Originally Posted by Mwilson
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.
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.