Before I take it to the mechanic, I wonder if you fellers might have some ideas what these symptoms might be caused by. My guess is it's heat-related because it starts fine when cold.
When up to running temperature, solenoid activates but engine barely turns over. If I wait 5 minutes, it cranks fine. I have noticed that when cold, it turns over slower than before.
Battery is less than 6 months old. Checking voltages before during and after cranking cold or hot, I don't see anything obvious...
Measuring at the batter posts, it's 13V when off, drops down to 10-11V when cranking cold or hot, 14-15V when running.
After failing to crank hot a few times, battery still 13V when off. Also drops to same 10-11V range while trying to crank.