Alternator concerns and ?'s

Discussion in 'Electrical Systems' started by william, Jan 15, 2006.

  1. william

    william Veteran Member

    Jul 21, 2002
    Indiana,P.A. U.S.A.
    I'm running a stock 61 amp alternator on my 78Z, since last summer it seems that its been struggling to keep the battery up.
    The car has all the power creature features, plus a CD player.
    My Question is if i swap over to a 80 or 100 amp unit am i inviting a fire hazard with my stock wiring?
    Thanks in advance.
  2. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

    Read here:

    Are you sure your current system is up to par? Ground wires ok? battery cables are good? It doesn't sound like you added anything big (fans, efi, amps), so the 60+ should be adequate.
  3. william

    william Veteran Member

    Jul 21, 2002
    Indiana,P.A. U.S.A.
    Thanks for the link! Lots of info here!
    No, nothing wild was added to the car.
    Thanks Again!
  4. Mwilson

    Mwilson Veteran Member

    Im running the stock alternator and struggled with charging problems for a couple years running elec fan, elec water pump, finally replacing battery cables and steping up to a good 1000 cca battery really helped.
  5. Gary S

    Gary S Administrator Lifetime Gold Member

    Apr 14, 1999
    Bismarck, North Dakota
    I agree with Mwilson. Most people replace a perfectly good factory alternator with an aftermarket one that won't do any better than what they already had, when all they needed to do was make sure the system was in good shape.
    I used to have a loaded 79 Caprice that came with a 65 amp alternator. The alternator died, and all I had in my garage was a spare 37 amp unit. I installed that one and all the power accessories worked just fine even in the Winter when batteries are difficult to keep charged. Eventually, I repaired the 65 amp unit and put it back, but it didn't do any better than the 37 amp one. A few years later, I had a 85 Caprice that popped its 80 amp alternator, and again, the 37 amp spare did duty just fine for a few months powering the power windows, power locks, air conditioning, power antenna, radio, power seats, and everything a Caprice has. The 37 amp never came up short and eventually, I put another 80 amp unit back in that car.
    Today, both Caprices are dead and gone, but my spare 37 amp alternator is still in my garage to fix the next vehicle that needs help.
    Years ago, I had a 70 Chevy 4x4 with a 37 amp externally regulated alternator. I bought a lifetime warrantied battery, and when the battery died, I took it in for replacement. Of course, the shop wanted the problem to be something other than their battery so they wouldn't have to replace it. They load tested my 37 amp alternator, and it sat their on their load machine putting out a steady 65 amps until their load got hot. Yes, they gave me a new battery.
    Last edited: Jan 15, 2006

Share This Page