470 mF at 6 V — backup power hold-up sizing
The SCMQ14H474PRBB0 is a 470 mF supercapacitor rated at 6 V, part of KYOCERA AVX's SCM series. This through-hole radial can delivers a 500 mOhm ESR at 1 kHz, which sets the IR drop during a discharge pulse — for a 1 A load, the initial drop is 0.5 V, leaving 5.5 V at the load before the capacitance takes over.
Temperature and lifetime — 65°C ceiling, 1000 hours
Rated for 1000 hours at 65°C, with an operating range of -40°C to 65°C. The lifetime is specified at the rated temperature and voltage — derating both extends usable life, but the 65°C limit means this part is best suited to indoor or sheltered environments, not engine bays or hot enclosures.