I wonder if someone could give me a more complete explanation of the "B" setting of the gearshift. As I understand it, you put the car in B as you have a long glide to a stop (eg. approaching a stop sign or light) taking your foot off the accelerator and the brake. This uses the motor to brake the car and to charge the battery. So the purpose is to save on the brakes and to charge the battery? Is this all there is to it? Do you use it? Do you find it effective? Thanks in advance for your your response.

 

I have had two hybrids a 2004 Prius 60,000 miles and now the 2006 RX400h CPO 10,000 miles I only use the "B" coming down a long steep hill or in an emergency stop where I want the extra braking. Basically it acts as a jake brake on a truck does. I used it a lot on the Prius coming down Mount Washington. Rolling to a stop charges the battery also.

 

You can just leave it on B if your battery is low.

 

Actually you guys have it wrong. B is meant to be used when you need extra breaking like going down a long and or steep incline. It actually adds gas engine breaking and thus does not recharge your batteries as much as not using it. This is because your ICE is doing some of the breaking and it will decrease your fuel efficiency because you will not recapture as much electrical energy as you could have. This is especially true if you are using it in the city from traffic light to light where you definitely should not be using it.

The engineers put B breaking on the hybrids because the gas engine is not always running and by design with the continuously variable transmission when you take your foot off the gas you are free wheeling, no engine breaking on a hybrid when in drive, but regeneration of electricity is occouring. With a non hybrid you take your foot off the gas and the car slows down faster, id does not free wheel, if you down shift to a lower gear it slows faster yet, it's called engine breaking and on a hybrid it helps to use (engine breaking "B" ) it like in the mountains. In the mountains you should use it since on a long downhill slope the batteries will become fully charges quickly, the computer will stop the regeneration and with a free wheeling transmission you will need to use your friction breaks more and they could overheat.

Read your owners manual and Lexus pamphlet about how to drive and get the
most out of the Hybrid system. Their pamphlet is available on the Lexus website.