8, i have no issues whatsoever with your doubt. mof, i can only encourage it, being contrary type of person myself. it's all good. one thing i know, and know for 100% - NOTHING and NO ONE can be trusted. period. but this is more for a philosophical forum, right? you ever read my signature here?

anyhow, does B mode recharge battery faster? yes. i just witnessed this this morning, driving to work. i seldom use energy screen, but had it on, stabbed by this thread. 9% 1 mile downhill put 2 bars onto battery status, and full charge by the end of the hill, with 75% of it in B mode. this is, by py observation, much fater charging than during regular drive or even rolling with inertia.

 

Yes it does, similar results when I went down a 13% downgrade in the B-mode near the top of the mountain. That turns into a 10% grade as you go down then 8% and less farther down.

I remember my engine revved 4000, 4500 then around 4800 once the traction battery hit 100%. I allowed the engine to rev or maybe a minute and it was very noisy, I shifted back into drive. That's when I found the physical (corolla size) brakes didn't want to slow the car, but I was up around 65 mph at the time. At that point I was in the foothills and the speed limit was back up to around 60 mph. That's when I made my mind up to learn to work with the regenerative brakes, and only use the B-mode on short steep grades.

I find that many of the mountains near where we live have 1 mile long runs at 5% grades, then slow to 45 for a curve, then another mile and curve. Going down I try to drive 50 best I can then slow gradually to 45 and let off the brakes. This slows the brakes charging the battery.

A toyota tech once told me the traction battery normally charges to 80% to allow the extra 20% for the regenerative braking.

 

Frictional braking and engine braking, compression and FRICTIONAL (4500-4800 RPM....), have the very same effect insofar as regeneration is concerned.

Both will SUBTRACT from the level of regeneration available in a given situation.

 

Regarding undersized "brakes"..

Weight is BIG factor for hybrids, and since it is expected that the frictional brakes will be used less than otherwise, "normal", the rotors could be thinner and not really have an adverse effect.