Lufters

Hi,
Been a Lexus RX owner for over a decade. My most recent RX is a loaded 2012 AWD RX450h purchased over the summer. I'm extremely happy with my newer vehicle. I'm averaging around 28.5 mpg since I got it ....trying more than half the time to get the best fuel mileage. It's turned into kind of a MPG game when I'm not in a rush, lol. Trying to just run on electric in my neighborhood, etc. I've been experimenting and researching different gasoline. My preliminary results have show the best gas for MPG seems to be 91 octane ethanol free gas vs. 93 octane 10% ethanol gas. I'll keep everyone up to date on that. It's hard to find a concrete answer to this on the internet. I'm fortunate to have that option in the upstate NY Saratoga region where I live.

Here's my question, how much resistance does the electric motors give when braking? How much does it actually slow the vehicle down until the brake pads engage? I'm guesses if braking correctly and watching the gauge, you can get the car to slow almost to a complete stop with just the regeneration and no brake pads? Very curious.

Thanks, John

vlad_a

You can answer your own question with an experiment.
When braking, put the transmission into N. This will disengage regen brakes. Remaining braking force is the actual brakes. There is no way to use just electric braking, even though electric motors are more than capable of completely stopping the vehicle.

I've seen a hack on old hybrids where they'll fool the hydraulic brake pressure sensor into thinking more brake pressure was applied to force more regen braking.

Lufters

Yeah that's what I assumed. I would guess Lexus had to balance safety and regen. I would also assume they've got enough years of hybrid tech to figure the best balance of braking with current technology.