Bought a Prius last week. Two questions.

A) There are conversion losses to converting rotation to electricity and then electricity back to rotation, so never using B or the brakes would be best, but most of us can't plan well enough to never need to slow abruptly. Regeneration is simply the least horrible way to disapate kinetic energy. So saying 'I am getting' lots of regen' is the same as saying 'I am not planning my drive well enough, yet.'

B) You can't hurt the car with B, it is just less fuel efficiant than not using B. And if you ever really do need B, it will still be there. (There are esoteric times when B is a hypermiler trick between 24 and 7 MPH. B can keep the ICE rotaing if you are decelerating for light you plan will change just before you get there, but you risk nailing someone who is running their red)

 

Re: Bought a Prius last week. Two questions. (I've researched the forum for answers.)

As for your second question, there are likely as many answers for that as there are drivers.. I tend to use "Trip A" to record each fill-up, and reset it each time... B I use for longer trips, and whenever I would like to measure something specific.

 

Re: Bought a Prius last week. Two questions. (I've researched the forum for answers.)

Hi John, I have had my Prius for about a month now and this forum has been invaluable in learning about the car. Lots of experienced Prius owners here who can answer just about any question you come up with.

I use Trip A to track my current tankful (still only on my second tank) and Trip B to track cumulative lifetime stats. The reason I selected A for current and B for lifetime was by accident; I inadvertently reset Tank A (by holding a certain button for too long) halfway through my first tank.

 

Search the site for more about engine braking. What the B position does is to use excess motor-generator output to spin the engine while not feeding gas to the engine. this is in lieu of using the motor-generator output to charge the traction battery. Bottom line is, for optimum mileage, you don't want to use B very much. Dragging the brakes is fine, because you're not dragging the brakes unless you're really pushing hard on the pedal; mostly, you're sending coulombs into the battery.

For the rationale, do the search. It's been explained here eloquently.

 

Re: Bought a Prius last week. Two questions. (I've researched the forum for answers.)

This. I will never reset 'Trip B'. plus told my bookkeeper to track all prius gas receipts in Quickbooks seperately ...

 

B gear wastes energy by spinning the ICE as a pump. Yes you see an increase in regeneration, but you would see the same increase if you press the brake pedal, without wasting energy in engine braking.

Use B gear on BIG hills. Otherwise forget about it.

Tom

 

Re: Bought a Prius last week. Two questions. (I've researched the forum for answers.)

I know you are excited. Congrats and welcome.

Just drive normally. B are used for engine braking when going down hill. Although it will not harm your transmission I think you just need to drive normally in the normal drive gear.

 

LESS regeneration going to the battery with B than with D. If I understand the other posts.

 

Here is some good information by Hobbit, one of our more knowledgeable Prius drivers: HSI

As others have said, only use B mode if you are descending a long steep hill with a fully charged battery, it really isn't good for much. I have noticed I can regenerate over twice as many Amps by proper use of the brake pedal in D than B mode does.

I enjoy having two trip indicators, if I'm on a long trip I set one for the entire trip and reset the other one each morning before I start out.

 

i wouldn't worry about brake wear... in my gen II i didn't have to change the front brakes till 128,000 miles..... if you are in a high traffic area, such as Los angeles, using B is more comfortable in traffic since the brakes seem to have a delay.. the only problem with using B in this situation is that you slow down much faster and cars behind you are sometimes not aware... making you a road hazard...

 

I don't understand why you are so eager to charge the battery by using the B so often when the battery still holds sufficient charges. If the battery charge drops to 30% or lower (or whatever the factory programmed level it is), the ICE will kick in to recharge it. What's the advantage to keep your battery charging state in 90%, 100% of the time??? Safety is the key. Drive it normally as you would and enjoy the ride.

 

Re: Bought a Prius last week. Two questions. (I've researched the forum for answers.)

1) B is not recommended because it causes u to lose to much momentum. if u need to lose that much, u r driving too fast for conditions. B mode should only be used on extreme hills or very slippery conditions. regen is a lose situation. the amount of power regained is no where near the amount of power expended to attain set speed.

2) Trip A is for the tank mileage, Trip B i use for daily resets (on the 2006, trip B is my "oil counter" since it does not have a maintenance log. of course, i guess i could just manually write it into the maintenance log provided but have not up to this point, but probably should.

i get all oil changes at the dealer but i only have to log into their website and check the mileage on the cars when the oil was changed last... so i guess i am lazy in that respect

 

Re: Bought a Prius last week. Two questions. (I've researched the forum for answers.)

I have been using Trip 2 for gas intervals. I do a lot of highway driving and have been recording mpg's at 50. I don't know about the B gear.