Below are the American Solar Challenge regulations for the auxiliary (supplemental) battery:
8.2.C Supplemental Batteries
8.2.C.1
Supplemental, replaceable batteries carried in the solar car may be used to power: main power
switch, radios, commercially available electronic panel meters with internal batteries, cell phones, driver
ventilation fans (if solely used for driver ventilation), and the horn. Supplemental battery power may
be used to momentarily power the battery protection system (BPS) as defined by Reg. 8.3 to verify safe
battery parameters before energizing the main power switch. During a battery fault, in which the BPS has
automatically opened the main power switch, the supplemental battery power may be used to power the
battery fans per Reg. 8.4.D.
8.2.C.2
The supplemental battery used during start-up must also be used to power the BPS, BPS
Strobe, and BPS Fault Driver Indication under fault conditions. This supplemental battery must be
located in the battery enclosure.
8.3 Protection Circuitry
All batteries must have protection circuitry appropriate for the battery technology used. Proof is required at
Scrutineering that the protection system is functional and meets manufacturer’s specifications. Testing
procedures will be provided, and the protection system design should allow for such testing. All measurement
leads should be fused or current limited to less than 1 mA for non-isolatable sinks in the measurement circuitry.
All protection circuitry should be contained in the battery enclosures per Reg. 8.4.
8.3.A Definitions
8.3.A.1 Cell: The smallest available source of energy in the battery pack as purchased from a
manufacturer. A single electrochemical cell.
8.3.A.2 Module: The smallest grouping of paralleled cells easily removable in a battery pack.
8.3.A.3 String: The smallest series of modules that make-up the battery pack required voltage.
8.3.A.4 Protection Limit: The measured level determined to be adequate to protect from an event.
8.3.A.5 Active Protection: System in which measurements are constantly monitored and where
actions are taken immediately without operator intervention to open the Main Power Switch should a
Battery Protection Fault occur. Any protection faults will latch such that a manual clearing process is
required by the driver with the vehicle not in motion and only after faults have been verified clear by the
protection system.
8.3.A.6 Passive Protection: System in which measurements are monitored by the driver and where
action is driver controlled.
8.3.A.7 Battery Protection System (BPS): The system that applies Active Protection to protect battery
pack.
8.3.B Types
8.3.B.1 Li-Based: n/a
8.3.B.2 Supplemental: All supplemental batteries must have at a minimum Passive Protection for
under voltage where charging occurs remote to the solar vehicle unless they are primary cells. Active
Protection is required if charging is within the solar vehicle. No Secondary Lithium battery types shall be
used for the Supplemental Battery unless the Supplemental Battery is powering a commercially procured
component such as a cell phone or laptop and the Supplemental Battery was intended for this purpose.