Why a supercapacitor instead of a battery? Supercapacitors accept and release charge much more quickly and can be discharged and recharged many more times—and with far less deterioration than a battery. The Mazda unit can accept a full charge in just 8-10 s. And although it can discharge in as quickly as 40 s (at a maximum rate of 50 A/14.5-V), the capacitor may take up to about 113 s when the load is at the minimum—about 18 A. The battery capacity is unchanged, because a primary factor is the requirement for worst-case cold start, which would not include a charged supercapacitor.