Originally Posted by RFSchaller
A typical battery is about 25 amp-hours capacity. Cranking power is in the 100 amp range while avionics pull about 7 amps. Seems like the avionics load during a typical start is insignificant.
AMP hour rating is only slightly connect to cranking amps rating.
The cold cranking amps available is directly connected to the actual voltage of a batter at any given moment and the published rating is with the battery fully
With a low battery voltage on your car, it is entirely possible for head lights on or off to mean the difference between whether it will actually start or not.........