Proper downhill braking?

Without knowing how much speed you're building up and how steep the hill is, it's hard to say what technique is "best." But you can ride the brake, just use it as you need it. You're using all electric braking so if anything you're recharging the battery as you go downhill. I tend to be kind of in the middle and I experiment, in that I roll the car almost up to speed then see how much braking I need as I go downhill.

There's also a discussion about the use of "regular" braking vs. engine braking here (it has some data):
"B" Range...What's Really Going On... | PriusChat

 

When going down a large hill (Sierra Nevada) I initially put the car in neutral to attain 65 to 70 mph, then go into D to charge up battery. When the battery is fully charged I try to conserve it and save the charge for uphill and flats. Since Route 80 is really a series of ridges, either uphill or downhill, then this process continues many times. This always gives me over 100 mpg driving either the PIP or the C.

 

I would think the more gradual the better, but I really don't know. The only thing I can think of that would make a difference is that if you let it speed up quickly at first, you'll lose more energy to air resistance than in the other case. Aside from that, it should be the same amount of energy that you're regenerating, depending on if the generator's efficiency changes based on its load.

 

Efficiency wise as the linked thread says, don't use B unless it's a crazy long hill and you need to blow off that extra energy, you get more battery regen from braking in D. Also, I remember seeing someone with a scanguage mentioning that the last 20-25% of the regen meter was friction brakes, meaning you max out regen breaking with the blue regen meter around 75-80% full.

Personally, I let it roll up to just a little over the speed limit on the coast down, but I make sure to slow it down with a nice long slow break before any stop comes up. With shorter hills around here my maximum speed is more often limited by how long it's going to take to stop when I get to the bottom then it is by the actual speed limit.

 

I believe 62 MPH should be the max speed in N. Anything higher and you are exceeding the RPM limits in the transmission.

 

TY but, the car does not have a transmission. I have used the same procedure on my 2005, Pip and Prius C.The 2005 had 105,000 miles on it when sold, a neighbor bought it and the driver may have at least another 15,000 on it and it is still going strong. Where did you pick up that belief?
I'm give credence to anything documented by Toyota. I'm just nitpicking on the transmission.

 

The car does have a transmission... as the name itself suggests, it transmits the power from the motor to the wheels.

62mph might be a little high according to Toyota documentation. They suggest you not use "N" while driving, but if you do, don't allow the car to change hybrid ranges while in "N". EG: If you are travelling at below 46 mph you should not accelerate downhill at faster than 46 mph while in "N". Same at above 46 mph, you shouldn't decelerate to below 46 while in "N". Anything in between is indicated to be ok.

 

Does this only apply to gen3?

Almost positive I've changed 'hybrid ranges' while shifting out of "N" before, just hoping no damage was incurred

 

I've only read it on the Gen3 forums... but that's because I don't visit the other one's. So I don't know if it's all or not. Sorry.

 

I’ve driven all my Prii downhill in the Sierra from 7000 feet with constant changes in gear selection and neutral.
I have never experienced any problems with any of the cars either in neutral or gear selection. All speeds within reason, of course.

 

This should apply to all generations, but with different thresholds for each generation and model series. For your Gen2, the limit should be closer to 42 MPH.

I would challenge the next-to-last sentence in that post:

"... Same at above 46 mph, you shouldn't decelerate to below 46 while in "N". ..."

I am unaware of any problem slowing down from above to below the threshold.

On the speeding-up direction, it depends. The normally discussed theoretical risk, overspeeding and destroying MG1, applies only if the ICE is not spinning and you roll up beyond the undeclared safety margin. If the ICE was spinning before rolling faster, or if you didn't roll up beyond the safety margin, the car ought to be fine.