[MetroMPG]

Problem with regen (aside from being difficult to implement on a series DC motor) is if you live at the top of a hill is you'd be regenning into a fully charged pack (assuming you charge @ home).

Ideally if you have an EV with regen, you want to live at the bottom of a hill, so when you're coming home with a low pack, you can top it up a bit before you stick it back on the charger.