[druhoops]

All – I’ve read through this forum and can’t find any posts on this except here

http://www.infinitiq50.org/forum/20...2-motortrend-q50s-hybrid-test.html#post256418

I’m hoping the expertise of the forum can help. I’ve been driving for 30 years, manuals and not, sport cars and not. So – I know how to brake. But this regenerative hybrid braking system is driving me nuts. I can’t seem to brake smoothly. I’m at 1200 miles on the car and 4 weeks, so I’ve had time to practice. I find that when I apply a fixed level of pressure to the brake, as the car decelerates it suddenly brakes much more strongly with a VERY abrupt deceleration. (Motor Trend reviewer called this the “handoff between regen braking and mechanical breaking” and complained it was abrupt). This happens in all drive modes. I can feel the gears downshifting as I slow down, but the abrupt deceleration is not due to gear downshifts (I know the exact downshift points while in D… 5 to 4 @ 38 mph, 4 to 3 @ 27 mph). It’s as if the system switches from regen braking to mechanical braking, but the mech braking really grabs the brake disks. And all this while at CONSTANT brake pedal pressure. So, I can’t see why a handoff is occurring. I’m not pressing any harder on the pedal. And – I’ve tried braking with the gear selector to the left in manual mode. Still experience varying brake force with constant brake pedal pressure. Advice?

Also, the regen when coasting is way too strong. I can tell by coasting, feeling the drag of the regen, then pushing the gear lever to neutral. You can feel the regen drag really let go… so I have a good sense of how strongly the regen is operating. For any techs out there – is this software controllable/settable by dealership? When I lift off the throttle, the drag is really excessive until the EV mode kicks in and RPMs go to zero. Then, the drag is a bit less. But it is still too strong. Opinions?

Thanks everyone. I still enjoy this car (just hate this one issue).

 

[cvipgo]

I have AWD sports hybrid and I can brake hard and stop on a dime without feeling the transition.

 

[Q50Aggie]

It brakes like normal for me. Not really sure what the abruptness is some people have mentioned

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[Quickfeet32]

I have have the same issue. Went to the dealer today to get the update (1.9), and some splash guards. I asked about the braking because I experience the same thing. The tech said it is controllable via software, and that Infiniti knows it ans are supposedly working up a fix.

 

[gbert15]

I have have the same issue. Went to the dealer today to get the update (1.9), and some splash guards. I asked about the braking because I experience the same thing. The tech said it is controllable via software, and that Infiniti knows it ans are supposedly working up a fix.

That would be nice if that was the case! I think I am on the same boat coming from 6mt as well! Maybe its just more controllable with stick since u choose how u shift as u put on your brakes but its still weird with the Q50 afrer owning it for 3 months already!

 

[InfinitiPlusOne]

Can't brake smoothly, is that from a complete stop or slowly braking?

As for the regen coasting is way too strong, I like it. It give me free regeneration of the hybrid battery. I love it when I accelerate hard to sling shot Q50 hybrid forward fast and let go the accelerator pedal to recharge the battery. That's one way I rake up lots of EV miles

I can’t seem to brake smoothly.

Also, the regen when coasting is way too strong. I can tell by coasting, feeling the drag of the regen,

 

[selzini]

I guess half here are happy and half not. I have no problem with the braking in the hybrid.

And by the way, to the OP, if you make the font any smaller, I'll have to start up the magnifier on my screen. My eyes hurt!

 

[InfinitiPlusOne]

Speaking of brake, anyone know what kind of brake pad they use on the Q50S hybrid?

 

[Klamalama]

You can count me in with those that have a problem with the braking .

I've found that you can smooth it out some by shifting the lever to the manual side while slowing down. Of course it slows down even more, so you use the brake less.

I would prefer that it be reprogrammed.

 

[druhoops]

I have AWD sports hybrid and I can brake hard and stop on a dime without feeling the transition.

Braking hard is not the problem. It's trying to brake gently. The problem comes up in traffic mostly where you try to smoothly keep with traffic flow.

Here's some tech tidbits on our hybrid brakes:

EDIB (Electric Driven Intelligent Brake) | NISSAN | TECHNOLOGICAL DEVELOPMENT ACTIVITIES

Nissan says "Further, it also controls the reactive force from the pedal in order to unify the feeling when stepping down on the pedal and the sense of deceleration." <unified means hybrid + friction brakes>

After many test drives in controlled conditions, I think the problem is all in the regen brake. When you put the car in neutral and brake - smooth as butter. When in combo mode , the initial "bite" the combo brakes is waaay too strong on gentle braking. Needs to be smoothed out. Also - at constant pedal pressure, the brake force surges and sags. When in EV only mode - the braking is not so bad - not sure why. But when the engine is engaged (RPM not zero) and braking - it's a bit of a mess. Again - this is gentle braking, not hard braking. And - I'm pretty sure it's not due to engine downshifting.

I talked to Infiniti service manager and he had no insight about whether infiniti will address this, or if they even consider it a problem. Any recommendations about what to do next? Just live with it? (I'm at 1700 miles).

 

[AustintaciousQ]

Count me as one who is not coming to a stop smoothly in my Q. I am always apologizing to friends riding in my car.

 

[sperry]

Have had the Q50S Hybrid for about 2 weeks, so still learning.

Heavy braking definitely doesn't matter.

However, I too have trouble smoothing out the braking. There is a harsh transition and I would be willing to bet there will be a software update. I have a similar "problem" with spirited driving (finally out of the breakin) but not with the brakes. When I am giving the gas and I am traversing the lanes on a sparsely occupied highway when I let my foot off the gas because I have to slow down a little until a new opening appears the transition from coasting to watching the battery get charged from the car and not the engine is really abrupt even without applying any brake there is a jerk forward even at 70+ MPH.

I get the sense that the computer is trying to hard to use regen under performance conditions. Which in sport mode I don't want. What I really want is in sport mode is to err on the side of optimum power band with the engine and have it augmented by the electric motor. I think that translates to don't do regen under performance driving conditions and have the motor recharge batteries when not discharging the batteries. Because if I am doing 105 MPH and want to heavy brake for a 30 MPH right hander and then get back on the gas after apex I don't want the regen and all that throwing the weight around and disrupting the balance of the car. Which seemed to happened today on an offramp as I tried to manipulate the throttle around an off-ramp and the power from the electric motor was on and off again.

 

[avanti5010]

No braking problem for me. Q50S Hybrid. Where would you be doing 105 mph and braking for a30 mph right hander?? On a public highway?

 

[InfinitiPlusOne]

If we all complain to Infiniti, perhaps they might do something about it.
As for now, I just live with it. I'm already at 5000 miles on my car, I got used to it. The fuel economy and power of the hybrid far out weight the minor annoyance of the not-so smooth braking. Beside, the regenerative braking help charge up the battery. I guess you gain something, you loose something.

. Any recommendations about what to do next? Just live with it? (I'm at 1700 miles).

 

[mrq50]

This is one of the reasons why I opted not to get the Hybrid, Even though I am now second guessing that decision. I want "EV" mode too

 

[sperry]

@Avanti - Turn 1 and Bus Stop at Watkins Glen & turn 1 NHIS

It isn't all the time which makes it kind of hard to determine how to adjust the braking so that it doesn't happen anymore.

I need to do more testing but I did get a lurch at the end of a heavy brake for a quick light on my way home last night. Almost like regen "stops" and increases brake pressure on the calipers to compensate for the change in braking power the regen was giving me.

I did a little more testing and for certain the regen starts as soon as I let my foot off the gas even while driving on the highway or a windy road as indicated by the energy flow diagram in the dash. This is absolutely not what I want! Because that is applying stopping power instead of letting me use my momentum for a bit and I don't want stopping force I just want to coast.

Has anyone else noticed a "slow down" when lifting on the gas while on the highway and not really want that action?

 

[druhoops]

Has anyone else noticed a "slow down" when lifting on the gas while on the highway and not really want that action?

Absolutely - I've noticed it. But there is a bit of both going on here - the regen is slowing you down, but so is the gasser's transmission. You can tell this by lifting off the throttle (selector in D or manual) and coasting from 50 to a stop. You will feel the gears shifting down as well as the regen. 7/6-5 happens at 45 mph, 5-4 at 38, 4-3 at 28 etc. If you are curious what gear you are in, hit the up paddle and you'll see the current gear. It feels a bit like a high compression engine with a manual transmission. You feel strong engine braking when lifting off the throttle. I'd prefer less drag... I hope infiniti is listening...

However - when the planets align, the car switches to all-EV mode when I lift off throttle, and the deceleration is less pronounced.

 

[InfinitiPlusOne]

Don't every car slow down when you lift your foot off the gas pedal?
I took my car for 5k service + software update and my dealer give me a G37 loaner. The G37 slow down is even more pronounce than my Q50S hybrid.
With my Q50S hybrid, I accelerated to 80mph and left go the gas pedal. It can cruise for quite a distance. I always do that so I can get more EV miles. More EV miles = more $$$ to my pocket

 

[andrew]

@Avanti - Turn 1 and Bus Stop at Watkins Glen & turn 1 NHIS

I need to do more testing but I did get a lurch at the end of a heavy brake for a quick light on my way home last night.

This is the one problem I'm having with the hybrid that I find a bit annoying.

I have constant pressure to brake, and lets say I want to let up my braking slightly towards the end of my stop at 5MPH or so, I get that lurch (or I would describe it as a surge).

Anyone have any insight on this?

 

[druhoops]

Don't every car slow down when you lift your foot off the gas pedal?
I took my car for 5k service + software update and my dealer give me a G37 loaner. The G37 slow down is even more pronounce than my Q50S hybrid.
With my Q50S hybrid, I accelerated to 80mph and left go the gas pedal. It can cruise for quite a distance. I always do that so I can get more EV miles. More EV miles = more $$$ to my pocket

Sure - all cars slow down when lifting off throttle - but this one doesn't do it smoothly unless it has switched to EV mode. Abrupt downshifts seem to be the culprit. And yes - when braking, it is nonlinear just before approaching a stop. I'm learning to ease up on the brake right around 10 mph, but it's not how I've been braking for the last 30 years.