Recuperation issue?

[daveb3473]

Odd one. Driving my 4 CT yesterday (6000 miles on it) the power meter did not show recuperation in the grey ring of the power meter. Usually there is a grey ring for power and one for recuperation.
When starting off usually, the first 5 or so brakes are on the physical brakes and then recuperation takes over. This time the grey bar which indicates the amount of recuperation available started at about 5 degrees and gradually expanded to the full amount over about 20 miles of city driving. It was not constant either. It would be 20 degrees then drop to 10. Then back to 20 etc.
Worried there is an underlying issue?

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[WuffvonTrips]

How close to full battery charge were you?

 

[W1NGE]

Odd one. Driving my 4 CT yesterday (6000 miles on it) the power meter did not show recuperation in the grey ring of the power meter. Usually there is a grey ring for power and one for recuperation.
When starting off usually, the first 5 or so brakes are on the physical brakes and then recuperation takes over. This time the grey bar which indicates the amount of recuperation available started at about 5 degrees and gradually expanded to the full amount over about 20 miles of city driving. It was not constant either. It would be 20 degrees then drop to 10. Then back to 20 etc.
Worried there is an underlying issue?

Depending on conditions (weather, temp etc), braking recup should be available within a mile or so and indicated with the green bar.

What happens when you enable overrun recuperation - press the button on the steering wheel?

 

[daveb3473]

How close to full battery charge were you?

I was on 100% charge at the time, which is unusual as usually charge to 85%

 

[daveb3473]

Depending on conditions (weather, temp etc), braking recup should be available within a mile or so and indicated with the green bar.

What happens when you enable overrun recuperation - press the button on the steering wheel?

Yes - activated auto recuperation and made no change

 

[WuffvonTrips]

I was on 100% charge at the time, which is unusual as usually charge to 85%

That might explain your issue then- the car can only recuperate if there's unused capacity in the batteries to absorb the recuperated energy.

 

[daveb3473]

That might explain your issue then- the car can only recuperate if there's unused capacity in the batteries to absorb the recuperated energy.

Thanks - makes perfect sense - I should have figured!

 

[kort]

I was on 100% charge at the time, which is unusual as usually charge to 85%

if you are at 100% SOC there can be no recuperation, where would the the kw go?

 

[WuffvonTrips]

Thanks - makes perfect sense - I should have figured!

It's surprised me on occasion (like yourself I rarely fully charge). It does mention the scenario in the handbook somewhere, but I'd have thought that the battery capacity being significantly larger than its usable capacity would have avoided this recuperation "feature".

 

[allroadusa]

Page 27

 

[kurand]

This problem of what to do with excess energy is much more interesting on cars with one pedal driving. Certainly needed to be aware if SOC was 100% when starting a journey in my i3.

 

[Jhenson29]

But, unless starting at the top of a hill, the car should have already expended more energy than it will recuperate, even if starting at 100%. So, there should be “room”.

Is it more of a recup power limit at 100% or capacity calculation limitation at 100% (I.e. it can’t tell it has room)?

 

[WuffvonTrips]

But, unless starting at the top of a hill, the car should have already expended more energy than it will recuperate, even if starting at 100%. So, there should be “room”.

Is it more of a recup power limit at 100% or capacity calculation limitation at 100% (I.e. it can’t tell it has room)?

Might it be allowing for a worse-case scenario of prolonged downhill braking, to avoid the risk of starting to brake with max recup then losing that capability while still in the same braking event?

 

[Jhenson29]

Might it be allowing for a worse-case scenario of prolonged downhill braking, to avoid the risk of starting to brake with max recup then losing that capability while still in the same braking event?

You’d think it could calculate that and transition to friction brakes as needed.

 

[W1NGE]

Yes - activated auto recuperation and made no change

Ok so as you've had 100% soc then any recup will be limited until the battery starts to discharge.

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