Ok, here is the breakdown:
1998 Chevy Silverado 5.7 automatic
I am having a starting issue, meaning that sometimes it starts fine, sometimes it barely cranks over (usually at night when ive used headlights).
What I know: It is charging at 14 plus volts (sometimes as high as 16).
The battery (battery#1) was showing 12.5 with engine off just after episode of it barely starting. This battery is less than a year old but I took it in to where I bought it and they said its bad. they gave me a new battery (battery#2).
Battery#2 is now two days old and was working great but then started doing the exact same thing as the first one last night. My truck would barely start after I got home last night. I once again tested the alternator, and its putting out plenty of voltage and the battery is showing 12.5 with engine off.
This morning it started fine, which is wierd cause it barely started last night. so I took it to autozone and they put their tester on it while running and confirmed my alternator is good. I shut it off and they tested the battery. At first he says, “oh it says 100%charge but bad battery” then he says “oh now its saying 50% charge good battery”
I have visually inspected connections and all seem to be solid with no shorts or lose wires.
Could this possibly be a second bad battery? first one being less than a year old and the second one only days old?
Should I suspect something internal in the starter only getting a partial juice.
Could the alternator be putting out volts but no amps? The vehicle runs fine even with lights on. so Im disinclined to think its the alternator.
I have tools and an analog volt meter. Anybody have any troubleshooting tips?