Electric Brake?

[JohnD2]

Hi. Gen 2 T-Spirit. I'm regularly in driving conditions whereby it's convenient to use the 'B' position to slow the car. Are there any bad effects of using this more often than only when descending hills. J

[Grumpy Cabbie]

Yes! It does little extra regen braking if any and actually puts stress onto the engine. B mode turns the engine into an air brake.

There is no regen under about 7 mph anyhow. Just leave the car in D (Drive), ensure tyre pressures are correct and drive gently for best mpg's.

[kithmo]

Are there any bad effects of using this more often than only when descending hills. J

It will affect your mpg, as it slows the car down more on the flat, meaning you have to accelerate more to get back up to speed.

[Grumpy Cabbie]

I think he was refering to that nonsense given out by some dealers that to put more charge into the Battery when you brake you should momentarily select B. It doesn't put more charge in and will put more wear on your engine and gear selector. It might look like you're getting more charge on gentle braking but on heavier braking it certainly doesn't.

B mode is purely for decending long and/or steep hills. Nothing more, nothing less. At least as far as hybrids are concerned.

An example is a hill near me. If I decend it in Drive then my HV Battery is fully charged by half way. If I decend in B then my HV Battery is unlikely to be full at the bottom.

[JohnD2]

I'm really glad I asked. Thanks for replies. I shall cease doing this as from now. J

[Grumpy Cabbie]

An example is a hill near me. If I decend it in Drive then my HV battery is fully charged by half way. If I decend in B then my HV battery is unlikely to be full at the bottom.

I forgot to say that that is a good thing as you don't want to over fill the hybrid Battery on a regular basis. The Prius will try and stop you and won't allow you to do damage as such, but saying that, you really don't want to worry it - so to speak.

[johalareewi]

I forgot to say that that is a good thing as you don't want to over fill the hybrid battery on a regular basis. The Prius will try and stop you and won't allow you to do damage as such, but saying that, you really don't want to worry it - so to speak.

If you are on a long downhill slope in D and the Prius decides you have topped the HV Battery up enough, it will automatically behind the scenes, use B mode instead of regenerative braking (plus friction brakes of course). It won't show as B on the MFD though. So yes, the Prius does look after itself

[Joseph D]

Here is a very informative article I found that answers the questions asked in this post:

It was written pre-Gen III, but for the most part the information can be applied to the Gen III too: "B" Gear Explained

[Dave R.]

I forgot to say that that is a good thing as you don't want to over fill the hybrid battery on a regular basis. The Prius will try and stop you and won't allow you to do damage as such, but saying that, you really don't want to worry it - so to speak.

If you are on a long downhill slope in D and the Prius decides you have topped the HV Battery up enough, it will automatically behind the scenes, use B mode instead of regenerative braking (plus friction brakes of course). It won't show as B on the MFD though. So yes, the Prius does look after itself

Funnily enough, I experienced this yesterday driving back from Sheffield to Manchester over the A57 Snake Pass (Gen 3 T-Spirit)- I'd set cruise control to 50mph and was steadily descending from the top of the peaks when I suddenly noticed engine noise - the Battery was full to the brim (yes, it IS possible to get all the bars on the Battery indicator lit), the eco light had gone out & the car had automagically switched to engine braking, Switch off cruise control - the engine noise stopped and the car speeded up.