I believe they are on their way out. Slow cranking, barely fires off. Took all connections off last night and cleaned them. There was one that was corroded a bit from acid leaking. Checked voltage with them disconnected, and they were both 10. 75 volts. Expected to find one lower than the other. Just under 14 when running, so I think the alternator is OK. Left a 2 amp charger on them overnight, and they read 12. 4 volts this morning. Still cranked slow and drained the voltage down below 8 after barely starting. I believe these are the original batteries and they're "maintenance free" (can't get the vent caps off). My buddy is an Interstate dealer, so I'm planning to pick up a new pair today.
How long of life have you other guys had from your original batteries? I guess they could be about 6 years old, and the truck has 135K.
How long of life have you other guys had from your original batteries? I guess they could be about 6 years old, and the truck has 135K.