Renewable Revolution

What happens when Tesla Model S's battery is full and it is going down hill?  John Gustafson, Tesla owner since 2011

This is a really good question, and it affects not only Teslas but hybrids like the Prius that use regenerative braking.

When the battery tops off, regenerative braking is disabled. On a Tesla (any model), a warning light appears on the display, because the driver needs to know that the feel of the brakes is going to be different.

With no energy being taken out of the car through the electromagnetic damping of regenerative braking, you suddenly need to press the brakes like you would on a typical non-EV, non-hybrid car, because you are actually using good old-fashioned friction to slow down the car. Disks and brake pads. It can be disconcerting if you don’t notice the warning on the display because suddenly having to press harder on the brake makes you feel like your brakes are failing, though of course they aren’t.

All EVs use regenerative braking first, but if the battery is full or if you brake hard, the conventional braking system kicks in.