regen braking versus regular braking

The owners manual states that the B mode is used to charge the batteries when going downhill. But, if I use the brakes while in D mode, that also charges the batteries. So, what is the difference? Just wondering.

 

B gear does less regen, and engine braking. Toyota is vague in their description, but the consensus here is to reserve B for long downhills, when the battery’s likely going to be completely full, well before you reach the bottom.

Many owners never use it, no problems. The car will also implement engine braking once battery is full.

 

While in "B", the engine is rotating, but no fuel is used and no power to the injectors.
It's called "engine braking"

 

Just beware that on very tall hills, the automatic D-mode engine braking may be too light to prevent friction brake overheating. B-mode engine braking is considerably stronger.

On short hills, D with brakes gets you more battery charging than B. It may take a bit of experience to learn which hills are better left to D, and which will fill the battery regardless of mode, where you may as well shift to B at the start.

That is when gliding downhill on significant slopes. When using propulsive power uphill or on flats or near-flats, there is no difference between D and B, except that B will prevent engine auto-stop when you come to a red traffic light or stopsign.

 

That is good to know. I live near the Blue Ridge mountains. A few days ago, the icon for the battery showed "full". I was concerned that coming down the mountain might over-charge my battery.

 

Protection is built in to the ECUs and battery management system. Without such built-in protections, the manufacturer would not be able to afford the 100k / 150k mile battery warranty.