Check battery voltage at battery posts.
12.68v . . . . . . . . . . 100%
12.45v . . . . . . . . . . 75%
12.24v . . . . . . . . . . 50%
12.06v . . . . . . . . . . 25%
11.89v . . . . . . . . . . 0%
Maybe time to install Starter Relay to make sure you get maximum Battery Voltage at the Starter Solenoid
See item #7 of LT5 Added Systems