B mode and regen

[Electruck]

I've had my RAV for a week now, and the thing I'm struggling with the most is braking.

I'm used to a strong regen slowdown from driving in E like on a Leaf, and feel like I'm going to be replacing my brake pads in a year with this vehicle. :/

I see there's better regen with B mode, so I've been shifting into it when approaching red lights. But the manual says B is for hills, and I thought my shifting days were behind me.

Do others shift to B to slow for stops? Or can I drive in B for mainly non-highway driving like I did with my Leaf (in E)?

 

[rickrides]

I drive in B most of the time when not using cruise control...Cruise doesn't work in B. Almost all my cars have been standard transmissions so I'm used to engine braking. I try to get as much regen as I can with my Rav4.

 

[n3ckf]

yeah i use B most of the time. that i can tell it makes absolutely no different other than cruise is turned off. So if i'm not in a situation where i want to use cruise, i mostly use B.
I have 25K on my Rav4 so far and brake wear is pretty minimal.

 

[BatteryRav]

You can use B mode at any time without worry. As others point out, the only caveat is that cruise is disabled in B.

As for brake wear - don't worry too much about it, because the car employs a brake blending strategy. When you press the brake pedal, the car is actually engaging stronger regen braking (you can see this on the instrument cluster). The friction brakes are not used heavily until the car is moving quite slowly, at which time the regen fades out.

 

[james]

I have been using B mode more. I find that it works better in stop and go traffic and under 40 MPH. I don't have to use the brake as much and I seem to get a little more range too. The other thing I noticed is that the ECO light goes out when I'm using B mode. Not sure if that matters though

 

[occ]

I use B and D and N interchangeably daily. I change to D on getting up to speed, then use B toward traffic or red lights ahead as a pre-cursor to using the brakes. I drive like this on daily commute and get ~3.8m/kwh. On long road trip on freeway, I'm only getting 3.3m/kwh. I think I would only get 3.5mi/kwh if I didn't use B at all. I'm so used to this, it feels like driving a manual ... kinda fun.

 

[hanta]

The other thing I noticed is that the ECO light goes out when I'm using B mode.

Does anybody know exactly what that little ECO light means?

 

[miimura]

The other thing I noticed is that the ECO light goes out when I'm using B mode.

Does anybody know exactly what that little ECO light means?

It means that you are in Drive and the power gauge is in the green zone before it turns white.

 

[Electruck]

As for brake wear - don't worry too much about it, because the car employs a brake blending strategy. When you press the brake pedal, the car is actually engaging stronger regen braking (you can see this on the instrument cluster). The friction brakes are not used heavily until the car is moving quite slowly, at which time the regen fades out.

Hunh! That's interesting.

Thanks for the responses! I've been driving in B and doing much better in ECO Coach, and my kw/m usage is improving. I really prefer the feel of braking in B, and am glad to know I'm not damaging anything by using it.

 

[jimbo69ny]

Your eco score will drop but thats just a number that doesnt matter. I wanted to see if I could climb the ranks if I stopped using b as much and use plain old regen breaking more and I have jumped tremendously. In the end as long as your driving and using either or both efficiently thats all that matters. Im just a little competitive so I wanted to see if I could get a higher score.

 

[davewill]

Another technique that works well is to use cruise control when you want to travel downhill at a steady speed. Cruise control will apply regen to maintain speed, and it will do it more heavily than even "B" mode. I have one stretch on the way to work where it works perfectly, feathering the regen in and out as the grade changes.

P.S. Yes, cruise also works to go uphill or on the flat at a steady speed, but it doesn't seem as efficient as maintaining speed yourself using the accelerator in those cases.

 

[miimura]

Another technique that works well is to use cruise control when you want to travel downhill at a steady speed. Cruise control will apply regen to maintain speed, and it will do it more heavily than even "B" mode. I have one stretch on the way to work where it works perfectly, feathering the regen in and out as the grade changes.

P.S. Yes, cruise also works to go uphill or on the flat at a steady speed, but it doesn't seem as efficient as maintaining speed yourself using the accelerator in those cases.

I found that the cruise has the same regen limit as B mode. I tested this by going down a hill long enough and steep enough that the car was gaining speed with the cruise control set. Then, engage B mode, which cancels the cruise. I found that the regen had no discernible change in feeling or on the purple bars on the gauge.

 

[TonyWilliams]

Another technique that works well is to use cruise control when you want to travel downhill at a steady speed. Cruise control will apply regen to maintain speed, and it will do it more heavily than even "B" mode. I have one stretch on the way to work where it works perfectly, feathering the regen in and out as the grade changes.

P.S. Yes, cruise also works to go uphill or on the flat at a steady speed, but it doesn't seem as efficient as maintaining speed yourself using the accelerator in those cases.

Have a really steep "test hill" near my house, and I can read out the actual amps going in and out of the battery.

Gotta go test this theory!!!

 

[jimbo69ny]

LIKE ^^^^

 

[yblaser]

I found that the cruise has the same regen limit as B mode.

My, albeit limited, experience has been the same as davewill. I'll be interested in hearing Tony's results.

I've also noticed that you really need to be in B-mode to get the maximum regen when using the brake pedal.

 

[Kohler Controller]

Last month I had the opportunity to take BMW up on their "3 day test drive" of an i3. I drove the REx version for 250 miles. Very nice vehicle, and with very aggressive regen (no D or B settings, just B+++ when you remove your foot from the accelerator). Many early BMW Active-E owners talk about one pedal driving and it has been incorporated into the i3. This is great for city use, but is really annoying on high speed runs. Which leads me to introduce a new concept that I would like to see EV's incorporate: Proportional (Accelerator liftoff) Regen depending on speed.

During my morning commute with with stop and go traffic, I prefer to drive in B so that I don't have to use the brake pedal as often. But on the highway, I prefer D (or even coast "N" if possible) to aid in gliding as heavy regen at higher speed is noticable, especially for the passengers.

So I would like new EV designers to incorporate a regen scheme that gradually increased regen as the speed drops. At first it could be crude as simple steps, like >60 mph = No regen when no pedals are touched, 45-60 mph = 20% regen, 25-45 mph = 40% regen, 10-25 mph = 60% regen, 0-10 mph = 80% regen.

Obviously, they could smooth it out so there aren't any steps or jolts as one slows down without any pedal touch, but you get the idea.

I would say the i3 has (accelerator liftoff) regen set to 80% regen all the time, regardless of speed, while the RAV4EV is about 20% in D and 40% in B mode.
I know some cars, like Tesla, can program their regen strength, but it's not proportional to speed.

I love the regen strength I get from B mode Braking, but not B mode Accelerator Liftoff when I'm not in slow traffic. Being able to select/choose/program brake regen versus accelerator liftoff regen would be a nice first step, with speed proportional regen being next.

 

[TonyWilliams]

I found that the cruise has the same regen limit as B mode.

My, albeit limited, experience has been the same as davewill. I'll be interested in hearing Tony's results.

I've also noticed that you really need to be in B-mode to get the maximum regen when using the brake pedal.

The uber regen test is:

75 amps max in B mode
125 amps max with friction brake pedal application

The cruise control doesn't have any effect on these values


Acceleration is:

480 amps max
530 amps max Sport mode

 

[miimura]

Personally, the model I would like is to have paddle shifters or a Tiptronic-style shifter gate that will adjust the regen level. The German automakers understand the value of "sailing" as they call it and they have shown this concept. The e-Golf has three levels of driver-selectable regen, but I don't know if it goes all the way to zero.

 

[TonyWilliams]

Personally, the model I would like is to have paddle shifters or a Tiptronic-style shifter gate that will adjust the regen level. The German automakers understand the value of "sailing" as they call it and they have shown this concept. The e-Golf has three levels of driver-selectable regen, but I don't know if it goes all the way to zero.

Well, we could probably come up with a way to get selectable regen without friction brake pedal engagement. Certainly, 50 more amps over "B" mode is available, if we could get those CAN messages.

Or, otherwise trick the car into thinking that the brake pedal was applied.

 

[Kohler Controller]

75 amps max in B mode
125 amps max with friction brake pedal application

The cruise control doesn't have any effect on these values


Acceleration is:

480 amps max
530 amps max Sport mode

What is the current with accelerator off and with friction pedal application when in D mode?

How in the world can they rate the motor at 85kW/115kW (regular/sport) when you are seeing ~150kW/175kW respectively? I always wondered how they make a 4100 lb vehicle get to 60 mph in 7 seconds with a system rated at just 115kW. They were sandbagging.