After 25 years on the market, most people know what a hybrid car is—even if the only one they can name is the Toyota Prius. And battery-electric vehicles are simple: plug in them to charge the battery, and it will power the car for a few hundred miles.But what happens if a plug-in hybrid doesn't get plugged in? TL, DR: Nothing.More specifically, it continues to operate just like a regular hybrid.
For example, they may regain one to four miles of pure electric range while descending a long, steep grade. But overall, the plug-in hybrid that's not plugged in is a regular hybrid. It likely gets better fuel economy than a nonhybrid, but it almost always gets worse fuel economy than a comparable standard hybrid.