Power Box

Power Management Module (PMM):  Enclosure containing the charge controller and power switcher.
Short battery harness:  Connects battery to multiple battery harness or other load cable.
Short 5-pin/3 battery:  Connects primary and rechargeable batteries to PMM.
Battery harness connects 2:  Connects 2 rechargeable batteries together.
Battery harness connects 10:  Connects 10 primary battery packs together.
Battery harness connects 8:  Connects 8 rechargeable batteries together.

The Power Box is a combination of enclosure, solar charge controller, and connectors which ensure the battery is charged and the instrumentation is powered. Below are some pictures of the new PASSCAL power box (and below that is the old standard PASSCAL power box) . All the power boxes have a 12-15 amp load capacity and a Low Voltage Disconnect (LVD) to prevent damage to the battery. These boxes are designed to work with any nominal 12 volt solar panel and any deep cycle gel-cell lead acid battery.

The Solar Charge Controller is responsible to properly charge the batteries when solar energy is available.  The GenaSun GV-4 controller, which is used for summer only experiments,  is a very efficient charge controller that uses the MPPT (Maximum Power Point Tracking) to maximize the power available at the solar panel, increasing the efficiency by 10 to 30% over traditional solar regulators.  It also uses very little power in low or no light conditions.

PASSCAL's Polar Group specifically designed a power management module to control the charging and manage the power system in extreme-cold temperature environments. There are two main parts in the power box:  The solar charge controller and the power switcher.  The solar charge controller, as the name implies, takes care of the proper and efficient charging of the batteries when solar energy is available.  The power switcher takes care of switching from the rechargeable batteries to the primary batteries when the rechargeable batteries' voltage dips below a threshold, and switches from the primary batteries to the rechargeable batteries when the rechargeable batteries' voltage gets high enough from solar charging.  Both the charge controller and the power switcher were tested successfully for operation at -55C after having been subjected to -70C for several hours.