A camera frame assembly or other apparatus has a flash unit having a self-oscillating charging circuit. The camera frame assembly is used with a filmstrip and a battery. The camera frame assembly has a film scrolling chamber and a battery compartment joined to the film scrolling chamber. The flash unit is joined to the chamber, in the camera frame assembly. The flash unit has near and far battery contacts coupled to the circuit. The contacts define an active battery station within the compartment configured to receive the battery in electrical series with the circuit via the contacts. At least one of the battery contacts is biased inwardly to restrain the battery within the active battery station. A battery grip is disposed in the compartment exterior to the near battery contact. The battery grip defines a standby battery station that is spaced from the near contact sufficiently to isolate the standby battery station from the circuit. At least one of the far battery contact and the battery grip is biased inwardly to restrain the battery within the standby battery station.