[billwot]

Originally Posted by Capt Spaulding

The explanation for the rapid click/weak battery phenomenon is pretty simple. When you turn the key to the start position the battery has enough power to energize the solenoid. Once the contacts in the solenoid close (click #1), the increased demand by the starter causes enough of a voltage drop that the battery can no longer offer enough power to keep the solenoid energized so the solenoid opens/releases (click #2). Once it releases, the battery is no longer being hammered by the starter and once again has enough power to energize the solenoid (click #3).

Exactly!