A few photos of the Opal power control circuitry and batteries.
 
 

View of Opal power circuitry. One top is the current and voltage telemetry circuitry. The middle, silver boards are the voltage regulators. The bottom board is unused circuitry for attitude control. Opal has no attitude control system and this is not used.

One of the flight battery boxes placed on the flight honey comb tray.

This is the flight battery box uncovered. The black material is a potting, epoxy subsystem to seal the batteries from the vacuum of space.

Another view of the battery box and potting material.

View of Opal flight batteries prior to integration. They are NiCad battery packs providing a nominal voltage of 12V.