Regeneration reduced by last software update

[george]

Hi, my PHEV 2014 had last service a month ago.
Immedialtely after that event I noticed that the regeneration is clearly reduced (say nearly half) both using the brake pedal and the paddles.
Is that normal?
Many thanks

 

[elm70]

Hi, my PHEV 2014 had last service a month ago.
Immedialtely after that event I noticed that the regeneration is clearly reduced (say nearly half) both using the brake pedal and the paddles.
Is that normal?
Many thanks

Strange

I would expect regeneration is less due to cold weather .. if battery are cold, they can't get a burst of charge

Anyhow .. my B5 normally goes up to 1/3 or of the regeneration max level shown on the dash

I'm quite sure my service that I just did, they did not update any firmware. As well .. no difference notice between before and after

 

[anko]

Biggest impact is SOC. When the battery is nearly full, regeneration is near 0. SOC needs to down below approx. 65% (50% on the gauge) before max regen capacity is available.

 

[elm70]

Biggest impact is SOC. When the battery is nearly full, regeneration is near 0. SOC needs to down below approx. 65% (50% on the gauge) before max regen capacity is available.

Definitely ... but this should have been notice also before the service.

Anyhow .. B5 does normally go up to 33% ... does this match with you ? .. and yes .. I can feel the brake is less in B5 when battery is full .. then it does progressive increase

 

[anko]

Anyhow .. B5 does normally go up to 33% ... does this match with you ? ..

Without braking? Roughly yes. With braking it is more. I would say up to 70%.

 

[elm70]

Anyhow .. B5 does normally go up to 33% ... does this match with you ? ..

Without braking? Roughly yes. With braking it is more. I would say up to 70%.

Ok thanks

Yes, B5 without braking ... when the foot is on brake then I would guess B0 or B5 doesn't matter any more, it is all about the car speed and how strong is the push the brake pedal .. and if I recall right , I have seen close to 100%

 

[anko]

Anyhow .. B5 does normally go up to 33% ... does this match with you ? ..

Without braking? Roughly yes. With braking it is more. I would say up to 70%.

Ok thanks

Yes, B5 without braking ... when the foot is on brake then I would guess B0 or B5 doesn't matter any more, it is all about the car speed and how strong is the push the brake pedal .. and if I recall right , I have seen close to 100%

In my experience, B0 + max brake gives less regen than B5 + max brake. Indeed not what one would expect, but I got this from monitoring amps and voltage on the drive battery. The reason for this could be that a lower B-setting could be less harmful to the battery. It could explain why I am on 31.3 Ah battery health :mrgreen:

Anyway, this is why I always advocate to use B5 when trying to achieve max battery range.

 

[elm70]

In my experience, B0 + max brake gives less regen than B5 + max brake. Indeed not what one would expect, but I got this from monitoring amps and voltage on the drive battery. The reason for this could be that a lower B-setting could be less harmful to the battery. It could explain why I am on 31.3 Ah battery health :mrgreen:

Anyway, this is why I always advocate to use B5 when trying to achieve max battery range.

Very interesting .. I would have not expect this ...

About your 31.3Ah ,,, how many KW does report your last charge over the MMCS ?

 

[anko]

7.8 - 8 seems common. But this is reported by my kWh meter, not MMCS.

 

[george]

The regeneration is now working properly as before.
It seems that the tuning of the system is auto adaptive. Probably a reset was performed by the service personnel.

 

[elm70]

The regeneration is now working properly as before.
It seems that the tuning of the system is auto adaptive. Probably a reset was performed by the service personnel.

Interesting

I'm wondering which type of auto adaptive should be done and for which reason in the "regen"

Somewhere I have read that B5 implies like X m/sec2 deceleration , this is not consistent with what the kw regen gauge report when I'm using it B5

I see that regen power is higher at higher speed ... I have seen it even going above the recharge scale (over 60kw?), after a constant B5 regen from 130kmh down to 60kmh

I would expect B1 to B5 is mapped to a fix regen power ... since the regen power is tight to the constant deceleration (on a flat road) ... fix deceleration will make no sense when going downhill, which is possible the main motivation of the B1 to B5 selection ... be able to keep constant speed while going downhill and on the same time recharge the battery

 

[anko]

Somewhere I have read that B5 implies like X m/sec2 deceleration , this is not consistent with what the kw regen gauge report when I'm using it B5

I see that regen power is higher at higher speed ... I have seen it even going above the recharge scale (over 60kw?), after a constant B5 regen from 130kmh down to 60kmh

Amount of poiwer needed to achieve a fixed deceleration depends on speed. At 150 km/h you need much more power to actively slow down, then you do at 50 km/h. (something with force * distance traveled per second)

I would expect B1 to B5 is mapped to a fix regen power ... since the regen power is tight to the constant deceleration (on a flat road) ... fix deceleration will make no sense when going downhill, which is possible the main motivation of the B1 to B5 selection ... be able to keep constant speed while going downhill and on the same time recharge the battery

B5 means 1 m/s2 deceleration.
On a 10% slope, gravity roughly results in 1 m/s2 acceleration.

Combined result is constant speed

What I did not write was: the "targeted 1 m/s2 deceleration in B5" was taking into account speed, but not added weight of luggage, trailer, gradient, wind, etc.

 

[elm70]

Somewhere I have read that B5 implies like X m/sec2 deceleration , this is not consistent with what the kw regen gauge report when I'm using it B5

I see that regen power is higher at higher speed ... I have seen it even going above the recharge scale (over 60kw?), after a constant B5 regen from 130kmh down to 60kmh

Amount of poiwer needed to achieve a fixed deceleration depends on speed. At 150 km/h you need much more power to actively slow down, then you do at 50 km/h. (something with force * distance traveled per second)

I would expect B1 to B5 is mapped to a fix regen power ... since the regen power is tight to the constant deceleration (on a flat road) ... fix deceleration will make no sense when going downhill, which is possible the main motivation of the B1 to B5 selection ... be able to keep constant speed while going downhill and on the same time recharge the battery

B5 means 1 m/s2 deceleration.
On a 10% slope, gravity roughly results in 1 m/s2 acceleration.

Combined result is constant speed

What I did not write was: the "targeted 1 m/s2 deceleration in B5" was taking into account speed, but not added weight of luggage, trailer, gradient, wind, etc.

I don't know if my memory of physics at school are fading away .. or ...

My memory tell me .. power = mass * acceleration
So ... deceleration at 1 m/sec2 ... is a fix power , only variable is the amount of mass.
Different story is if we go downhill, since the potential energy is different ... so .. slow down the car of 10km/h into 1 second, we have the energy from reduced "motion" energy + reduced "potential energy" (potential energy is < mass * high * gravity >.. "motion energy" is < mass * speed * speed >

Also ... descending at constant speed it imply no deceleration (no delta in motion energy, only delta in potential energy) .. so if the car is programmed to sense the deceleration and force it via regen brake .. it simply won't work on downhill

PS: On the gauge .. I think that it is shown an "average" value .. I guess .. this could justify why it does not does immediately to X kw of regen power associated to the Bx .. but it does increase while keeping Bx engaged ... I have seen a off scale value of regen ... when battery was almost fully empty (per the dash, that means around 25% SOC in reality) ... so possibly regen power is also limited to which voltage are jumping up the lithium cells while "regen" is going on .. and this could be often the upper limit of B5 :?:

 

[jaapv]

I can assure you that it does work downhill...

 

[elm70]

I don't know if my memory of physics at school are fading away .. or ...

My memory tell me .. power = mass * acceleration
So ... deceleration at 1 m/sec2 ... is a fix power , only variable is the amount of mass.
Different story is if we go downhill, since the potential energy is different ... so .. slow down the car of 10km/h into 1 second, we have the energy from reduced "motion" energy + reduced "potential energy" (potential energy is < mass * high * gravity >.. "motion energy" is < mass * speed * speed >

Also ... descending at constant speed it imply no deceleration (no delta in motion energy, only delta in potential energy) .. so if the car is programmed to sense the deceleration and force it via regen brake .. it simply won't work on downhill

PS: On the gauge .. I think that it is shown an "average" value .. I guess .. this could justify why it does not does immediately to X kw of regen power associated to the Bx .. but it does increase while keeping Bx engaged ... I have seen a off scale value of regen ... when battery was almost fully empty (per the dash, that means around 25% SOC in reality) ... so possibly regen power is also limited to which voltage are jumping up the lithium cells while "regen" is going on .. and this could be often the upper limit of B5 :?:

yes ... I have bad memory of physics ..

Mass * Acceleration is not power, but the "strength"

"strength" * distance = energy

power is energy divided by time

So .. yes .. at fix deceleration .. regen power is proportional to the speed

Anyhow ... if the car is going down at constant speed ... there is no acceleration (unless I'm again mistaken in physics) .. so the car can't have an "accelerometer: sensor that dictate the regen power :shock:

I guess ... there must be an algorithm in the car that define the regen power based on the current car speed


Speaking of a "accelerometer" ... this actually has a different reading if the the accelerometer is not anymore horizontal, ... so .. maybe it could work to use an accelerometer in the car (which may need to be calibrated too for provide consistent result)

OK .. enough of physics and maths ... for me B5 or B1 is just a different way to slow down without using the braking pedal and recover energy

 

[anko]

I don't know if my memory of physics at school are fading away .. or ...

My memory tell me .. power = mass * acceleration
So ... deceleration at 1 m/sec2 ... is a fix power , only variable is the amount of mass.

I think mass * acceleration = force, not power. Power = force * speed = mass * acceleration * speed. So, same deceleration at higher speed requires more stopping power (gives more regen power).

Edit - crossing posts :mrgreen:

 

[anko]

Anyhow ... if the car is going down at constant speed ... there is no acceleration (unless I'm again mistaken in physics) .. so the car can't have an "accelerometer: sensor that dictate the regen power :shock:

I guess ... there must be an algorithm in the car that define the regen power based on the current car speed

Indeed, a simple algorithm that takes into account standard mass, rolling resistance, etc. and current speed, but not added mass, wind, gradient, ...... will do.

 

[elm70]

Indeed, a simple algorithm that takes into account standard mass, rolling resistance, etc. and current speed, but not added mass, wind, gradient, ...... will do.

So ... no accelerometer in the car :?: ... like in my DIY drones ... the MPU6050 3 axis gyros and accelerometer cost only 1 USD per chip

Only issue that I can see .. is if the car get a hole on the street or any imperfection .. 6050 instant reading could be "odd" .. but a good "digital filter" can smooth down "the elements"

Back to the original topic ... maybe they have an adaptive PID algorithm for adjust the regen power ... and an accelerometer too .. this could explain why regen power is different after a 'reset"

So ... also what is looking apparently simple ... in practice it can be quite complicate

 

[anko]

So ... no accelerometer in the car :?: ... like in my DIY drones ... the MPU6050 3 axis gyros and accelerometer cost only 1 USD per chip

Another one of your famous bugs? Lets take one step back: why should there be one in the first place? I cannot imagine anybody ever missed one.

 

[ian4x4]

Jerk

In physics, jerk, also known as jolt, surge, or lurch, is the rate of change of acceleration; that is, the derivative of acceleration with respect to time, and as such the second derivative of velocity, or the third derivative of position. Jerk is a vector, and there is no generally used term to describe its scalar magnitude (more precisely, its norm, e.g. "speed" as the norm of the velocity vector). According to the result of dimensional analysis of jerk, [length/time3], the SI units are m/s3 (or m·s−3); jerk can also be expressed in standard gravity per second (g/s).
https://en.wikipedia.org/wiki/Jerk_(physics)

To get to the bottom of this you will probably need to look at the extreme case of the PHEV dropping vertically, and then work things through, from the rate of change of position= Velocity; rate of change of velocity= Acceleration; and then rate of change of acceleration= Jerk( not sure if this is the appropriate name).

Force=mass*acceleration and gravity supplies the force downhill.

Any object requires a force applied to change its velocity.

Best of luck with working out how much gets to the battery.