Regenerative ('regen' for short) also know as Dynamic braking is a feature of a special electric golf cart motor called a 'Shunt' wound motor. As you are going down a hill with the golf cart or just letting off the gas, the motor will act as a generator charging the batteries. It feels as if you are pressing the brake pedal. Almost all late model golf carts now come with a Shunt wound motor and the regen system. You are usually able to find out if your golf cart has this feature by looking for a Run/Tow mode switch mounted near the batteries.