A common design adage when it comes to caps is the almost universal "rule of three" it falls in in first aid ( three minutes with out breathing and so on) three miles before having to stop for the wife to pee, three hours and the move is too long... one of those odd truisms of life. so in the design world we look for a capacitor rated the closest to three times the DC input voltage, as both a safety and longevity factor. In relatively recent times, 10 to 15 years, many cut rate computer motherboard manufacturers had been going below this unwritten rule, and using "as rated" or as close to possible, caps to cut costs, only to have them fail in short order. Usually within a half year after going out of warranty, even though the electrolytic would bulge before completely failing. Never go less than double your DC source voltage, try to go triple, or as close as possible and you will do fine. It just one of Life's odd truisms like needing anti diarrhea medicine the most when there is no toilet available