Regen braking has become more aggressive?

I'm wondering if anyone has any thoughts on why the behavior of the regenerative braking seems recently to have changed slightly in my car.

I'm no expert, but I think that's what I'm observing. However, to be more precise, perhaps it's not "braking" as such, since what I'm observing doesn't happen when I'm pressing on the brake pedal, but rather when I completely let off the gas and have neither pedal pressed. Still, I notice on the display that, in these circumstances, power is being regenerated and stored in the battery.

The differences I've noticed are these: the regen braking seems to "grip" (for want of a better word) more abruptly as it starts to slow the car; the slowing happens more rapidly; the noise is louder; there may be a little bit of vibration. This is most noticeable at freeway speeds, and only when I let my foot off the accelerator entirely.

None of these symptoms is particularly marked. For instance, I say that it's louder, but it isn't "loud" per se. The change is not significant enough that I would necessarily think something was off if I were driving the car for the first time. But I've been driving the car long enough that I can sense something is subtly different than it was.

Two other things that may or may not be relevant:
1. The temperatures have recently dropped, though they are still above freezing.
2. I recently got a new catalytic converter, since the original was stolen from my car. I don't believe I noticed the change right after the replacement, but only now after a couple of weeks.


I appreciate your time, and any advice you might be able to give.

Erin

2009 Prius Touring

 

Thanks for the reply, PriusCamper. I'm glad it's not obviously a sign of something failing...!

I just find the behavior a little irritating, as the initiation of the slowdown feels less smooth than it did, and it made me worry that maybe the electric motor was working harder than it needed to or something, even though it doesn't feel any different than I'm used to when I accelerate from a stop, for example.

I use B mode on a hill every day right after leaving the house, and I don't remember anything feeling different today. I'll pay close attention tomorrow and see if I notice anything.

I have noticed the MPG drop a little, but I think it's typical for the colder weather.

 

Don't think I've left it in B accidentally; I am always mindful to observe that it goes back into drive as intended. I can feel a change in how the car behaves between the two modes, and I also look at the indicator on the dashboard display for confirmation.

I have never tried to use cruise control, and so I did wonder if I could have accidentally engaged it somehow. However, I learned that "cruise" will appear on the dashboard display when cruise control is engaged, and I have never observed that happen, so that would seem to exclude the errant cruise control idea.

 

This may be my favorite theory so far, PriusCamper. Certainly the mind has a way of drawing conclusions that aren't warranted. I suppose the absence of floormats allows a little more vibration to reach your foot, which the mind may well take as suggestive of a more powerful engine.

Still, I can't 100% discount that I felt the car slow more quickly on the freeway when I let off the gas. Possibly it was road conditions, the fact it was quite wet; the feeling, I could say, was somewhat analogous to driving through a large puddle. Still, this wasn't my first time driving in damp conditions here in Western WA, so I don't know why my mind would have registered something unusual.

I drove the car around town yesterday and today, and I did not notice anything that made me concerned. Maybe it was all in my mind, after all, made nervous by what recently happened with the catalytic converter (people doing a hack job and organ harvesting my poor car; part of me is afraid lest she never be the same again).

I'll probably have occasion to take a lengthy drive on the freeway later this week, and, if nothing seems out of the ordinary, I'll try to let the worry go.