How to get the most efficient braking score

The most efficient braking is not using the brakes.

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Are you sure?

My cousin had a snow plow that didn't have brakes. He would always figure out something to plow into before he started forward motion. I'm unconvinced that's the most efficient driving approach in the long term.

 

I'm sure. If you can coast to a stop it is by far the most efficient.

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I'm sure. If you can coast to a stop it is by far the most efficient.

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I'm a new Prime owner and I'd also wondered about the "charge" region for regenerative braking and why my score wasn't that great when I kept the bar within the region (above the X in @'LectroFuel photo). I then stumbled on this thread. I'd seen the dashed line, but didn't think it corresponded to the charge area. I have been braking recently by trying to keep the charge bar aligned with this dashed line (when possible, of course). This does seem to keep the score high so far (limited testing). Knowing Toyota and the quality of the engineering, I don't think these scores are a gimmick--I'm sure there's good engineering behind it, just perhaps not communicated well enough (that always seems to be the disconnect). If the friction brakes are applied at the dashed line (unconfirmed) then maybe the rest of the bar is additional regen you get simultaneous with friction braking (I'm sure they're both active simultaneously to allow a "hand-off"). I also noticed that fairly slow consistent braking (when no one was behind me) sometimes doesn't achieve a great score (possibly less efficient to regen at a low electrical current?)

On a related note, I thought this plot and this plot and this plot might be useful to show. I'm pretty sure I saw the same one in some old Prius documentation (leading me to believe this is where it might have come from), but I can't find it now. I haven't seen any forum topics specifically talk about varying the brake force over time, other than a link to someone's personal study from years ago with constant brake pedal force to find the right force for maximum regeneration.

According to this graph, you want to start out braking pretty lightly. As you slow, you can increase your force, but only up to a point. Then, at very low speeds only the friction brakes are used. Also, fast initial application probably tells the computer you need an emergency stop and enact friction brakes, so that could negate this plot. This plot makes sense from an electrical viewpoint because hard braking (high decel) at high speeds would generate enormous current which the system couldn't handle. At moderate speeds, the same force (decel value) would generate moderate current, which could be handled. At near-zero speeds, the regeneration is not effective and is not used. So it seems that the quickest way to stop with full regenerative braking is by starting out with light application, increasing, holding steady, and then finishing out with the friction brakes. In my limited testing, aiming to keep the charge bar aligned with the dashed line seems to correspond to this idea. As for the OP (@dalcon95), try this dashed line technique (maybe with no cars around until you get the feel for the approximate, nonlinear, force application versus speed). I'm curious what others think.