Thoughts on "B" Engine Braking mode

Well, B Mode is good, when you go down a looooooooooooooooooooog hill, and you don't want to cook your brakes riding them down the hill. When they overheat, you lose them.

Otherwise, brakes are cheaper than the engine.

 

I have used "B" a couple of times and found no difference so I don't use it any more. I agree about downshifting vs. braking. I ride motorcycles and sometimes downshift and use compression when I come to a stop, particularly if I'm on a hill, but normally I try to do a lot of coasting to a stop with the throttle closed and downshift from an upper gear to 1st as I almost stop rolling. It's smoother, quieter, and seems more gentle on the drive train. Replacing brake pads on a motorcycle is quick, cheap, and simple.

 

Any hill that would fill the HV Battery and use the engine braking before the bottom, you should use B from the top.
Other than hills with more than 600 foot drop (2300 feet if it is a Prius PHV) there is no real reason to use B.

 

I'm going to agree with everyone here. I only use B on long steep descents as the increased RPM in order to slow you will wear your engine quicker. I use it more as a safety feature on a long descent for the following reasons:

1. It keeps me off the brakes, which results in less heat buildup. Even with disk brakes I'd rather avoid possibly losing braking power at the end of my commute as there is a relatively sharp turn for a highway around a blind mountainside.

2. It isn't as efficient in regenerating your battery as using your brakes. This is because it uses your ICE in combination with your electric motor to keep your vehicle at speed. While this seems counter-intuitive my drive at the end is a 7% decline for roughly 2 miles. Even on "B" I will often top off my S.O.C. indicator. While I know this is still only roughly 80% of my charge, I don't want to risk overcharging my battery.

3. I also see it as a nice safety bonus. On long steep declines people typically lightly hold their brakes the entire descent, which attributes to what I like to call "brake light blindness". If you are following someone for a long distance who consistently taps their brakes or holds their brakes, you are less likely to realize if they come to a sudden stop or slow considerably. At the bottom of my "hill" I see an accident at least once every two months, which I think can be explained by this (but seeing as how I never stop to ask what happened, I don't know for sure).

 

I only used the "B" brake while driving through the Rocky Mountains on the way to California, and it really made a difference on some of those really loooooonnnnngg downgrades! Haven't used it since, but it's nice to know it's there the next time I'm on a steep grade.

 

I use B mode at least once a week because I live on a mountain and sometimes I leave it via a long steep hill that's about two miles long. It makes a huge difference. Without it, I end up hitting 80% SOC before I hit the bottom and I end up having to use the friction brakes. If I start at the top, everything balances out perfectly when I hit the bottom.