Regenerative Braking - D or B ?

B mode used engine braking in previous generations as well as far as I know.

 

i meant this thread, but we have a new president as well.

 

Hmm, had to look back two-plus years and four pages in this thread to see the bisco post this was a reply to.

Looks like bisco was replying to this:

and that was correct at the time (and hasn't changed in two years) when the car is a PHEV (Prius Prime or Plugin of gen 5).

The "Regeneration Boost" mode is described in the owners' manual for the PHEV models. It does not appear in the HEV manuals. The exact behavior of B is not identical between HEVs and PHEVs.

In either model, B will use engine braking when necessary (just as D will) to avoid overcharging the battery. It is not forced to use engine braking only, and will use some regeneration when the battery charge is low enough.

In the HEV, the B mode will immediately add a bias toward less regen and more engine braking, so it can be used on long downhills to reduce stress on the smallish HEV battery.

The larger PHEV battery does not have the same need to be babied, and the PHEV's B mode does not have to use engine braking as much (though it will, of course, still use it when conditions warrant).