[jshore]

I have a new 2004 Prius which I love. One thing that I am curious about is how gently I have to brake in order to have the car do as much of the braking as possible through the regenerative braking system rather than applying the brake pads.

Right now, I simply have no idea. For example, I could imagine that one might have to almost coast to a stop in order to get maximum efficiency or I could imagine that one could get maximum efficiency (or very close to that) even if one slows down pretty quickly...just as long as it's not real quick.

Does anybody have any idea which of these two extremes lies closer to the truth?

 

[frenchie]

I'm a 2001 Prius owner and I know regenerative braking efficiency has been improved on the 2004, so take my comments with a grain of salt, but I think I can't be really wrong.

Thanks to a Prius Mini-Scanner (unfortunately not available for the 2004 yet) I can monitor the amperage going into the battery during regenerative braking. There's a limit to this amperage which is about 60 A : if you brake more intensely, you will of course slow down more quickly but because you apply the brake pads, not because you generate more electricity. This is because the HV battery power is limited to about 21 kW, both for input and output.

But how much quick is it, since that was your question ? Well, much closer to the "coasting" limit than to the "pretty quickly" one... although I haven't done any precise measurements (I'll try to when I have time), let's say you can consider yourself as the chauffeur of a very rich old woman who asks you to drive her with maximum comfort to her bridge club and you'll have an idea of how smooth you must drive for best regenerative braking efficiency... :wink:

 

[jshore]

Thanks, frenchie. I'll try to keep that "chauffer for a very old rich woman" picture in my mind when I drive!

I think I am pretty good at slowing down gradually...although I have been a little confused by the smooth Prius ride making it feel like it is going slower than it is (in comparison to my previous Plymouth Colt). So, sometimes I think I have already slowed down quite a bit and look down at the speedometer and see I'm still going 25 or 30 and have to start braking harder!