D, ECO or B modes

[Don]

I have a Kubota diesel garden tractor with a hydrostatic transmission. It has the go pedal and a brake pedal on the same side, operated by your right foot. As I discovered shortly after I bought it ten years ago, it's a bit of a pain to take your foot off the go pedal and use the brakes, so early on I got in the habit of just modulating the go pedal when I need to slow or stop - I never use the brakes

It has a very tight transmission. Forward/Neutral/Revers all on one pedal. You can be going full speed ahead and immediately spin the wheels in reverse just by modulating the one pedal. From a standing stop on a paved surface, it will actually do a wheelie if you stomp the pedal fully - Quite a feat for a 900 pound tractor . . . . over half a ton with the operator aboard

Anyway, the week we brought the first iMiEV home, we discovered that driving it in the 'B' mode is very similar to the tractor - Modulating the pedal gives you both 'go' and 'brake' in pretty much any quantity you need. True, you can't immediately back up like you can on the tractor, but if you pay attention to what's happening in front of you, you rarely ever need to touch the brake pedal until you're under 10 mph or so - It won't surprise me at all to find the brake pads on both of our cars will still be 'as new' when we hit 100K . . . . but then, for reference, I did sell a Toyota Supra I had driven for many years with 160K on the clock which still had the factory brake pads on it. My son bought it and he put another 25K on it and it STILL had the factory brakes on it when HE sold it, so you might guess I'm pretty easy on the brakes - I do 90% of my slowing by downshifting in any manual transmission car so the 'B' mode was designed just for guys like me

Anyway, between the wife and I, both of our iMiEV's are driven 100% of the time in 'B' mode - I have no idea how the car behaves in D or Eco - Never fiddled around with either. When you can return as much energy to the battery pack as the excellent regen system in this car does, using the friction brakes is really quite wasteful. If you've gotta slow, why waste the juice you burned getting up to speed with friction braking? The car supposedly has a 62 mile range - I can pretty easily drive it 75 or 80 miles at 45 mph with the A/C keeping us cool :mrgreen:

Don

 

[PV1]

Yep, hydrostatic is excellent for a tractor.

I've noticed that up until 10-15 MPH, all three modes have the same throttle map. At that point, ECO falls back to its semi-proportional map. I did a little driving in B mode tonight (weaning myself from the Tesla Roadster http://www.myimiev.com/forum/viewtopic.php?f=12&t=2822), and did notice a little more pep compared to ECO.

 

[misterbleepy]

Anyway, the week we brought the first iMiEV home, we discovered that driving it in the 'B' mode is very similar to the tractor - Modulating the pedal gives you both 'go' and 'brake' in pretty much any quantity you need. True, you can't immediately back up like you can on the tractor, but if you pay attention to what's happening in front of you, you rarely ever need to touch the brake pedal until you're under 10 mph or so - It won't surprise me at all to find the brake pads on both of our cars will still be 'as new' when we hit 100K . . . .

This really makes me want to mod my iON to get the extra 2 modes it is missing - I'm another driver who slows a regular car by coming down through the gears (and having to double-declutch on a few of my older cars)

 

[RobbW]

If you have CaniOn, just look at the wH/km readout

I wish I did. But you Android folks are keeping that sweet program all to yourselves! If there were an iOS equivalent, I would happily be gleaning all this data.

 

[Don]

If you have CaniOn, just look at the wH/km readout

I wish I did. But you Android folks are keeping that sweet program all to yourselves! If there were an iOS equivalent, I would happily be gleaning all this data.

Actually, Joe is a pretty confirmed 'Apple Guy' I believe - I think his first foray into the Android world was when he bought a cheap tablet specifically to use with Canion in the car. While a good used iPad can set you back a few hundred, an Android tablet can be had for $30 or $40. No need to lament about the absence of an IOS version. Thank goodness Canion isn't Apple only!

Don

 

[RobbW]

While a good used iPad can set you back a few hundred, an Android tablet can be had for $30 or $40. No need to lament about the absence of an IOS version. Thank goodness Canion isn't Apple only!

Accept I already have plenty of iOS devices that I could use for such an application. No need for me to go out and buy yet another device just for one app. While I agree that it's good Canion is not an Apple-only app, I will lament that it is not available for both OSes. I just find it hard to believe that NO ONE out there has developed an app for iOS that can provide access to the same data as Canion.

 

[RobbW]

Anyway, between the wife and I, both of our iMiEV's are driven 100% of the time in 'B' mode - I have no idea how the car behaves in D or Eco - Never fiddled around with either. When you can return as much energy to the battery pack as the excellent regen system in this car does, using the friction brakes is really quite wasteful. If you've gotta slow, why waste the juice you burned getting up to speed with friction braking? The car supposedly has a 62 mile range - I can pretty easily drive it 75 or 80 miles at 45 mph with the A/C keeping us cool :mrgreen:

While I haven't completely settled on one specific drive mode, I will admit that for the past couple months, I have been driving mostly exclusively in B mode. A big part of the reason was for the same reasons you mention about regen braking and rarely having to use the service brakes. Another big reason (and probably more compelling especially during my morning commute) was that I was getting tired of always having to put my coffee down in order to mess with the shifter. So, I decided to pick one mode and leave there just for convenience. I chose B mode because I could emmulate pretty much all the different modes (including N) by just modulating the go pedal.

But, like I said in my previous post, I was still always wondering if I was missing out on efficiencies by not using one (or all) of the other modes. That's what lead to my most recent experimenting with the different modes. Especially considering the fact that since I've been driving in B mode exclusively, I have been having a VERY difficult time getting the higher RR values after a full charge these past couple months. I used to regularly get into the low to mid 80-mile RR range. Recently, I've only been getting in the low to mid 70-mile RR range. I couldn't figure out what was causing the decrease in RR values other than possibly the fact that I was driving exclusively in B mode.

As an update to my post from yesterday, on my commute home after work, I decided to go back to my old way of driving in mostly Eco mode but running the gates up to N and then downshifting through the progressively stronger regen modes when coming to a stop. When I got into the car this morning after a full charge, my RR was above 80 miles for the first time in a long time (83 miles to be exact). So, now the question becomes was it driving in Eco mode during the accelerations from stops or running the gates when coming to stops that had the bigger effect on my RR improvement? Or both combined? If it was running the gates, I will be sad as it means I may have to give up coffee during my morning commute!

In any event, my purpose behind trying to maximize my efficiencies in my Meepster have nothing to do with financial savings at the charger. As was the purpose in buying the iMiEV in the first place, it was all about the principle of getting off fossil fuels as much as possible. Any financials savings are just icing on the cake for me but far from a compelling reason. As such, I have an unshakable gut feeling that I have a responsibility to drive my Meepster as efficiently as possible to further reduce my energy usage. If I can eek out even just a couple tenths of a mile more per kWh, I am compelled to try. Unfortunately, it is the suburban Chicagoland commuter environment that makes it very difficult for me to do so. But I will keep trying.

 

[Aerowhatt]

Anyway, between the wife and I, both of our iMiEV's are driven 100% of the time in 'B' mode - I have no idea how the car behaves in D or Eco - Never fiddled around with either. When you can return as much energy to the battery pack as the excellent regen system in this car does, using the friction brakes is really quite wasteful. If you've gotta slow, why waste the juice you burned getting up to speed with friction braking? The car supposedly has a 62 mile range - I can pretty easily drive it 75 or 80 miles at 45 mph with the A/C keeping us cool :mrgreen:

Don

If you get rolling at 35 or so and shift the car into neutral then slowly apply brake pedal noting how far you are pressing it from rest before getting braking action. Now do the same thing in drive and what you find is that all of the very significant braking before the same amount of pedal motion that friction braking came in while in neutral is modulated regen. Modulated by how far you are depressing the brake pedal (well before the point that friction brakes are engaged). With the added benefit of lighting up the brake lights while slowing. Where I live brake lights liberally used, save your butt (literally!)

I drive around town in D and sometimes E (on Sunday). Always get on the freeway in D and shift to E once up to speed (a lot less power variation while driving on the freeway in E, stretching range). I also coast in N quite a bit on the freeway, since I live in the valley and have gentle grades all around. Monday we went for a wonderful hike in the mountains and went almost five miles in N at 65 mph down a slight grade following a Semi at about 2 car lengths. Dropping into D for a few seconds here or there to keep from closing the gap. I never use B. It is too far from N and is far more likely to get my butt smashed! Why bother with B when modulating the brake pedal gets the same power generating results without risking my rear end by having no HEY YOU! indication that I'm slowing to the person talking on the phone behind me.

Aerowhatt

 

[RobbW]

I'm no engineer or physics professor. So, sometimes I have these "Hmm, I wonder..." thoughts but no real idea if they are legitimate questions or just plain idiocy. One of those questions I've had for a while with the iMiEV is this. Hypothetically speaking, let's say you have a perfectly flat, straight road that is 100 miles long. Would there be any benefit to slowly accelerating up to 65 mph (in Eco mode or whichever), bumping the shifter up into N, letting the car slowly coast down to 55 mph, bumping the shifter back down to Eco to slowly accelerate back up to 65 mph, and then keep repeating that process the whole time? Or would the power consumption pretty much average out to being exactly the same as if you had just maintained an even 55 mph the whole time?

 

[Don]

Anyway, between the wife and I, both of our iMiEV's are driven 100% of the time in 'B' mode - I have no idea how the car behaves in D or Eco - Never fiddled around with either. When you can return as much energy to the battery pack as the excellent regen system in this car does, using the friction brakes is really quite wasteful. If you've gotta slow, why waste the juice you burned getting up to speed with friction braking? The car supposedly has a 62 mile range - I can pretty easily drive it 75 or 80 miles at 45 mph with the A/C keeping us cool :mrgreen:

Don

If you get rolling at 35 or so and shift the car into neutral then slowly apply brake pedal noting how far you are pressing it from rest before getting braking action. Now do the same thing in drive and what you find is that all of the very significant braking before the same amount of pedal motion that friction braking came in while in neutral is modulated regen. Modulated by how far you are depressing the brake pedal (well before the point that friction brakes are engaged). With the added benefit of lighting up the brake lights while slowing. Where I live brake lights liberally used, save your butt (literally!)

Yes, I'm aware that you can modulate regen by carefully pressing the brake pedal and you get very little friction braking in the mix. But, it's much harder to modulate the brake pedal than the Go pedal because you don't have your heel on the floor to make incremental changes to the pedal pressure, plus 90% of the time I want all the regen I can get and I don't have to modulate anything to get that in B mode . . . . just release the pedal completely. Modulating a brake pedal under braking isn't easy, as your weight shifts forward which tends to increase your pressure on the pedal - Modulating the Go pedal is a snap and I'm very good at it, otherwise I wouldn't be getting 75+ miles of range while using the A/C

Brake lights? For 50 years plus I've been slowing almost all the time by downshifting which like the iMiEV in B mode, doesn't light the brake lights. I'm very conscious of what's happening in my rear view mirror and I've never been rear ended in my life. I come from a motorcycle background where you'd better be aware of everything happening around you and always ready to take defensive steps to avoid an the other guy who isn't paying much attention to his/her driving. It's 5X worse than it used to be thanks to cel phones - In a car, it's a fender bender, but on a bike it's your life. Personally, I like the fact that the iMiEV slows at a predictable rate (much the same as downshifting an ICE) *without* showing any brake lights . . . . but I'm watching my mirrors whenever someone is following me closer than they should be

To each his own - There are different driving modes because there are different drivers. I would guess that D or Eco will be best for 90% of drivers . . . . those who were raised driving automatics because that's what D and Eco were designed to emulate

Don

 

[Don]

I'm no engineer or physics professor. So, sometimes I have these "Hmm, I wonder..." thoughts but no real idea if they are legitimate questions or just plain idiocy. One of those questions I've had for a while with the iMiEV is this. Hypothetically speaking, let's say you have a perfectly flat, straight road that is 100 miles long. Would there be any benefit to slowly accelerating up to 65 mph (in Eco mode or whichever), bumping the shifter up into N, letting the car slowly coast down to 55 mph, bumping the shifter back down to Eco to slowly accelerate back up to 65 mph, and then keep repeating that process the whole time? Or would the power consumption pretty much average out to being exactly the same as if you had just maintained an even 55 mph the whole time?

It would give you much worse mileage than doing a steady 55

In my lifetime of observations, what you're describing is *exactly* the way about 75% of drivers with an automatic transmission drive every day - They are either accelerating (up to the point that they realize they are going a bit faster than they want) or decelerating (up to the point that they realize they are going a bit slower than they want) - On the gas for a spell, coast for a spell and repeat. Never a steady foot on the pedal . . . . either slightly accelerating or slightly decelerating almost all the time

What you're describing is how you can get an EPA rated 25 mpg ICE to give you a reliable, consistant 20 mpg, so no, it's no way to drive an EV. This is why a cruise control gives the average driver much better mileage than they can get my manually pressing the pedal

You can get better EV mpg's without a cruise control though. Decelerate slightly going up small hills and then very gently regain your speed on the downside of the hill - Better mileage than holding a steady speed up and down small hills. On flat ground a steady speed is most efficient and the slower the speed the more efficient it is

Don

 

[RobbW]

I'm no engineer or physics professor. So, sometimes I have these "Hmm, I wonder..." thoughts but no real idea if they are legitimate questions or just plain idiocy. One of those questions I've had for a while with the iMiEV is this. Hypothetically speaking, let's say you have a perfectly flat, straight road that is 100 miles long. Would there be any benefit to slowly accelerating up to 65 mph (in Eco mode or whichever), bumping the shifter up into N, letting the car slowly coast down to 55 mph, bumping the shifter back down to Eco to slowly accelerate back up to 65 mph, and then keep repeating that process the whole time? Or would the power consumption pretty much average out to being exactly the same as if you had just maintained an even 55 mph the whole time?

It would give you much worse mileage than doing a steady 55

In my lifetime of observations, what you're describing is *exactly* the way about 75% of drivers with an automatic transmission drive every day - They are either accelerating (up to the point that they realize they are going a bit faster than they want) or decelerating (up to the point that they realize they are going a bit slower than they want) - On the gas for a spell, coast for a spell and repeat. Never a steady foot on the pedal . . . . either slightly accelerating or slightly decelerating almost all the time

What you're describing is how you can get an EPA rated 25 mpg ICE to give you a reliable, consistant 20 mpg, so no, it's no way to drive an EV. This is why a cruise control gives the average driver much better mileage than they can get my manually pressing the pedal

You can get better EV mpg's without a cruise control though. Decelerate slightly going up small hills and then very gently regain your speed on the downside of the hill - Better mileage than holding a steady speed up and down small hills. On flat ground a steady speed is most efficient and the slower the speed the more efficient it is

Don

Got it! Thanks for settling my inquiring mind, Don. Though, now I feel a bit like an idiot for asking the question in the first place. But, then, how are you ever going to learn anything if you never ask, right?!

 

[JoeS]

Love this thread, as it's perhaps the epitome of "Different Strokes for Different Folks"!

Even though I now don't hypermile often, I'm still in the habit of kicking into N on almost every downgrade since I find it too distracting to glance down at the red needle to ensure it is perfectly located in the zero point. Incidentally, that "zero" needle location is NOT the same (lowest driving energy consumption point) as is Neutral if the heater or aircon are on. As I've mentioned elsewhere, nowadays I use B in the hills and in the city, but D on the highway (with liberal use of N), Eco if in town and I have someone in the car and am (distracted) talking with them, and I maintain the car's speed constant on long highway downhills by messing with all four shifter positions.

RobbW, to answer your question and quantify your driving efficiency, CaniOn is the *best* way to go. As Don pointed out I'm a confirmed Apple products guy (still have my 1984 512K Mac), but I bought an inexpensive Android tablet strictly for CaniOn - well worth it! The least-expensive approach I've heard of (but haven't tried myself) is to get a prepaid Android phone (WalMart?) and never activate it. It's the LX or MX OBDII adapter that costs more...

 

[wmcbrine]

I would guess that D or Eco will be best for 90% of drivers . . . . those who were raised driving automatics because that's what D and Eco were designed to emulate

I was gonna say -- all you guys shifting all over the place while driving must come from a manual transmission background. It's totally alien to me. The only times I've ever even used Neutral were in car washes, and once with an old gas car that stalled and had to be pushed back into its parking spot. On the i-MiEV, I've mostly just gone with Eco, because hey, it says "Eco".

 

[Aerowhatt]

I'm no engineer or physics professor. So, sometimes I have these "Hmm, I wonder..." thoughts but no real idea if they are legitimate questions or just plain idiocy. One of those questions I've had for a while with the iMiEV is this. Hypothetically speaking, let's say you have a perfectly flat, straight road that is 100 miles long. Would there be any benefit to slowly accelerating up to 65 mph (in Eco mode or whichever), bumping the shifter up into N, letting the car slowly coast down to 55 mph, bumping the shifter back down to Eco to slowly accelerate back up to 65 mph, and then keep repeating that process the whole time? Or would the power consumption pretty much average out to being exactly the same as if you had just maintained an even 55 mph the whole time?

I did a side by side. Same course same direction same speed on a Sunday in july doing what you described. Did two routes exactly the same one using the shift to neutral and the other just using a steady foot and leaving it in gear. I have canion screen shots of it but didn't post because it's frankly too much of a PIA. The results were definitive. In both tests the flat ground shifting back and forth saves 2% to 3% over just letting the mitsu do it's thing. However down a grade yields very different result. Neutral saves a lot of power over regen/throttle in that case. Just let it stay even or pick up speed a bit in N and then drop back into drive (No accel, no brake) to slow a bit and stay at the posted speed. Steeper grades use the regen full time to keep your speed manageble. Smoothly modulate it with the first part of the throw of the brake pedal instead of switching drive modes (smoother and also easier on the car systems).

I no longer use neutral on the flats much at all. Not worth the trouble for what it does save. Sometimes I will use it due to traffic logistics like I did a 5 speed ICE. Neutral when needing to coast a while before slowing to a red light or traffic congestion that sort of thing.

Aerowhatt

 

[JoeS]

RobbW, I moved your CaniOn and tablet comments over to the CaniOn thread. Sorry we got off-topic.

 

[tigger19687]

I can't seem to keep it in D or B all the time.
D doesn't have enough Regen.
B makes my passenger (my teenage daughter) hit her head on the headrest and then I get to listen to her complain or just be pissed at me all day.

I usually have it is ECO when she is in my 'i'.
B if I am alone, but the hard Regen bothers me and I am NOT good at Feathering the throttle well... maybe I just need more practice.
I do "shift" back and forth from Eco to B. AS I used to drive a Standard years ago.

BUT............. since my trip to work and back is short and I get to plug in at work free, I drive like I STOLE IT too !!

 

[RobbW]

BUT............. since my trip to work and back is short and I get to plug in at work free, I drive like I STOLE IT too !!

So. Freaking. Jealous!

 

[JoeS]

...Pedal position translates into current being fed by the controller into the motor, recognizing the 2-3 second time delay in initial acceleration. This current will decrease as the car gets up to speed and the pedal is held steady....

I wasn't comfortable with this last sentence and this morning briefly attempted to verify it. I only tried it in D so far. Within limits, the current drawn by the car for a given pedal position seems to be constant (as evidenced by the red needle) and the car seems to just continue accelerating until it reaches a steady-state speed balance resulting, I think, primarily from wind resistance holding the car back. The current does not drop, like I had said, so I'm wrong. I'm sure if the pedal was floored then it would cut the current back at the usual 81mph. Anyway, interesting to further explore this in all three modes, as well as see if there is additional current-dampening in Eco mode. Work in progress, and nicely quantifiable using CaniOn.

 

[PV1]

Not sure about D or B as I rarely drive in those modes, but for ECO, both of your statements have some truth in them. I noticed for the most part, throttle position equals a set current. However, the "zero" point does drift based on speed. If you balance the pedal for zero power, but keep gaining speed, the car will drift into regen slightly. The same for slowing down, except the car applies a bit of power. Not nearly enough to feel in either direction, but it shows on the dash.

Lately, I did do some driving in B on some windy roads. Maybe we should call it (B)oost mode instead? :lol: