(Not sure if this belongs in Elio Drivetrain (for possible future versions). Plz move if this belongs in General Discussion.) Sounds like 48V lead-carbon hybrids could be a cheaper and simpler solution than a full NiMH or Li ion hybrid. http://www.hybridcars.com/48-volts-hybrids-are-focus-of-the-week/ http://www.hybridcars.com/48-volt-cars-available-by-2016/ This is most a fyi posting. Something to keep an eye on.