What?

In my vehicles everything is connected to the battery when the ignition is on.

Suggest you trace the wiring.

 

OOPS! My statement does not apply in today's cars with regulated alternators.

 

No load is connected directly to the battery except the starter motor,

The drawing for my car shows a red wire from the battery to the "battery junction box" where more than a dozen fuses and relays power everything in the car.

 

OOPS! My statement does not apply in today's cars with regulated alternators.

Your statement has not applied since the first vehicle or machine with live electric ignition rather than stand alone magneto ignition came out in the early 1900's a near century ago.