I have a 33 mile commute each way on the freeway. Initially, I would get on the freeway and put the car in HV mode on the way to work and back. This didn't' make sense because I would arrive back home with surplus electric charge. Next, I got on the freeway in HV mode all the way to work (33 miles) and then used EV mode all the way back. This still left me with some residual electric charge. Today I drove all the way to work on EV and then remained on EV mode on the way back from work until the engine kicked on (happened when the power gauge was at 2 bars). Is there any downside to drain the battery all the way in this manner? Should I have waited for 3 or 4 bars and activated HV then? If there is no risk to the battery I don't mind driving on EV mode until I'm completely drained and not worrying about it.