the same with that, or just buy a brand new Powermaster or TuffStuff alternator. One can get either something that still uses an external regulator, or a 1 wire sort, for some more $$$.

    Any heavier current alternator WILL REQUIRE HEAVIER WIRING THROUGHOUT THE CHARGING CIRCUITS IN YOUR CAR. I already have SOME provision for a modest increase in current; say, up to 80 amps, but beyond that I will want to go to whatever is suited to the current + 15% over. I always size over by at least 15%, as a good engineering practice.
     
  16. saylor

    saylor Senior Member

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    :p

    lets go there. i was just reading about denso 100a alternators, and theres a thread from stan, etc.

    i have the stock 60a reman duralast 7001 alternator.

    i already did ammeter bypass, bulkhead bypass, ALT<>BATT circuit, upgraded V/R, and grounding. its ready to upgrade to a larger output alternator.

    i have a dead core alternator here to trade in and everything, this can be next weekends project.

    whats the alternator i need to ask for?

    some interweb voltage/amperage/wattage calculator said 141 amps with what electronics i typed in as draw :/

    wew lads.

    - saylor
     
  17. Gerald Morris

    Gerald Morris Well-Known Member

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    THAT is QUITE THE LOAD! I run just 1 16" pusher fan in addition to the original stuff Ma Par put on my unit, and have removed the AC and AM radio. You DEFINITELY NEED A LARGER ALTERNATOR!!!! let's do the arithmetic together here, assuming 12 V since that's the nominal rating for our rides:

    Starting with the amplifiers, you have 1300W there, which, divided by 12V leaves us 108 1/3 amperes DC. Now, you run a pair of 14 inch cooling fans, each of them requiring ostensibly 6.85 amps. Let's be polite and round up to 7 each, for another 14 amps. Now, your Mr. Gasket fuel pump requires about 4 amps, and has an overload rating at 5, right?

    Soooo, we're looking at 108.333 + 14 +4 = 126.333 amps. You had best get Something from TuffStuff or PowerMaster rated for 150 amps, if you want to rock out with those big amplifiers. I get by with my LG StupidFoan and a USB powered Greentooth speaker for toonz myself, but "
    de gustibus non est disputandum" eh?
     
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  18. saylor

    saylor Senior Member

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    yup perfect thanks for the maths. the online calculatiabrator i found said 141amp, so . . .yes. by the time i do headlights and cell phone chargers and screen and whatever.

    your estimates are very close i agree on all of them, like on the fuelpump its a 5a fuse yes sir.

    i have been reading posts all night, and alot of them say late 80s - 90s caravan/dakota/truck alternator. then a bunch of other posts say toyota/land cruiser alternator.

    whats do i need ill order it right now i just dont know which one is the most plug and play. im not scared to change wiring i just need to formagulate a plan. where the hell is stan didnt he do this already?
     
  19. saylor

    saylor Senior Member

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  20. Gerald Morris

    Gerald Morris Well-Known Member

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    I too am CURRENTLY using a Duralast 60A roundback remake for my rig, but I DON'T recommend them for ANY merit except VatoZone's excellent warranty: if it doesn't work to your liking, they'll replace it sans charge. If you're as impoverished as I am, it will suit you, BUT if you can spare a few extra $$ up front, then I advise you to go with a TuffStuff like this:

    Performance Alternators #9509RDDP7 - TUFF STUFF Performance Accessories

    That's a 1 wire alternator, brand new, U.S. made, MEANT TO BOLT RIGHT ON TO YOUR MOTOR WITHOUT BULLSHIT!

    It doesn't get easier than that bro. You WILL need to enlarge your charging conductor to #2 or even #0 AWG for the 130A output, but a fellow who appreciates serious audio like you do will KNOW where to get high grade copper wire for high ampacity.

    I haven't seen Brer Stan's Luminous contributions for some daze here. Hope he's well.

    One last query, how did you arrive at the DL7552?
     
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