The one and only Prius Plug-in FAQ!

The FAQ section on B-Mode has evolved nicely, thank you all. I have searched this blog and the manual, and noplace do I see a comprehensive explanation of how a driver can maximize his benefit by mastery of regen, engine, and friction braking. I am aware that if I brake lightly I will preserve my brake pads. Not sure over the life of a car if that amounts to fifty cents, and if I burn more gas by engine braking, it might even cost more. But I am not aware of the demarcation between regen and friction; other than skid marks on pavement, is there a signal that tells me my brake pads are engaged? At what point do I know I have transitioned from lightly braking to full brake pad braking, and what is the relative difference in charging performance among all three braking modes. A how-to tutorial for braking/charging would be a handy resource. If it already exists, someone please share it. Thx.

 

on the left side of the hsi is the line between power and regen. you'll notice the green bar moving to the left of the line when you let off the pedal, and moving to the right as you push on it. and when you can't see it at all, you're close to gliding. as you brake, you see the bar move further left as you push harder. when it gets all the way to the left, the friction brakes are coming into play. and when you drop below 6mph, it's friction braking. to me, it's not about saving the brakes, it's about more regen and better mpg's thereby.

 

Thanks. I'll check it out tomorrow. When driving, I normally have the "ENERGY MONITOR" screen on the display. Watching how the HSI works will probably shed light on:

and what is the relative difference in charging performance among all three braking modes.​

The thought occurs to me that auto insurance underwriters might start frowning upon PiP drivers who look at their dashboard as much as they look at the road!​

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When I handed over my 07 Prius to the kids as their pool car I installed a carchip and set the brake alarm to sound at what was supposed to be the threshold for friction braking. It seemed to work fairly well for learning to use regen.

Vehicle tracking and monitoring solutions for small business, fleets, teens, and hobbyists by Davis

that was a long time ago and I don't remember the settings. I do remember I had to update(flash) the carchip to use it with the Prius.

I suspect you could do this today with a scangauge.

 

Noplace have I found a good tutorial explaining the three buttons: POWER vs EV/HV vs ECO. The POWER button is self-explanatory (I call it my James Bond on-ramp boost). The car defaults to EV when starting out after a charge. I use EV for as long as it lasts, then spend the rest of the day in ECO or HV, whatever the difference is. I understand that NOT pressing the ECO button is the same as pressing it, once the EV charge is depleted. Is this so, and is there a difference in performance? When should one switch from one to the other?

 

you have two separate functions: ev/hv and power/normal/eco. use ev on back roads and flattish roads. you get the most bang for your electron there. use hv for highway and uphills, engine is more efficient. power/normal/eco is just throttle mapping. you have power mode correct, it takes less pedal travel to give you power vs normal. eco takes the most travel to achieve the same result (007) but throws in reduced heat and a/c to help save fuel. but the same power is available in all three modes, you just have to push the pedal to the metal.

 

Thanks. But what's the relative difference between HV and ECO?

 

Let me put it another way to elicit opinions from folks.
I leave the house in the morning in EV mode, usually with ICE running this time of year.
I drive 25 mph to 35 mph for about 2.5 miles and I'm on the Interstate. As soon as I get up to about 55 mph on the ramp the ICE kicks in and I switch to ECO for the next 100 miles at 75 MPH. When I leave the Interstate I switch back to EV mode if there is still a charge. If there is not a charge, I leave it in ECO mode. I drive a couple of miles to my destination, then return home. On the way home I will use up any EV charge that remains, then switch to ECO. Is this the best way to toggle the switches? Again, is there any difference in performance or gas mileage between ECO and HV? Thanks.

 

there is no relationship. hv is 'hybrid vehicle mode'. this means it will operate like a regular prius, and use very little of the battery for power as opposed to ev, which is 'electric vehicle mode'. which is all electric, no engine, except as noted.
in either of these modes, 'eco' changes the throttle response, making it more difficult to stomp on the pedal, effectively saving gas or electrons. i'm not sure how else to explain it, do you have a more specific question?

 

So if optimum MPG is desired, leave it on ECO all the time, regardless of speed, terrain, EV, or HV.

 

Yes. In my typical commute, as described above, am I manipulating the buttons properly?

 

As others have said, the ECO button and EV button operate independently.

If you want to maximize mpgs, the standard recommendation is keep it in ECO mode all the time, since it makes jackrabbit starts less likely (unless you stomp the pedal in frustration!), makes it easier to do glides and such if hypermiling, and makes the AC/Heat less aggressive (cutting power usage). If I was getting into a very hot or very cold car, I would turn off ECO mode till the temp was more acceptable. The throttle response is sometimes just too laid back for me, and takes more foot action. Not sure it's worth it to me, since I never saw huge gains from using ECO mode.

To maximize mpgs and efficient use of EV capacity, the standard recommendation is to go into HV mode when doing normal highway speed runs, so as to save the stored EV capacity for tooling around in lower speed, stop and go traffic. Running at highway speed in EV mode uses it up pretty quickly. Therefore, in your description above, add hitting the EV button right before entering the highway (to go into HV mode), and then again after exiting the highway (to go back into EV mode). [cringing, waiting for the techies to tell me I'm wrong]

 

yes! i'll say no more to reduce confusion, there is plenty of good info above. read thoroughly and formulate your next question if there is one.

 

All good. ECO deadens the throttle, that's all. ECO in EV makes the car feel like it's towing a boat, but it has plenty of zip in EV only. Also, it looks (and feels and sounds) like POWER mode sucks down the petrol. So I rarely engage that mode but for a few short on-ramps that I frequent. I call it my 007 Boost.

 

I bought another small compressor along with a tire plug kit.

 

Also, the air conditioner is fully electric. If you have the climate control temperature set to LO, turn on the fan, press the AC button, and direct the air to the windshield. Obviously, this isn't a great solution if it's already very cold out, and it won't work if the frost is iced onto the windshield. But if the temperature is moderate, it will defrost the inside of the windshield without starting the ICE.

 

Using regenerative braking amounts to a lot more than fifty cents over the life of the car. In the first place, it generates electricity, which saves you gas. Second, it saves your brake pads. Most Prius owners replace brake pads at 100,000 miles. One owner I know replaced his front pads at 100,000 and 200,000, and the rear pads are still good at 230,000 miles.

Second, all cars use engine braking. If, for example, you drive a manual transmission car and you drive down a mountain in Neutral, and you only use the brakes to slow down, the brake pads can overheat, which can kill you. With a Prius, the generator performs the job of engine braking, but when the battery is full, the generator can no longer slow the car down. The Prius engine must start, in order to provide engine braking. The B mode in Prius is the equivalent of the L1 and L2 gears you find on automatic transmission cars in America; when you use B mode, the car uses engine braking to behave as if you are in L2 gear, which slows you as you descend a downgrade.