Photogenic Professional Lighting AKB-1 Battery - Manual (Page 3)

Installation of the battery.
The battery may not be installed in the unit when it arrives. To install
the battery, remove the protective padded case around the unit. There
is a Velcro strip between the padded case and the unit housing.
Separate the Velcro strips and the housing can be removed. At the
opposite end from the display panel, there is a sliding door that must be
opened exposing a channel compartment for the battery. The battery
must be placed into the channel with the silver contacts toward the
opened door. Push the battery into the channel until you feel resistance
and the door can be closed. Place the housing back into the soft case
for protection.