Even when the battery charge is empty, Prius Prime will continue operating in hybrid mode as long as there is enough fuel in the gas tank, so you don't have to worry about running out of the battery power while on a longer trip.
You should never drive Prius Prime without gasoline in the tank. While, under certain conditions, you may drive in EV Mode alone, the vehicle always requires gasoline to operate properly.
This helps compare the mileage of driving in EV Mode to the commonly used mpg figure for gas vehicles. So by driving Prius Prime in EV Mode, it has up to an EPA-estimated 133 MPGe. The Environmental Protection Agency (EPA) uses the mpg equivalent (MPGe) figure to convert the measurement of power used by plug-in hybrid vehicles, electric vehicles and others not powered by liquid fuels into something that resembles the more familiar mpg rating.
When fully charged, Prius Prime is rated for an EPA-estimated driving range of 25 miles in EV Mode before converting to HV Mode. Prius Prime will then continue in HV Mode until the battery is recharged.
Yes. In general, Prius Prime's performance will be affected just like a gas-powered vehicle. Extra cabin heating and other factors will use up electricity that could be used for driving, reducing EV Mode range. However, an electric heater has been installed inside the battery pack to boost battery temperature. This enhances EV mileage and drivability in cold temperatures and reduces engine startup during EV Mode. And don't worry, if your battery ever runs low, Prius Prime will seamlessly shift into hybrid mode to keep you going.