When Driving on Battery Should engine come on?

First, that "B" does not mean battery. Unfortunately, many salespeople are still spreading that incorrect information. It actually means "Engine Braking", which is entirely different.

As for how long/far you can drive using only electricity, that is primarily determined by how much you draw from the battery-pack. 10kW is the tolerance. Exceeding that causes the engine to start and join in. The same is true when the charge-level drops below about half too.

Also, if heat is needed for either the cabin or the emissions system, the engine will start back up regardless of electric draw.

So yes, that was normal.

 

John's response is a good one, but I just want to expand on what "Engine Braking" is. It's basically the Prius' equivilant of "downshifting". It uses the engine to help to slow the car down. The only time that you should need to shift into "B" is if you are going down a relatively steep hill for a long time. Other times, it is actually harmful to fuel efficiency to drive in "B" (although, it doesn't hurt the car itself).

Most people on the East Coast of the US will literally never have a time when they need to shift into "B." Living in CT, I know that I never have.

 

<div class='quotetop'>QUOTE(luvmyprius06 @ Aug 7 2006, 12:02 PM) [snapback]299042[/snapback]</div>

Well, you're certainly not the first (and unfortunately probably not the last) to be misinformed by a dealer. In fact, "B" mode may win the prize for "Prius Component Most Often Bulls**ted About By Dealers."

The manual has a decent explanation, if you want to read more.

 

That might be true, but we do have some pretty mountainous regions nearby in Virginia. I also have a street near my house that engine braking might be useful on (the hill is so steep the houses look crooked). Then again, I'm tempted to store up the batteries by braking all the way down the hill. Anybody know which would be better for the car?

 

<div class='quotetop'>QUOTE(M. Knight @ Aug 7 2006, 12:06 PM) [snapback]299049[/snapback]</div>

Yeah. Your point about the battery charging is what made me say that you may never need to use "B" on the east coast. The reason people downshift at all is to avoid overheating (friction) brakes. Since the Prius uses regerative braking most of the time, you're not using the friction brakes when you're braking a lot. Engine braking only becomes necessary when the battery is full (so regenerative braking is no longer used) and you don't want to be using your friction brakes excessively.

EDIT: Yup. What Evan said. He beat me to it. It's only useful for both long and steep downgrades.

 

<div class='quotetop'>QUOTE(efusco @ Aug 7 2006, 11:05 AM) [snapback]299045[/snapback]</div>

whats the concerns of this item, "EV BUTTON" , good/bad, how does it effect factory warranty??
How many members are using this??

 

<div class='quotetop'>QUOTE(Norman H. Renehan @ Aug 7 2006, 10:03 AM) [snapback]299099[/snapback]</div>

Lots of members have it. Some use it a lot, some use it only once in a while. This is available in Europe and Japan, but not in North America. Interestingly, the software is, so if you short one pin in one plug to ground (many ways to do that), the EV mode will activate if the conditions are right.

Please bear in mind that the distance you can go is only a mile or so. Plus, the ICE will have to run to charge the battery back up. If used properly you can save some mileage, if not you can waste mileage. I use it to go around a large parking lot, going home from a store close to where I live and moving it out of the garage. Others use daily on their commutes.