Dennis Bertken spent nearly two decades researching why flashlights fail. His answer - Infinity X1 - is a light that carries two power sources so it never leaves you in the dark, and it has already sold more than 15 million units.
For 79 years Schumacher Electric has sold the same quiet promise - your battery will not leave you stranded. The bet now is that the promise scales from a dead sedan to an electric car.