(D)rive vs. (B)rake

[cmiller82]

I've owned the car for only 2 days. I have a total of 102km on the odometer. I've also never run the battery down under 75%.

Now that the disclaimer is out of way, I'd like to start a discussion on Drive vs Brake.

I've driven quite a bit in Brake, both in city and the highway. It takes a bit of getting used to, but once you get used to it, you can time it so that you are pressing the brake for the last couple of feet for a stop sign/light. My problem is that most of the time I'd rather coast than regen. If it's a stop sign, you have to stop and then start, so regen makes sense, but if it's a stop light, then just slowing before the light and then timing the green is the best way to go.

The brake pedal used gently charges the battery so why let the car do it on its own?

Is Brake just a lazy setting? or does it actually increase range?

I'll be testing it more in the week. This week I'll be driving between known distances and I'll post my results.

Thanks,
Chris

 

[tractioninc]

I guess that Brake mode is an easy method to let the car harvest regen all the time. When braking via the brake pedal, it's not always easy to keep short of the changeover between regen and actual brake pad application.

I'm used to driving cars with a manual transmission that engine-brake with the lift of the throttle, so B mode in my Soul EV feels most natural for me.

 

[Stewart2673]

Both my wife and I typically use brake mode. Takes some getting used to it. If you feather on and off the accelerator you do not get the quick slow down in Brake mode. I think we are just accustomed to lifting the foot fully off th accelerator and costing before braking in the ICE vehicle. I may be tempted on high way to drive in D mode so I do get a little more coasting. Good to have the choice of either one.

 

[ralyon]

I'm in the same boat as Tractioninc that I used to have a manual, so it was a pretty easy adjustment for me. The harder adjustment was having to keep pressure on the brake constantly to keep from moving. I live in a large city with a lot of traffic, so being able to control the speed more from one pedal without having to switch constantly is enjoyable. You can coast by releasing the accelerator slowly as Stewart has said. Try to glance at the power bar on the left in the dash to see how the pedal actually affects how much power is going in/out while on B mode. Coasting is when you have no bars up or down.

 

[vanillagorilla]

I don't think it helps with range but it's so nice for hilly areas like Seattle.

 

[user 284]

B mode seems to help me quite a bit with range. For instance, I'll start with a range gauge value of, say 107, drive 10 miles on B mode, and the gauge might say 103, when it should say only 97. I think the range gauge drops faster in D.

 

[mysoulev]

I've had my SoulEV for a year now and only tried B mode a few times.

i wonder,
if i'm used to easing up on the accelerator pedal to brake, in a panic situation,
is there a chance that i would by mistake step on the accelerator pedal instead of brake pedal ???

 

[tractioninc]

Personally, no way. I've spent enough time driving on the road, on the the race track, and karting that braking is subconscious muscle memory. Braking is something that happens in *addition* to throttle application, sometimes at the same time (to balance tire traction).

...But I wish I could say that for everyone. Parking lot accidents are reported all the time where people accidentally apply the throttle instead of the brake due to not paying attention. For example - how many times have you seen on the news where someone accidentally drove through a store front? These types of incidents may be happening during street driving as well, but the cause is not so obvious.

 

[mysoulev]

...But I wish I could say that for everyone. Parking lot accidents are reported all the time where people accidentally apply the throttle instead of the brake due to not paying attention. For example - how many times have you seen on the news where someone accidentally drove through a store front? These types of incidents may be happening during street driving as well, but the cause is not so obvious.

my point exactly, i have 30+ years of braking muscle training, but lucky enough, i've only had a handful of panic braking training.
there was a report of a SouEV driving through a storefront but KIA found no fault with the brakes, my suspicion: B mode

 

[slobodanc]

Chris,

There are at least 2 perspectives that result in 2 different answers. So it is important to setup the context.

1) Tech

From the tech perspective, what you describe is 100% correct. As has been said before, the regen process doesn't recapture 100% of energy as there are various inefficiencies. So yes anticipating the traffic ahead to more or less stop the motor completely and just let car coast is the most efficient mode of slowing down.

Even in B more I often try to do this. It is bit harder than in D mode but still possible.
I watch my motor consumption and try to nail it to zero although it may jump to +/-1

2) Other drivers

Like you I used to do this all the time in my older car with manual, switch to neutral and coast. Well 90% of drivers hate me every time I do this. They really can't handle this behavior even when it is clear that traffic light is red ahead.

I was once coasting on a motorcycle having about 500m to red light. A city bus decided that this is not acceptable, accelerated and passed me, then slammed the brakes at the red light!?!

So from this perspective coasting is annoying to others and you don't do it. You use B mode, keep up the speed as expected then let B mode regen slow you down at the light.

Between these 2, my compromise is as follows:
- if alone, try to coast in B mode by managing motor power at zero
- otherwise, in B mode keep up speed and let regen slow me down just before red light or stop sign

I want to avoid annoying other drivers too much as I already drive slower than most so no need to antagonize other drivers even more.

 

[buddhaauthor]

Nice post, slobodanc. Here in Los Angeles drivers do hate coasting despite its efficiency (for both fuel and reducing traffic).

Chris, have you read http://www.mykiasoulev.com/forum/viewtopic.php?f=6&t=284? There's some good detail there on D vs B and ECO.

 

[cmiller82]

Thanks to everyone for their input!

I have just under 900km on the car now and have actually started using Brake mode more. Depending on the drive I will move back and forth between D and B.

My driving never exceeds 100km in a day, so I've also found I've been driving a little aggressively and giggle every time the torque squawks the tires coming out of a tight turn.

I absolutely love this car. I was quite worried about range anxiety and was not completely convinced I could get used to an electric car.

 

[SoulEV2016]

honestly, D is a useless position when i see the ODB2 meter with kW gauge (a real one).

People don't understand that when they keep the pedal accelerator at 25% for example ... the car don't draw electricity at the motor when you drive on downhill road.

Actually, you can even regenerate electricity in the situation (really, install an OBD2 gauge just for this !)

People must loose the habitude of the thermal car ... detach the wheel from the motor is a thing of the pass (specially in the electrical propulsion/traction when you can regenerate the 1st second and draw electricity the 2st second).

Like this (mountain fast drive, ON/OFF pedal profil) : http://imageshack.com/a/img924/2295/MsBgY1.png

 

[buddhaauthor]

Sorry SoulEV2016, but you are going to have to explain things a good deal more for me to understand you. And I really want to! Each of your sentences will have to be a paragraph if you want to communicate useful information to this non-techy brain. (Not stupid, I'm a college teacher; but not technically inclined).

If you have time, I'd love to hear more. Thanks.

 

[SoulEV2016]

Ok, you have a spreedsheet here to view the % of pedal accelerator ...
You see ? Even when i press 13% of accelerator, because i decrease my speed, i don't consume anything (B position).

With D position, you must brake to decrease the speed at the same level.
With B position, you manage the power/regenerative breaking like you want and without touching the brake pedal like in D position.

 

[buddhaauthor]

Thanks SoulEV2016. I understand that B mode allows the car to slow down without engaging the brake per se. In this way, it can regenerate battery power. But the car also regenerates the battery via the brake pedal. So, I think the question is whether the efficiency of one is higher than the other. I believe people were saying that pedal braking is less efficient because it loses energy in friction.

 

[GizmoEV]

But the car also regenerates the battery via the brake pedal. So, I think the question is whether the efficiency of one is higher than the other. I believe people were saying that pedal braking is less efficient because it loses energy in friction.

Try this: With the EV displaying power to/from the motor find a steep hill or open stretch of road to do some slowdown tests. In my case I have a down hill off ramp off a freeway. With the car in D mode drive fast and then slow down fast enough that you need to use the brakes and note the -kW number on the EV display, also note the feel of the deceleration. If you are going down
a hill where you can keep the same braking switch into B mode and letup on the brake pedal to maintain the same deceleration level. You will see that you get more -kW into the battery than in D mode for the same deceleration. This should convince you that B mode is the more efficient one provided that you are not a on-the-throttle, off-the-throttle type of driver.

 

[Ray]

I've had my Kia Soul EV for almost 2 years now. I always drive with the ECO mode on. When city driving, diving up/down hills, or in heavy traffic, B mode is best for me (1 pedal driving, for the most part). When on the freeway, and driving at a consistent cruising speed (60-75 MPH), D mode works well. Then, when taking the off-ramp, I drop it back down to B mode. It's fun to drive this way, and I get about 90 miles per charge, which works for me. My commute is 18 miles each way.

Ray