Once the engine is running the charging system should carry the current demand of all the accessories, with some capacity left over to recharge the battery. At that point the battery CCA becomes a moot question. The only time the battery would enter into the mix would be in case of a temporary overload which would exceed the capability of the generator or alternator to carry the current load.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!