[nguthrie]

I am training myself to drive with a light foot to maximize my mileage. The one thing I cannot figure out is how hard I can decelerate using regenerative braking before the friction brakes kick in and turn my hard earned kinetic energy into heat. Is there any indication anywhere which shows when the friction brakes are engaged? If anyone from Kia is listening I think this would be a good addition to the display which shows the energy flow from / to the engine, battery, and wheels. Maybe something that highlights the wheels when the brakes are hit hard.

 

[yticolev]

I'd like a better indication of just that myself. But for now, watch the charge indicator on your far left when braking. When it gets to the area with more green, deceleration is notably increased but I believe still no friction brakes.

All cars get better gas mileage if you slow far before you need to stop or come to a lower speed limit. That applies to hybrids even more so. But to my mind, one benefit of a hybrid is you can drive more normally without annoying traffic behind you by braking later as you will recover some energy unlike a non-hybrid. But slowing even earlier is better if no one is behind you. More energy recovered and less momentum lost (you may not need to brake at all in many circumstances).

Hybrids are notorious for having funky brake feel due to a poor transition from regeneration to brakes. I saw a few complaints from reviewers of the Ioniq/Niro last year, but most lauded the seamless braking. I cannot feel the transition either. That is actually a good thing from a driver's perspective, but it would be nice to have a screen widget for when the hydraulic brakes are activated.

 

[yticolev]

Above, I wrote green area instead of blue charging area. Where the blue line gets wider is the sweet spot for maximum braking.

Reading on PriusChat, Prii have better widgets than the Niro for knowing when the physical brakes are activated (besides the funky feel). With increasing experience in my Niro, it is clear to me that if you never exceed moderate braking, the disc brakes are never engaged until you have reached a complete stop to hold the car. Strictly hard braking, 99% of which can be avoided. Brakes on hybrids usually go 75,000 miles or more before service.

 

[fernando]

I have no idea, but after 12k miles the dealer told me my brakes have 90% life left.

 

[KK6PD]

I really don't worry about it. I try to plan stops a tad earlier than I did before my Hybrid/EV life! I let the throttle up, lightly hit the brake pedal as I get closer, apply more and more as needed. The ultimate goal is to still be in motion as the car in front of me starts to accelerate in front of me. It takes more energy to start from a dead stop than to use momentum to resume speed! Hypermilers Tip #11

 

[padonion]

Hello,
this question is very interesting.
I'm always trying to stay in the "blue" regenerative part of the monitor while braking (if nothing gets in front of me of course ), and I assume that disc-break activates only if I saturate this regen monitor. But it is based on a feeling and nothing technical. It would be great to have confirmation from Kia (technical engineer) that disc get not engaged until you saturate regen, or having a visual information somewhere on the display.

That information is even more useful going downhill in mountain condition. For example, going down from Sequoia Park (30 minutes trip downhill pretty steep), is it safe to gently press the brake pedal all the way down, not saturating the blue regen monitor? Or should I worry about brake temperature and use manual shift for engine brake??

Christophe.

 

[91cavgt]

My daily commute includes driving VERY early in the morning when there is not any traffic. I found that if you apply the brakes lightly till the indicator is barely pointing at the G in the word Charge, the brake lights are not on. This to me says that is the limit to regen braking without activating the friction brakes.

 

[yticolev]

It is the demand for slowing that will activate the mechanical brakes if the regen braking is not sufficient. Nothing to do directly with the regeneration rate. A panic stop at high speeds will immediately demand friction brakes - but at the same time (if you could look at the dash in such a situation), the regen will be maxed out - which of course aids in maximum braking.

 

[Nouseformonkeys]

I have nothing else to add, but I do notice when pulling into my driveway or into a parking spot, that the car will stop before I want it to even when I let off the brake. Once it has stopped, the car won’t inch forward until I step on the gas pedal again.

And I also will let off the gas when I see that I have to stop up ahead so that I don’t have to use the brakes prematurely and maybe won’t have to stop completely before traffic starts moving again.

 

[padonion]

It is the demand for slowing that will activate the mechanical brakes if the regen braking is not sufficient. Nothing to do directly with the regeneration rate. A panic stop at high speeds will immediately demand friction brakes - but at the same time (if you could look at the dash in such a situation), the regen will be maxed out - which of course aids in maximum braking.

I think we all agree on this point, the system manages by itself the need of mechanical brake to slow down at our requested pace.
But the question is if there could be any indication that we reach this limit where regen brake is not enough anymore and then the system requires mechanical brake.

As I said, during downhill for a long period, how do I know that my brake pressure on the pedal relays only regen brake or requires mechanical brake?

Christophe.

 

[yticolev]

I have nothing else to add, but I do notice when pulling into my driveway or into a parking spot, that the car will stop before I want it to even when I let off the brake. Once it has stopped, the car won’t inch forward until I step on the gas pedal again.

And I also will let off the gas when I see that I have to stop up ahead so that I don’t have to use the brakes prematurely and maybe won’t have to stop completely before traffic starts moving again.

Something wrong here with the car's behavior in that first paragraph. Second paragraph is hypermiling - good job!

As I said, during downhill for a long period, how do I know that my brake pressure on the pedal relays only regen brake or requires mechanical brake?

Christophe.

Regen is sufficient to maintain speed down the steepest hill. Better practice is to use cruise control to maintain speed rather than the brake pedal though.

 

[padonion]

Something wrong here with the car's behavior in that first paragraph. Second paragraph is hypermiling - good job!

Regen is sufficient to maintain speed down the steepest hill. Better practice is to use cruise control to maintain speed rather than the brake pedal though.

I agree on highways and freeways, but it sounds not safe to be on Cruise control during windy mountain road downhill where you need to negotiate some U-turns

 

[yticolev]

Regen is strong! Unless you need to negotiate turns at less than 20 mph, cruise control works great. Otherwise, you can control your speed below 20 mph with the brake pedal using regen. When safe to resume, coast to 20 and resume cruise control. I did just that with perhaps a 20% grade and a 35 mph speed limit over five miles of a one way road. Some of the curves were pretty exciting at 20 mph, but the car handled fine.

 

[deltasmith]

Hello,
...
That information is even more useful going downhill in mountain condition. For example, going down from Sequoia Park (30 minutes trip downhill pretty steep), is it safe to gently press the brake pedal all the way down, not saturating the blue regen monitor? Or should I worry about brake temperature and use manual shift for engine brake??

Christophe.

I haven't actually tried this with the Niro, but with other cars I've driven, a crude technique for discovering brake temperature is to pull over, get out of the car, and touch the metal part of the wheels (not the hub caps) to see how warm they are (if you only try this with one wheel, be sure that it's a front wheel since they usually do more of the mechanical braking than the rear wheels do). If you attempt this, you should initially regard the wheels as potentially hot enough to burn your finger: think of how you would test the temperature of a hot iron and maybe moisten your finger and only touch for a fraction of a second at first, until you are certain that the wheel is not burning hot.

When I've done this in the past, the reason for doing it was to discover if I might have one brake that was dragging and heating up more than the others. That's something that's more of a concern once the car gets older though.

In theory, the ideal discovery is that the wheels will feel like ambient temp. In reality though, they might be slightly warmer than ambient, because the rubber tires might also add some heat to the wheel (tires tend to heat up when you are driving by a small amount). If the wheel feels hotter than the rubber tire, then it's likely that you've recently been using your mechanical brakes in addition to your regen brakes, and the surplus heat you feel is an indication of energy lost to heat, rather than being recaptured by regen. If the wheel really does feel burning hot, then in addition to not recovering energy via regen, you might also be overheating your mechanical brakes, which is something that is easy to do on a long mountain downgrade in a conventional car if you rely on just the brake and not the regen or engine braking.

 

[padonion]

I haven't actually tried this with the Niro, but with other cars I've driven, a crude technique for discovering brake temperature is to pull over, get out of the car, and touch the metal part of the wheels (not the hub caps) to see how warm they are (if you only try this with one wheel, be sure that it's a front wheel since they usually do more of the mechanical braking than the rear wheels do). If you attempt this, you should initially regard the wheels as potentially hot enough to burn your finger: think of how you would test the temperature of a hot iron and maybe moisten your finger and only touch for a fraction of a second at first, until you are certain that the wheel is not burning hot.

When I've done this in the past, the reason for doing it was to discover if I might have one brake that was dragging and heating up more than the others. That's something that's more of a concern once the car gets older though.

In theory, the ideal discovery is that the wheels will feel like ambient temp. In reality though, they might be slightly warmer than ambient, because the rubber tires might also add some heat to the wheel (tires tend to heat up when you are driving by a small amount). If the wheel feels hotter than the rubber tire, then it's likely that you've recently been using your mechanical brakes in addition to your regen brakes, and the surplus heat you feel is an indication of energy lost to heat, rather than being recaptured by regen. If the wheel really does feel burning hot, then in addition to not recovering energy via regen, you might also be overheating your mechanical brakes, which is something that is easy to do on a long mountain downgrade in a conventional car if you rely on just the brake and not the regen or engine braking.

Thank you for the advice deltasmith. That will be my next experiment I will let you know how it goes!
(But this is why I said that a dashboard indicator would be welcome! )

Christophe.

 

[yticolev]

Here is a youtube video of just such a heat test on an Ioniq forum (same exact drivetrain as a Niro).
https://www.ioniqforum.com/forum/7-hyundai-ioniq-general-discussion/31296-geezer-gearhead-test-finding-out-just-how-effective-regenerative-braking.html

 

[Bearing1]

I find it interesting that we must ask when friction brakes are being used. It speaks well for Kia to have such a seamless transference from regen to friction brakes that it is not detectable.
Actually in my car 2018 (Touring) I can't tell when it go from ICE to Hybrid mode either except for looking at real time gas mileage.
Go Kia.

 

[jmurphEV]

I find it interesting that we must ask when friction brakes are being used. It speaks well for Kia to have such a seamless transference from regen to friction brakes that it is not detectable.
Actually in my car 2018 (Touring) I can't tell when it go from ICE to Hybrid mode either except for looking at real time gas mileage.
Go Kia.

If I'm paying attention I can feel a very slight vibration in the gas pedal when the ICE kicks on but that's about it. That's the benefit of the hybrid-starter-generator vs a conventional geared starter. Being belt driven the HSG is super smooth and quiet. Compared to a rental Audi I had in Italy that had the engine start/stop feature with a conventional starter. That was obnoxious especially at stop lights.