Hi,

I'm curious about the effect of shifting to Extra Braking on the 2004 Prius on the amount of regenerative braking energy captured. Does anyone have the answer? I assume that regenerative braking (battery charging due to deceleration) is active on the front wheels only. If one shifts to Extra Braking from Drive, the deceleration is increased; is this converted to battery charge also? If it is not, it would have a negative effect on fuel efficiency. On a ICE vehicle, 'downshifting' deceleration is absorbed by the ICE.

Haha. Who told you B stands for Extra Braking? It's certainly not the case! B is Brake mode, yes. But it's Engine Braking. Use it going down steep mountains, etc, so you don't heat up your pads. For everyday use, there isn't really reason to use it.

The B mode has about the same amount of regeneration as normal braking under some circumstances, though with normal braking you can use enough pressure to almost always generate more (if you know how). So, unless you're going for hyper-mileage and ever tenth of a point matters, don't worry about it. D will be better most all the time. And if you're going some place steep, B won't really kill your mileage.