Regenerative Brakes

[Spiffster]

When heading back down to Denver from Keystone the trip is just almost completely downhill. In my last car I would use a lot of engine breaking on the way back to the city to avoid excessive break heat and wear. I read elsewhere on this forum that the car uses regen breaks when the brake pedal is depressed less than half distance. My question is this: When the battery is fully charged and the brake pedal is less than half depressed does the car then utilize the hydraulic breaks instead?

[lolder]

Yes. See page 210 in the owners guide. Use "L" for engine braking instead. It can be engaged at any speed.

[Spiffster]

Yes. See page 210 in the owners guide. Use "L" for engine braking instead. It can be engaged at any speed.

 

Good to know. Thanks for the quick response!

[seamusbleu]

This is a bit of a thread hijack, but not entirely, as it has to do with the regenerative brakes. If you just feather the brakes, the regen indication comes on dimly, but just a little more pressure to a lot more pressure gives the same indication. Has anyone read anything about what is the most efficient way to use the brakes as far as energy recovery?

[lolder]

Which regen indication do you mean, the circular arrows or the top "charge" arrow in the HVB window? the faster you are going, the more regen is available. Below 5 mph, there's none at all. Brake early and moderately (to get under 47 mph so the ICE shuts down) and reduce braking as you slow so that you can almost coast to a stop, traffic permitting. Steady light braking is the best. Hard braking at low speeds is the worst.

[seamusbleu]

I'm talking about the circular arrows. What I don't know is how hard you can hit the brakes before the actual brakes are added to or supplant the regenerative braking.

[lolder]

There's no way to know because the system is so smooth in blending. The hydraulic brakes are called for when the brake pedal is pushed harder and/or faster. With light to moderate planned braking, you probably never use friction brakes until under 5 mph. With proper use, you may never have to service the friction brakes.

Also, I just today confirmed that my FFH (built May 2009) has brake-throttle over-ride. When accelerating, either in EV or ICE with the accelerator pedal; when you push simultaneously on the brake, braking occurs and the acceleration is canceled including the ICE going to idle or shutting down. Toyota is just now with their recalls instituting this in the Prius

[EntropyAvatar]

Also, I just today confirmed that my FFH (built May 2009) has brake-throttle over-ride. When accelerating, either in EV or ICE with the accelerator pedal; when you push simultaneously on the brake, braking occurs and the acceleration is canceled including the ICE going to idle or shutting down. Toyota is just now with their recalls instituting this in the Prius

 

Are you sure about this last bit? I know Toyota says they will do this for new versions of other cars, but I've read that the Prius already had it. I mean, just like in the FFH, MG2 acts as both brake and motor. To me, just the way the eCVT works you'd have to have an override as part of the basic design.

[lolder]

The regen and EV acceleration mode already do it by design but apparently not the ICE acceleration mode and that's what they're adding to the Prius. I am not 100% sure of this info. If you take the FFH and accelerate briskly with the ICE and simultaneously put on the brake, you will hear the ICE die down or stop.