I've been trying to find the theoretical maximum resting car battery voltage so I can determine a good voltage threshold to trigger off in a car.
The threshold voltage must be above the theoretical maximum resting car battery but below the alternator voltage.
maximum resting car battery voltage = 13V alternator voltage = 13.5
Threshold switching voltage = 13.25V
In , it is 12.9V but optima is 13.1V and Ballistic Performance Components EVO2 Battery is 13.7V
 Denton, T (2012). Automotive and Electrical Systems. USA: Routledge. P186.
Obviously if there was a Ballistic EVO2 Battery installed example 1 would not function.
Any ideas what the most typical maximum resting voltage is in a car?