L vs. D

[sparktakus]

Hi Everyone,

My commute is around 35 miles round trip, freeways and inner streets. I wanted to test the L mode and the D mode to see if there really is a significant difference and kWh "savings" in the L or econo mode. So far I've noticed that driving in D actually gets me more miles per charge than L. I expected the other way around.

For my experiment I drove the same path to and from work, kept radio and air on exactly the same, and tried to keep regular acceleration/deceleration patterns. No jack rabbit starts or bouts of pedal to the floor type stuff. I was too lazy to record exact measurements on the trip meter thingie. Just drove the car for a week in L, and then a week in D. I noticed that the week driven in D, I had to charge the car less! In the L week, I had to plug in everyday whereas the week in D, I remember having a day or two where I did not need to plug in at all. On those days I remember arriving home having like 50 or more miles so I got lazy and did not plug in. The week spent in L, I remember having to plug in everyday.

Anyone have any experience they can share?

 

[markcmann]

I had originally started driving in 'L' mode when I first got the Spark EV as I drive pretty much drive the same way for the same commute every day and haven't noticed a huge significance difference between the two modes. I do see quite a bit of mileage range improvement when there's heavy traffic (stop and go) and regardless of the mode, I think it is just simply brake regeneration that makes the biggest difference? However, I confirmed that regardless of the speed (above 30 MPH) the brake lights do not come on when I lift my foot from the accelerator and do not touch the break while in 'L' mode, which is a big concern as I don't want to get rear-ended.

Based on suggestions from other posts on this forum I've been using the 'D' mode for the majority of driving and have only been using the 'L' mode when there's heavy traffic, which makes it a little easier to slow down without having to stomp on the brakes.

 

[sparktakus]

Thanks for the input. I do enjoy not having to touch the breaks while in L mode, but am also worried about the break lights not coming on. It's definitely a safety concern. I've seen posts here where folks claim that the lights do come on? Someone said if you look in the rear view mirror, you will see the pink glow from the middle break light come on when you take foot off the accelerator pedal. I haven't had the chance to have a buddy drive behind me to confirm.

 

[markcmann]

I drove down a hill recently outside a residential area in the evening which was pretty dark and well above 30 MPH I can confirm the brake lights did not come on when my foot was off the accelerator while in 'L' mode. Truly a safety concern...

 

[LeadFoot]

When driving home after leasing our Spark EV, my wife was following me in bad Silicon Valley traffic. I had paired my phone and while I was talking to her, I asked her if the brake lights were coming on while I was driving in L mode. She confirmed there were no brake lights illuminating while the car was in regen mode...

I'll have to test like sparktakus and see what impact there is to my range between L and D.

 

[markcmann]

The lack of brake lights while driving in 'L' when removing your foot from the accelerator is a major safety concern. According to the owner's manual this is the expected results:

"L (Low): This position reduces vehicle speed without using the brakes. The brake lights will come on when the vehicle is in L (Low) and the accelerator pedal is not being pressed to indicate the vehicle is slowing down."

I think I'm going to call the OnStar Advisor and report this flaw.

 

[markcmann]

I drove down a hill recently outside a residential area in the evening which was pretty dark and well above 30 MPH I can confirm the brake lights did not come on when my foot was off the accelerator while in 'L' mode. Truly a safety concern...

I did some more "testing" in the evening when it was dark and had mixed results. While driving in 'L' mode, the brake lights did indeed come on when abruptly removing my foot from the accelerator but not every time? Speed did not seem to factor into this "test" as each attempt was over 30 MPH. It seems as though if accelerating and then lifting you foot would cause the brakes lights to come on but if lightly accelerating (cruising speed) then lifting my foot the brake lights sometimes would come on but not always? Still a safety concern nonetheless. :?

 

[Electricbowtie]

The Volts for years have not had the brake lights come on when decelerating in L and even though people have mentioned close calls, no one has reported getting rear ended that I can find on the forums. I always watch my rest view to make sure the person is paying attention though.

 

[SenorChispa]

My brake lights do seem to come on fairly reliably when I suddenly take my foot off the gas in L at city speeds. However the light also goes out by itself at a certain point as I approach a stop even if I keep my foot off the gas. I think it must be computer controlled based on rate of deceleration or something. Maybe if you're headed down a steep hill and have a lot of momentum you won't decelerate rapidly enough to trigger the light?

 

[SanDiego]

This was discussed in another post. We've tested it. Seems certain that there is a "de=celerometer" involved, so that the brake lights come on when decelerative force is above a certain level, but not if you're decelerating more gradually. Seems to be engineered intelligently and work properly on our car.

 

[lalacurf121]

headed down a steep hill and have a lot of momentum you won't decelerate rapidly enough to trigger the light?


royal1688

 

[Taxman]

Is the regenerative brake light triggered by brake force (regen kW divided by speed), or by actual deceleration (change in wheel speed)? If you know when the light is on, you could test by seeing if the light goes out sooner on a downhill.

 

[MrDRMorgan]

Is the regenerative brake light triggered by brake force (regen kW divided by speed), or by actual deceleration (change in wheel speed)? If you know when the light is on, you could test by seeing if the light goes out sooner on a downhill.

I drive in L 100% of the time so I had the software updated on my 2014 and 2015 Spark EVs to turn on the brake lights when I take my foot off of the accelerator. From what I can see at night, you must take your foot almost completely off of the accelerator to have the brake lights come on. It has been working great - much better than the 1.5 second delay the cars came with.

 

[Taxman]

So, with the current software, fully lifting with the selector in L gets you brake lights, uphill, downhill, flat ground?

Asking the car to regen brake without using the brake pedal puts on the lights to warn those behind you that you are slowing, not coasting?

That sounds good to me.

 

[MrDRMorgan]

So, with the current software, fully lifting with the selector in L gets you brake lights, uphill, downhill, flat ground?

Asking the car to regen brake without using the brake pedal puts on the lights to warn those behind you that you are slowing, not coasting?

That sounds good to me.

That is exactly how it is working for me. My original concern was that the 1.5 second delay could catch a driver behind me off guard if I was driving in L and took my foot off of the accelerator pedal for max regen. At 50 - 60 mph you can cover quite a distance in 1.5 seconds before the brake lights actually go on. Now, after the software upgrade, the lights come on when I fully back off of the accelerator. I can coast or slow down more slowly without the brake lights coming on. I have watched drivers behind me and I do not see any of them panicking because they did not see my brake lights come on and suddenly found I had started slowing down.

You will need to visit your dealer to have the software upgraded. Your dealer can find this fix in Recall / Campaign 15582 Unwanted Brake Lamp Activation.

If you take your car in, if applicable to your vehicle, have the dealer also perform recall campaign 16007 - Frontal Airbag and Pretensioner Non Deploy. This is a recent safety issue.

 

[Oberon]

You will need to visit your dealer to have the software upgraded. Your dealer can find this fix in Recall / Campaign 15582 Unwanted Brake Lamp Activation.

If you take your car in, if applicable to your vehicle, have the dealer also perform recall campaign 16007 - Frontal Airbag and Pretensioner Non Deploy. This is a recent safety issue.

How do you find out about these updates? I have two Spark Evs, a 2014 that comes off lease in November, so I don't care much, and a 2016 that I purchased in June, so I'd like to keep on top of this one. Thanks.

 

[Taxman]

Campaign 15582 Unwanted Brake Lamp Activation.

So, you let them do a campaign to solve unwanted brake lamp activation, and it makes the brake lights come on sooner?

Whoever titled that one missed his true calling, naming legislation.

 

[MrDRMorgan]

You will need to visit your dealer to have the software upgraded. Your dealer can find this fix in Recall / Campaign 15582 Unwanted Brake Lamp Activation.

If you take your car in, if applicable to your vehicle, have the dealer also perform recall campaign 16007 - Frontal Airbag and Pretensioner Non Deploy. This is a recent safety issue.

How do you find out about these updates? I have two Spark Evs, a 2014 that comes off lease in November, so I don't care much, and a 2016 that I purchased in June, so I'd like to keep on top of this one. Thanks.

I found out about the brake light and frontal airbag recalls from postings on this forum. I suggest you sign up on MyChevrolet.com. There is a NOTIFICATIONS box in the upper right-side of the screen that will show you any recalls for your vehicle(s) once you provide the VIN numbers.

 

[MrDRMorgan]

Campaign 15582 Unwanted Brake Lamp Activation.

So, you let them do a campaign to solve unwanted brake lamp activation, and it makes the brake lights come on sooner?

Whoever titled that one missed his true calling, naming legislation.

I guess having the brake lights come on 1.5 seconds AFTER you let off of the accelerator is considered UNWANTED BRAKE LAMP ACTIVATION. Regardless, the correction works.

 

[Homer]

You will need to visit your dealer to have the software upgraded. Your dealer can find this fix in Recall / Campaign 15582 Unwanted Brake Lamp Activation.

If you take your car in, if applicable to your vehicle, have the dealer also perform recall campaign 16007 - Frontal Airbag and Pretensioner Non Deploy. This is a recent safety issue.

How do you find out about these updates? I have two Spark Evs, a 2014 that comes off lease in November, so I don't care much, and a 2016 that I purchased in June, so I'd like to keep on top of this one. Thanks.

The airbag one just came out-- I found out through the diagnostics page that onstar sends you (there's a link to check the status of recalls)