Kia Niro Forum banner
1 - 20 of 20 Posts

·
Registered
2020 HEV EX Premium (White / Lt. Gray)
Joined
·
85 Posts
Discussion Starter · #1 ·
I've reviewed several older discussions regarding my questions below and perhaps there's more consensus now after more experience with the HEV (and possibly PHEV and EV) which have similar systems. I've begun using the regenerative paddles more on my EX Premium HEV to see if I enjoy using them or find I'm getting better range, etc. I generally have only used the paddles to increase regenerative braking while driving down steeper mountain grades where they're nice to use as a sort of "engine brake". I still think that's probably the best case for using that feature as it can be a bit frustrating around the city (especially level 3 which creates for a choppy deceleration unless you're very careful with the accelerator pedal). So, here are my questions as well as some additional thoughts:

1. Has anyone established (as fact) at what point the brake lights engage when using the paddles to increase regeneration? I don't think they come on at lower levels but perhaps they do at level 3. I can't see the reflection of the brake lights behind me very well but based on the reaction of drivers behind me, they are not seeing brake lights at least at some levels and I think I'm setting myself up to be rear-ended one of these days if I continue to use the feature around the city. At Level 2 and 3 the car really slows quickly and foot pedal braking is only required below a few MPH. Based on previous discussions it's my understanding I'm not getting any more regeneration using the paddles as compared to using the brake pedal which provides an infinite range of regeneration. And the second I tap the brake pedal I can be sure the brake lights are coming on so I'm beginning to think it's the safer driving option especially for urban environments.

2. Related to this topic is regenerative braking while using adaptive cruise control. As I'm sure many of you have experienced, the shortest safe-distance setting still allows for cut-offs from more aggressive drivers that suddenly change lanes in front of you and then the Niro responds suddenly with regen braking. I would hope the brake lights come on in this situation, but again, do we have a definitive answer with regards to this?

I could see a system coming (and perhaps it's basically already here with single pedal driving and certainly with self-driving technologies) where you push a regen/braking button ONE time and the car brings itself to a stop gradually just 5 feet behind the car in front of you at a stop light. Obviously in such a scenario the brake lights would illuminate. I'm just not sure they are illuminating smartly with the current technology in the Niro.

Thanks for your input!
 

·
Registered
2022 Niro Touring SE
Joined
·
53 Posts
I don't think the brake lights come on at all when you use the paddles, just the brake pedal.
 

·
Administrator
2022 Bolt EUV Premier
Joined
·
2,484 Posts
My Niro didn't have a paddle to increase regen, so I can't compare with those thoughts. My Bolt has a paddle, and I do agree that using the paddle isn't as smooth as simply pressing the brake pedal to increase regen.

Best I can recall with mine, the brake lights come up based on the deceleration rate. When my battery was fully charged, such as pulling out of my garage, there's no space for regen to go, so the car offered little to no regen. The HEV can't be charged when parked, so that wouldn't be an issue there. I believe the brake lights came on without too much regen. I can say that my Bolt will turn on the brake lights with almost no regen. Anything above coasting deceleration will turn them on. In One Pedal Driving mode, my brake lights come on at the slightest level of regen, and they stay on after I stop until I press the accelerator to start moving.

So far, One Pedal Driving still requires the driver to modulate the level of regen/braking to come to a smooth stop at the proper distance. For a car to brake as you envision will require a level of automation that has not yet been achieved. That would require the level of automation that a completely autonomous vehicle would have, and we aren't close to that yet, regardless of what Tesla claims their cars can do.
 
  • Like
Reactions: doro6529

·
Registered
Joined
·
3,537 Posts
Going down hills and holding speed is lots easier to do with cruise control on. I don't see the value of paddles to control regen other than perhaps selecting a true coast.

Medium regen braking does light up the brake lights as have been reported in numerous posts on here and the Ioniq forum. Some have actually managed to make an indicator light reflecting when the brake lights light on the dash. Others mount a mirror or something light colored behind the center brake light to see the point where they light up. Taping something to your rear window and driving at night would be an easy way to settle your mind on the subject. Of course using the brake pedal no matter how light will always turn on the brake light.

Most cars on American roads are automatic equipped and require brake activation for perhaps most slowing operations. Thus most drivers do not bother to notice moderate deceleration provided by manual transmission vehicles and are tuned in only to brake lights. As such, if you choose to always use the brake pedal to slow moderately, that is the safest in our driving environment. Personal choice.

For me, I spend 95% of my driving in cruise control, both for ease of driving with my thumb leaving my leg relaxed as well as best efficiency and typically slow either by turning CC off, or down, neither of which usually activate the brake light. But whether I'm slowing or not, I am checking my mirrors frequently as an active driver looking for anything dangerous happening behind me.
 

·
Registered
2020 HEV EX Premium (White / Lt. Gray)
Joined
·
85 Posts
Discussion Starter · #6 ·
Thanks for the feedback! It would be a nice standard feature to have a light on the dash to indicate when the brake lights are illuminated. I'll consider taping something reflective near the center light to see if that verifies my assumptions and matches what some others have said about lights coming on at level 2 and 3. I use the cruise control mostly on open roads but sometimes on city roads when there's not too much traffic. I'm tempted to override it often when I see hills coming. When going down hill (where I see an uphill stretch just ahead of it) it's tempting to push down the accelerator to increase the momentum and prevent the car from slowing with regeneration while I gain a few MPH as I start climbing up the next incline when I know the ICE will kick in and/or rev up. That's probably not increasing my overall efficiency but it's just leftover behavior from older cars without adaptive cruise control and regeneration capabilities. I'll bet if I let the SCC do what it wants on hills it would likely be a wash. Somewhere I've read that when using onboard navigation the system may compensate in similar ways as it knows the elevation gains/losses along a route. But I haven't paid enough attention to know whether that's the case with my nav or not.
 

·
Registered
Joined
·
73 Posts
I never verified but someone else indicated they chaecked and indicated break lights came on on level 2 and 3 using pedals.
I recently asked about this after noticing when going over a small mountain pass at night sometimes I could see the "cyclops" brake light in my mirror with 4-5 bars of regeneration on the gage and other times no light with 6 bars. Someone (likely Dan) mentioned the light activation is based on deceleration and that may be correct. On a steeper downhill, one can have lots of regen but little deceleration because of the slope. (I.e. just holding speed.)
 

·
Registered
Joined
·
3,537 Posts
When going down hill (where I see an uphill stretch just ahead of it) it's tempting to push down the accelerator to increase the momentum and prevent the car from slowing with regeneration while I gain a few MPH as I start climbing up the next incline when I know the ICE will kick in and/or rev up. That's probably not increasing my overall efficiency
Actually that is a hypermiler technique called driving with load. With practice, that can increase mpg in limited scenarios. In real life, setting your cruise control will improve mpg for 99% of drivers over such techniques. Personally, it really annoys me when drivers slow up hills and speed down hills, I think what idiots! Can they not set their CC and make everyone behind them improve their efficiency and mood? Especially annoying on a two lane hilly road, just as you have the field of vision for a safe pass, they speed up!

If you ever drove a 30 HP Bug fast, that hypermile technique was needed to keep your speed up. Also with 3CVs and similar low powered European cars. One also had to lag far behind traffic in front and time your passes starting your acceleration early 10 seconds or more. Not required with any current car on the market.
 

·
Registered
2020 HEV EX Premium (White / Lt. Gray)
Joined
·
85 Posts
Discussion Starter · #9 ·
If you ever drove a 30 HP Bug fast, that hypermile technique was needed to keep your speed up. Also with 3CVs and similar low powered European cars. One also had to lag far behind traffic in front and time your passes starting your acceleration early 10 seconds or more. Not required with any current car on the market.
My first cars were Hondas in the 80s and this was required for them as well, especially on mountain roads. In fact I'm not sure any of my cars could sustain some of the inclines (loaded) here in the CO Rockies until I bought my 2010 VW Diesel Golf which was very fun to drive in the hills. I sold it 3 months before the diesel emissions scandal hit. If I had kept it I would have been able to drive it one more year without depreciation and turned it back in to VW for the value when the scam was revealed and pocketed an additional $5K compensation. Oh well. That actually would have been a pretty stressful situation so things probably worked out for the best.
 

·
Registered
Joined
·
5 Posts
I can say with certainty that the brake lights come on at regen level 3. After I saw someone else say it happened, I checked it out at night when I could reliably see my brake lights. However, the brake lights went back off when I slowed to about 10 MPH. I assume it has something to do with rate of deceleration as others have mentioned.
 

·
Registered
Joined
·
73 Posts
If you ever drove a 30 HP Bug fast, that hypermile technique was needed to keep your speed up.
In 1971, I had a new VW squareback (small station wagon) on a trip around Lake Superior. On the northern side, the Trans Canada hwy. was then a 2-lane road with many short hills and curves. I cursed the slow-moving "garbage trucks" (rec. vehicles) that were difficult to pass. I tried to anticipate passing opportunities by dropping back slightly and then accelerating to a slightly higher speed and peeking past the big vehicle hoping for clear road ahead. If so, continue accelerating. If not, hit the brakes & drop behind while cursing.
 

·
Registered
Joined
·
3,537 Posts
In 1971, I had a new VW squareback (small station wagon) on a trip around Lake Superior. On the northern side, the Trans Canada hwy. was then a 2-lane road with many short hills and curves. I cursed the slow-moving "garbage trucks" (rec. vehicles) that were difficult to pass. I tried to anticipate passing opportunities by dropping back slightly and then accelerating to a slightly higher speed and peeking past the big vehicle hoping for clear road ahead. If so, continue accelerating. If not, hit the brakes & drop behind while cursing.
Yup, been there. However I usually started from farther back and had perhaps a 20 mph overtaking speed at decision point. If negative, I'd have to drop back and rewind the car like a Slinky toy.
 

·
Registered
2020 HEV EX Premium (White / Lt. Gray)
Joined
·
85 Posts
Discussion Starter · #13 ·
After a recent road trip to Phoenix I was wondering under which situations "Regenerative Conditions Are Not Met" (or similar statement which appeared on my dash as I tried to increase regeneration with the paddles). I know some of them such as when the battery is full and when cruise control is on. But what else would lead to conditions not being met? I noticed that it would not allow me to increase regeneration even though the battery was about 90% full so there may be a cut-off level where added regen is not permitted. And one more question. If the HEV battery is full and can't be charged any more, does that ever necessitate the engine remaining on all the time? I seemed to notice that on a number of occasions but I can't quite pinpoint under what conditions this happened. I just remember it didn't seem to make much sense to me at the time such as when I was decelerating or some such thing.
 

·
Registered
Joined
·
5 Posts
I have accidentally hit the paddle to start regen when the cruise was still engaged and saw that message. I did also see it when the battery was full coming down out of the mountains. Those are the only times I have seen it.
 

·
Registered
Joined
·
73 Posts
I noticed that it would not allow me to increase regeneration even though the battery was about 90% full so there may be a cut-off level where added regen is not permitted. And one more question. If the HEV battery is full and can't be charged any more, does that ever necessitate the engine remaining on all the time?
I often see "battery full" if I try regen. right after I leave home with SOC @ 99-100% but after about 98 or 97% that msg. goes away and regen. works. You mention HEV battery. Do you actually mean PHEV?

Also, when I coast or use the brake petal the Power meter shows regeneration even when battery is full. I presume the car allows a little regeneration via coasting or moderate brake use if the battery is not absolutely full. But if you have a conventional hybrid then your car is different from mine.

I've not yet ascended or descended a long hill like I-17 N of Phoenix. But when I do, I plan to start the hill with room in the battery for regeneration. (Maybe 70% SOC.)

Fred
 

·
Registered
Joined
·
3,537 Posts
If the HEV battery is full and can't be charged any more, does that ever necessitate the engine remaining on all the time?
No, the motor will use battery power to fully drive or add torque to the wheels. But in the case of a regeneration attempt like going down a hill or simply braking, the engine will turn on to use compression braking in addition to the physical brakes.
 

·
Registered
Niro HEV, 2020, Dynamic Link, KIA Connect, EPB, StdGen5W
Joined
·
176 Posts
I have this situation sometimes, when it is cold on short distances. The ICE is only running as long the motor is too cold. On the dashboard graphic I can see then, that my car is driven by the e-motor and the running ICE is loading the battery. If the motor is warm enough (may be a little bit more than 50 degree celsius), the ICE stops and I can make a long trip only with e-drive, max. 4.5 km, before the ICE is starting again ...
 

·
Registered
2020 HEV EX Premium (White / Lt. Gray)
Joined
·
85 Posts
Discussion Starter · #18 ·
No, the motor will use battery power to fully drive or add torque to the wheels. But in the case of a regeneration attempt like going down a hill or simply braking, the engine will turn on to use compression braking in addition to the physical brakes.
I think this must have been what I was noticing. I was likely braking while going downhill with a full battery and noticed that the engine was on. So much to think about but it's all very interesting!
 

·
Registered
2020 HEV EX Premium (White / Lt. Gray)
Joined
·
85 Posts
Discussion Starter · #19 ·
I often see "battery full" if I try regen. right after I leave home with SOC @ 99-100% but after about 98 or 97% that msg. goes away and regen. works. You mention HEV battery. Do you actually mean PHEV?

Also, when I coast or use the brake petal the Power meter shows regeneration even when battery is full. I presume the car allows a little regeneration via coasting or moderate brake use if the battery is not absolutely full. But if you have a conventional hybrid then your car is different from mine.

I've not yet ascended or descended a long hill like I-17 N of Phoenix. But when I do, I plan to start the hill with room in the battery for regeneration. (Maybe 70% SOC.)

Fred
Although we've chatted via PM, I just wanted to clarify that I have an HEV (I just changed my profile to show that below my name) but I'm sure some of the same principles apply. It's interesting that with a PHEV it would make sense to plan ahead by allowing some room in the battery for regeneration on long descents like you mentioned on I-17 and like we have on I-70 west of Denver. I'd be interested to know what percent regeneration you get on a PHEV battery on that downhill drive (or EV for that matter).
 

·
Registered
Joined
·
73 Posts
I'd be interested to know what percent regeneration you get on a PHEV battery on that downhill drive (or EV for that matter).
According to
.
Regenerative braking allows the range of the EV to be extended; however, the efficiency of capturing this energy is reported to vary from 16% to 70% (Boretti, 2013). The reason for this significant difference in efficiency will depend on the driver's style of driving whether they brake gradually or severely. Furthermore, temperature of the system and outside ambient temperature affect the efficiency greatly.

also:
An experimental set of data published by a US laboratory in 2001 on the efficiency of motors or likewise generators is displayed in Fig. 2.6.1 relevant to engines or generators that are rated 75–100 hp. or 56–75 kW. Fig. 2.6.1 illustrates that when the motor or generator is subjected to a load factor above 0.2, efficiency is in excess of 97%. Loads below this show a significantly fall in the motor/generator efficiency. Applying these findings to the vehicle shows that when the vehicle is driven at low speed or in other terms is operated with low loading the motor efficiency is low.
Rectangle Slope Font Parallel Pattern
 
1 - 20 of 20 Posts
Top