I wrote that. Yes, it's highly doubtful it is the traction battery, most likely an optional, more powerful 12v battery. Still, it's strange how it's listed with no information and I haven't seen that option available in any other market. Has anyone in any other country seen a more powerful 12v battery option?
I agree that it is likely a higher capacity 12v battery. The Prius (both PiP and standard hybrid) had problems with the very low capacity battery that came standard with the car. Unlike conventional cars, when the charge drops below a certain level, the control electronics will not boot up and the car will not start at all, even if the traction battery has a full charge. Many owners replaced the OEM battery with an Optima Yellow Top as soon as they took delivery in order to ward off this problem. It is more likely to happen under extremes of heat, cold, and age, so perhaps BMW has taken a cue from Prius owners and developed a higher capacity replacement (or optional) battery for extreme climates.
Also, the BMW USA Features & Specs page lists "Stronger electricity supply" as standard (http://www.bmwusa.com/Standard/Cont...i3/BMWi3RangeExtender/Features_and_Specs.aspx). I would assume BMW packages the higher capacity 12 v battery as standard for the US market, as it does with so many other items that must be individually specified in European markets.
