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Generator Pulley Size

Discussion in 'Early CJ5 and CJ6 Tech' started by Jrobz23, Dec 12, 2016.

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  1. Dec 12, 2016
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    Would running a smaller pulley help the low idle charging by spinning it faster? Has this been tried? I would assume so. I need a generator to run my hydro pump and plow.
     
    Last edited: Dec 12, 2016
    Jrobz23, Dec 12, 2016
    #1
  2. Dec 12, 2016
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

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    Good question, I would just put an alternator on it, for cheap, $70.00 or so, the bracket and the 5/8" pulley make it an easy up grade without really changing a lot, and you can keep your generator for going back. Mine makes 100 amps and I don't have anything that needs it. Good luck.
     
    Rick Whitson, Dec 12, 2016
    #2
  3. Dec 12, 2016
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    If you have the hilo pump that mounts to the generator you need the generator;)

    My uncle found a crank pully somewhere that had 1 normal size pully and 1 oversized pulley.

    Sounded like the thing was supercharged. I have the pully around here somewhere but i ended up taking it off. Think the pulley started to wobble.
     
    termin8ed, Dec 12, 2016
    #3
  4. Dec 12, 2016
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    Gonna be tough- the generator pulley incorporates the cooling fan blades.

    Also, spinning it too much faster could cause issues with the bearings.

    Are you idling so much that your battery is having issues?

    H.
     
    Howard Eisenhauer, Dec 12, 2016
    #4
  5. Dec 12, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I agree, I would definitely be worried about spinning it too fast. Obviously pulleys are sized to incorporate the whole rpm range, and I think generators are designed for lower rpm than a alternator. Of course if you did find a smaller pulley that would fit, never running it at higher rpms would probably be a fix. You could even adjust the throttle linkage so you could only open it to a certain amount.

    But in line with Howard's question about idling, is that the problem?
     
    Glenn, Dec 12, 2016
    #5
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  6. Dec 12, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Ditto the above - what is the real problem?
     
    PeteL, Dec 12, 2016
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  7. Dec 12, 2016
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    I do end up idle'ing and being at low RPM a ton. The Jeep mostly works, and does not spend much time on pavement (though that will be changing soon). I need to charge my battery with an external charger more often that I'd think is normal. I know the generator works, but how well is suspect, and I figured it was due to extensive low PRM use.

    I have dealt with superchargers and UNDERdriving accessory pulleys, like mentioned above. Overdrive, in theory, works the same way. This Jeep never sees > 3k RPM so why have a pulley sized for that when it hurts charging (is my thoughts)?
     
    Jrobz23, Dec 12, 2016
    #7
  8. Dec 12, 2016
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    Anything above 1000 RPM should give you full output- what's the voltage at the battery @ say, 1200 RPM?

    I'm thinking you may have a case of pre- '70 regulator trying to charge a post- '70 battery. Newer batteries want a higher voltage- 14.8 vs. 13.5 in the old days. After a while it will impact your battery performance.

    H.
     
    Howard Eisenhauer, Dec 12, 2016
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  9. Dec 12, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    It sounds to me like you need to take the generator to an automotive electrical shop and have it gone through. Maybe get the regulator checked also or get one capable of the higher voltage like Howard talks about.

    Personally I think you need an ammeter also so you can see what is going on with the charging system. That way you could watch the ammeter and tell when it's charging or discharging. I know a voltmeter is preferred nowadays but you don't get the immediate information like you do with an ammeter.
     
    Glenn, Dec 12, 2016
    #9
  10. Dec 12, 2016
    timgr

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    Or convert to an alternator. An alternator is more efficient than a generator, and makes a higher voltage at low speed. It's been done before to the 134s.
     
    timgr, Dec 12, 2016
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  11. Dec 12, 2016
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    Yeah, but bolting a HY-LO pump to an alternator is an exercise in frustration :D

    H.
     
    Howard Eisenhauer, Dec 12, 2016
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  12. Dec 12, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    How much does any F-head see 3000 rpm?:shock:
    Hardly at all. Your system was designed to work, and did for over half a century, just the way it is.
    The problem lies elsewhere.

    Are you sure your battery is not just old, weak, or failing?
    Is your fan belt tensioned properly?
    Generator brushes and commutator clean?

    Any of those could result in needing frequent "external" charges.

    As for alternators being more efficient? :rolleyes:
    The last new alternator had I burned out rapidly - and the replacement I bought carried a warning that it could be damaged "charging a discharged battery."
    There's progress for you.
     
    PeteL, Dec 12, 2016
    #12
  13. Dec 12, 2016
    termin8ed

    termin8ed I didn't do it Staff Member

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    If i remember correctly the generator doesnt charge untill IT sees 1000 rpms. Thats not engine rpms. Ive had this problem with wimpy and now with the trencher jeep. Maybe its an issue of adjusting the regulator but ive never been able to figure it out or had good luck with the generators.
    If your plowing anything like me it never gets spinning fast enough to charge.
    I "think" i saw the old pulley i had but not sure if i still have it. If i remember right the pulley was on the crank and was 2 inches larger diameter than the original. I think 1 inch bigger would work better.
     
    termin8ed, Dec 12, 2016
    #13
  14. Dec 12, 2016
    BobH

    BobH Member

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    generators don't charge well at low rpm. He needs to idle around at low rpm for periods of time.
    Baring any basic electrical problems, he has 2 choices, continue to charge externally or get an alternator. Or a third choice, drive it at normal road speed until the battery has a good charge on it then park it.
     
    BobH, Dec 12, 2016
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  15. Dec 12, 2016
    1960willyscj5

    1960willyscj5 Well-Known Member

    Mesa, Arizona
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    1960willyscj5, Dec 12, 2016
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  16. Dec 12, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    "55 mph is 3200 rpm on my tach."

    There you go… I never run mine over 50mph. Which would be 2909.09 rpm. :D



    F4DynoGraph600.gif
     
    PeteL, Dec 12, 2016
    #16
  17. Dec 12, 2016
    1960willyscj5

    1960willyscj5 Well-Known Member

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    It still is right at or just below 3k on the tach at 50 mph. They will do it. They were actually built to run at 60 to 65 mph with those 538 final gear ratios. I am just not running any faster thatn 55 in mine. Real hard to smell the roses at anything over that. And I want to run faster than the sidewinders and diamondbacks can strike, too.
     
    1960willyscj5, Dec 12, 2016
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  18. Dec 12, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    And of course generator type voltage regulators can be adjusted, or his could be failing.
     
    PeteL, Dec 12, 2016
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  19. Dec 12, 2016
    1960willyscj5

    1960willyscj5 Well-Known Member

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    Probably. I use an alternator on mine. Have to rev up to 1500 on the tach for the exciter to kick in, but then it charges at idle speed after that. And 1500 to 1600 is what my cold weather first start of the day high idle is set to.
     
    1960willyscj5, Dec 12, 2016
    #19
  20. Dec 12, 2016
    termin8ed

    termin8ed I didn't do it Staff Member

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    Can they be adjusted so they charge at idle?
    Ive never had one that did
     
    termin8ed, Dec 12, 2016
    #20
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