Electrical Diagnosis questions

Discussion in 'Mechanic and Repair' started by ArchZangel, Jul 6, 2005.

  1. ArchZangel

    ArchZangel LawnSite Member
    from Florida
    Messages: 24

    For all u mechs out there. I worked on a Scag today. FH680V (23 Kaw) Came in for a "no crank problem" Turned out dead battery. Checked starting system. All good there. Checked charging system. Now if I am not mistaken. The regulator needs some voltage to work at all. Charged the battery and still showing nothing over 12.5. What I am asking is an affirmation of my diagnosis. I charged the battery enough to start the engine on its own. But yet it shows barely any charging. Low to high idle. 12.5-12.8 Put a new battery on and voila charges from 12.9-13.6 from low to high. A battery can be so dead that it takes no charge? Yet still had enough "surface" charge to start the engine? Oh it's maddening. OIh and get this it was a blown fuse that kept the battery from charging in the first place. I replaced it. i tested the mower for a while. When I was done, man that fuse starting melting already. Would dying electric clutch cause such draw, or ya'll think it just might be a crappy connector arcing? Sorry for all the questions but the whole thing is crazy.

  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

  3. khouse

    khouse LawnSite Bronze Member
    Messages: 1,465

    Anything over 12.6 is charging the battery so your readings after the new battery sounds good. I don't know about the fuse getting hot except a high resistance connection at the fuse holder itself. Does the fuse get hot when the clutch is disengaged?
  4. ArchZangel

    ArchZangel LawnSite Member
    from Florida
    Messages: 24

    Thanks for the respose guys. The owner took the machine back. He just "Had" to have it back. So I never checked to really see if the fuse got hot without the blades engaed. I did get to run it for 5 min without the clutch on and I felt no difference, still darn hot!. I gave him some fuses. I expect to see him back soon. The other fuse was slightly melted too, but not open though. The fuse holder replacement. Never thought they could cause that much heat. I was always like they do or do not work. Yes the clutch is adjustable. He did adjust it because he said it was slipping. I seriously doubt he has the required .012 clearence. Well thanks again gentlemen. Nice to meet u all!

  5. Redneckn

    Redneckn LawnSite Senior Member
    Messages: 294

    I have never felt like anything less than 13vdc was "charging". Also, I have had batteries that had a nice to look at voltage reading, but didnt have crap for amperage.
    Electrical problems are fun. I enjoy messing with that type of thing on a machine.

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