Page 1 of 1

Gear differences 2012 D, C, B

Posted: Fri, 28 Nov 2014, 21:35
by LauraiMiEV
I recently purchased a "new" (28 kms) 2012 iMiEV and our owners manual is missing (the dealer promised to find us one). I've done some searching online and in this forum to see what difference the gears really make. As near as I can tell there's no appreciable difference to range for "normal" (whatever that might be) city/suburban driving. On hills B might be an advantage.

I did a very unscientific test by driving the same 100 km route 3 days in a row in similar conditions. One day all D, next was C, today was B. I do not have any sophisticated measurement app so I rely on the range meter and the charge bars to see what's working best. I used 2 methods to calculate total range per charge:
1) actual trip kms + bars remaining * calc of km/bars based on actual trip kms.I found:
2) actual trip kms + remaining range

Basically it really didn't matter. The answer always came out to be 132 km (okay, D yielded 134 using method 2 above). This was driving about 70% on an 80 kph road and 30% in an area with lots of traffic lights. No aircon or heater.

So, is there really any difference in gear setting or is it driver preference?

Gear differences 2012 D, C, B

Posted: Fri, 28 Nov 2014, 23:42
by adelaide-ev
Hi Laura
Having driven my imiev for nearly a year I have found little difference in range with the different modes.
C is min regen.D is medium regen. B is max regenerative braking.
I don,t use D at all-find it a bit boring like driving an auto. However I am rarely in peak hour traffic where it might be useful.
I prefer to drive in B in stop/start traffic,winding country roads and down big hills as I feel more control of the car that way. More like driving a manual with the max regen giving more control.
I use C for coasting on the flat combined with very smooth driving to eke out a bit more range if required
Hope this helps and welcome to the “iMiev club”
Sally

Gear differences 2012 D, C, B

Posted: Fri, 28 Nov 2014, 23:55
by LauraiMiEV
Sally,

Thanks for the welcome - it's nice to be here.

Your description is pretty much what I guess I had expected. I was hoping I'd missed something and there was a cunning way to squeeze an extra 10 km out of the range. But it looks like it is not to be.

I actually prefer driving in B mode, probably because I've driven a manual my whole life. I like having the engine brake for me though it is a bit disconcerting when the car slows to about 20kph and the drag stops. Obviously the wizards who engineered the regen decided we wouldn't want it at such slow speeds.

Gear differences 2012 D, C, B

Posted: Mon, 22 Dec 2014, 21:27
by MDK
Hi Laura

This link might help - i Miev owner's handbook

Not the full manual, but it does go into the gear-selector differences, and charging tips etc.

I also don't know which model year it refers too, but the the car pictured appears to have 2012 wheels.

And it's for the US market so it talks about 120 Volt charging

Gear differences 2012 D, C, B

Posted: Mon, 22 Dec 2014, 22:38
by offgridQLD
Although the selector stick to your left looks like a traditional gear selector The word (gear) isn't really appropriate.

The Imiev's electric motor connects directly to what is essentially a diff with two drive shafts coming out each end. So it is a fixed single speed reduction with no changable gear ratio's.

Reverse just spins the motor in the other direction. Park is similar to a traditional Automatic and the three modes D,C,B have nothing to do with the gears it just send a signal to the controller to change its Regenerative braking profile. D is average regen braking, B is aggressive - strong regen braking and c is light regen braking.

You can more or less drive the car in any of the three regen modes and get similar consumption numbers though typically if your rolling down lots of huge hills - mountains B mode will hold you back more. D mode is a good compromise for general mixed driving and c mode might be nice for people who live in flat terrain and are able to drive at a steady constant speed as he pedal is less sensitive to let off regen so just just makes coast along without applying any regen easier

I use D mode $90 of the time and B on huge hills or aggressive stop start traffic.

Kurt

Gear differences 2012 D, C, B

Posted: Mon, 22 Dec 2014, 23:31
by LauraiMiEV
Thanks for the manual. It's almost the same car I have. I think the US model has a few differences. This model has eco mode where I have C (cruising?) mode.

I'm finding I prefer driving in B mode. I am pretty comfortable with the level of braking and so I know when to remove my foot from the accelerator to watch the gauge swing into CHARGE zone. I only have to brake once the car gets below 20 kph when the regen turns off.

It's pretty clear that none of my modes (D,B,C) make any difference in acceleration, only braking. I have to say it seems much ado about very little to me.

Gear differences 2012 D, C, B

Posted: Tue, 23 Dec 2014, 02:26
by Simon
It is good that they all have the same acceleration in all modes! I was surprised in my dad's 2010 in Eco mode to find it has restricted power even when you press the accelerator hard into the floor. Image

Gear differences 2012 D, C, B

Posted: Tue, 23 Dec 2014, 03:22
by LauraiMiEV
Simon wrote: It is good that they all have the same acceleration in all modes! I was surprised in my dad's 2010 in Eco mode to find it has restricted power even when you press the accelerator hard into the floor. Image


Oh, well, um.... confession... I never press the accelerator hard into the floor. So maybe it is just the same if you are a boring driver? Perhaps I'll take it for a spin and put the pedal to the metal and see if I still think the acceleration is the same.

Gear differences 2012 D, C, B

Posted: Tue, 23 Dec 2014, 04:32
by Simon
Oooh yes try it out. Image Pedal to the metal and watch the power meter. From memory it only goes about 2 thirds of the way around and stops in Eco mode on the 2010 model.

Gear differences 2012 D, C, B

Posted: Tue, 23 Dec 2014, 05:14
by carnut1100
I have a 2010 and my wife a 2012.
Eco mode on the 2010 sucks.
Wishy washy regen and a deadened accelerator response.

B on a 2010 is about the same regen as D on a 2012...D on a 2010 is similar to C on a 2012.

Biggest difference is that touching the brake pedal on a 2012 sends regen to max whereas the 2010 doesn't do that. Regen is controlled entirely by shifter position.

Gear differences 2012 D, C, B

Posted: Tue, 23 Dec 2014, 07:25
by mikedufty
Someone on another forum said the eco mode was good for people with long legs, it gives you more leg space because you need to push the pedal further for the same acceleration.
I tend to use B all the time to get some regen, sometimes use D when I'm too lazy to push the lever all the way down to B. I think the 2012 model gets some regen from the brake pedal, so probably don't need the B mode so much.

Gear differences 2012 D, C, B

Posted: Wed, 24 Dec 2014, 01:15
by LauraiMiEV
Definitely the brake triggers regen. I'm suddenly very happy I have a 2012.

Haven't driven for a couple days so still waiting on my pedal to the metal test...

Gear differences 2012 D, C, B

Posted: Sat, 10 Jan 2015, 01:29
by Peter C in Canberra
Agreed with all that. The B/D/C positions in the 2012 are only for controlling how much regen you get with the pedal off, no change to gearing or drive level. Regardless, you get max region from the first bit of brake pedal travel. I tend to use D for reasonably easily controlled coasting and too lazy to go to other positions. My wife prefers C because she worries about slowing down without the brake light coming on.

Gear differences 2012 D, C, B

Posted: Sun, 11 Jan 2015, 14:01
by LauraiMiEV
I can't tell a diff in acceleration between B/D/C on my 2012 iMiEV. I personally prefer driving in B and minimising the use of my brakes (and maximising battery regen).

I get the worry about no brake light. Last week some guy had to slam on his brakes behind me as my regen kicked in when the speed limit dropped from 80 to 60 and I just lifted off the accelerator. If he hadn't been tailgating me he'd have been fine but he was so I watched him closely in my mirror. Honestly B isn't a lot different then using lower gears to brake your car with a manual transmission in an ICE vehicle so it shouldn't be a problem.

Gear differences 2012 D, C, B

Posted: Sun, 11 Jan 2015, 15:26
by g4qber
on BMW n Teslas brake lights come on automatically.
one foot driving possible
but I still prefer the i-MiEV for its ability to glide and I prefer to use B mode and hands to slow down like manually down shifting in an ICE, feels more like a race car driver before corners.

yep stupid recalcitrant (I love using this Paul Keating word) tailgaters should be forced to get a volt, i3 or outlander PHEV aspire with their collision mitigation / warning systems.

that will learn them.
probably cost them that much when they continually rear end people.

Gear differences 2012 D, C, B

Posted: Mon, 12 Jan 2015, 01:26
by mikedufty
I tend to drive the iMiEV in B mode, the braking doesn't seem much different to engine braking in my manual subaru ICE, which also doesn't trigger brake lights, so I don't think it is so much out of the ordinary as to be a significant traffic hazard.