How are you getting 920 cca? That requires a professional load tester, but it's a test for the capacity of the battery. A discharging battery is due to a failed charging system. To verify that you need to measure the battery voltage while the engine is running. It must be between 13.75 to 14.75 volts. If it is low or is staying near 12.6 volts, the generator is not recharging the battery while driving.
Thursday, February 7th, 2019 AT 6:39 PM