would really like to know how to feel/hear the regenerative braking cutoff limits

I've ever heard or felt anything so the only thing I can offer is that you're running just the friction brakes when you're under 7 MPH and if you're at higher speeds and brake fairly hard you'll generate more electricity that can be stored in the battery. You'll need a scan guage to see when you're generating more than 80 or so amps, but you can hit that faily easily when your driving over 50 MPH.

Panic stopping also kicks in the friction brakes.

As a side note, it's a bit funny to think that when you're under firm braking that you're generating enough electricity to power your home at its peak load...

 

It's really hard to quantify it without added instrumentation. There is a certain amount of brake pressure considered maximally efficient, but without the instruments, about all we can do is use vague terminology like "moderate" or "gentle but firm." The "22 seconds from 45 MPH" guideline comes from someone who actually has studied and quantified regeneration, so that's probably the most objective method, though a little clumsy to apply.

Are you looking to brake most efficiently, or to drive most efficiently? The latter involves staying off the brakes as much as possible. Best is to use available kinetic energy, allowing the car to glide to slow down (search "pulse and glide" for more). Next best is regenerative coasting, with the foot off the both the accelerator and brake pedals. Less efficient is regenerative braking, and least efficient (of course) is friction braking.

 

I've noticed something with my Pri. I've experimented: when I soley take my foot off the accelerator, the car goes into charge mode (obviously) and I note a deleration rate of about 1mph every 1.5 seconds. But when I depress ever so slightly on the brake pedal - enough to make the brake lights come on), I notice an increase of deleration up to 2-3mph per second. I know I'm not pressing hard enough on the pedal to apply any appreciable braking force, so I presume the added deceleration is due to the regenerative braking kicking in. Further, when I utilize regen braking, the traction battery seems to charge quite a bit faster.

Check it out for yourself. But remember, when you step on the brake pedal, you step ever so slightly... hardly any pressure at all. You'll know your'e there when you see the car rate of deceleration increase - about double.

 

EZW1 has my method. Tap brake to start regeneration early when forced to slow down. Use brakes sparingly at turn of last few feet.

 

+1 to that!

I try and drive ahead of myself. When I know that there's something coming that I'm going to have to slow down for, I get off the Go pedal and try and get into a glide or regen coast. If that's not sufficient, light pressure on the break pedal usualy does the trick. Because I'm slowing down gradually, I've never worried about whether the friction breaks were kicking in.

This can be a challenge in heavy traffic. Traffic or no, always I let safety trump any other consideration, and do what I need to do to say safe. The difference between a friction or regen breaking becomes really archane if you hit something or someone.