Brake problem?

[Arizona Willie]

I've been complaining about hearing my brakes when driving very very slowly out of my driveway and serveral times I have seen a popup warning that regenerative braking was limited even though it seemed to be working ok.

This morning it came on and stayed on for along long time and finally went off.

I think I might have a problem.

 

[stickman]

regen is limited when you're at vey high states of charge, and when the batteries are cold. Don't know if you knew that.

 

[Arizona Willie]

regen is limited when you're at vey high states of charge, and when the batteries are cold. Don't know if you knew that.

No I didn't know that. But the temp was about 68 degrees and I had driven the car several miles to a dental appointment and then after I left it started with that popup warning. It was at 90% charge when I started this morning.

 

[AlanSubie4Life]

At 90% state of charge or thereabouts you will have substantially limited regen. Especially when cool. But even when not that cold.

I do get the impression that all packs are not exactly the same (comparing to others I know locally), but hard to tell because there are so many variables (SoC, cold soak, charge timing, ambient temp, garaged, insolation (sun) ).

If you charge at home, delay your charging so that it completes closer to departure time - if this is possible - it depends how consistent your driving habits and charging habits are; not an option for everyone.

 

[Arizona Willie]

At 90% state of charge or thereabouts you will have substantially limited regen. Especially when cool. But even when not that cold.

I do get the impression that all packs are not exactly the same (comparing to others I know locally), but hard to tell because there are so many variables (SoC, cold soak, charge timing, ambient temp, garaged, insolation (sun) ).

If you charge at home, delay your charging so that it completes closer to departure time - if this is possible - it depends how consistent your driving habits and charging habits are; not an option for everyone.

I don't understand why they throw up a warning though. Makes me think something is wrong.

 

[AlanSubie4Life]

I don't understand why they throw up a warning though. Makes me think something is wrong.

It warns you because lack of regen substantially changes the driving characteristics of the car. Good to know in advance that you will need to use the brakes...

 

[mswlogo]

You should not see much limit at 90% SOC. I charge to 90% every time.

Arizona can have large temp swings. How cold is it getting at night?

 

[Arizona Willie]

You should not see much limit at 90% SOC. I charge to 90% every time.

Arizona can have large temp swings. How cold is it getting at night?

Getting really really cold. Down in the 50's.

 

[Arizona Willie]

It warns you because lack of regen substantially changes the driving characteristics of the car. Good to know in advance that you will need to use the brakes...

OK. But the thing is my regen seemed to be working normally. Hmmm.

 

[AlanSubie4Life]

OK. But the thing is my regen seemed to be working normally. Hmmm.

Even when you get the message you will have some regen, so on reasonably flat roads with conservative driving it might be sufficient regen to slow you down at the desired rate. For the exact status: Look at the "dots" on the bar immediately underneath the speedometer.

On the left hand side (green), it indicates to you that regen is limited if there are any dots. However, it only complains (pops a message) if there are a LOT of dots. Dots on the "black" (right) side of the bar indicate that power is limited (usually due to low SoC).

This indicator is a real-time indicator of power flow in/out of the battery as well.

I have found that at 90% SoC in San Diego at 50-60 degrees I would have up to half of the bar full of regen dots, and occasionally I will get the regen limited message (it's borderline). It's a lot less severe if I charge to 80%. Unless you need the range (or would be more comfortable with the additional range) I would set your typical charge level to 80%.

If you accelerate briskly a few times you'll see the dots tend to disappear.

 

[mswlogo]

Getting really really cold. Down in the 50's.

That’s probably the main reason and is normal. It is more sensitive to limited regen at higher SOC.

The combination of 50F at night and 90% SOC and observing limited regen is completely normal.

I would think it would not take long to warm up at 68F though and that you are not that limited (20-30%)?

Keep in mind no matter what level of regen you have if you can minimize using brakes you can still do extremely well on efficiency. You just have to anticipate taking your foot off the accelerator just a little sooner the more regen limited you are.

 

[T.Antony]

Regarding the brakes, yes, mine too are loud. They don’t squeak or anything, and they don’t necessarily ride the rotor when not applied, but when I do apply them at low speed, I hear them very prominently sliding against the rotors. It’s as if the pads are just very low quality. It’s not rust in the rotors either. I make sure to ride the brakes for a short distance after a particularly damp morning. I have 15k on the car now, ample time for rotor and pad break in, they’re just... not quiet.

 

[kbecks13]

Regarding the brakes, yes, mine too are loud. They don’t squeak or anything, and they don’t necessarily ride the rotor when not applied, but when I do apply them at low speed, I hear them very prominently sliding against the rotors. It’s as if the pads are just very low quality. It’s not rust in the rotors either. I make sure to ride the brakes for a short distance after a particularly damp morning. I have 15k on the car now, ample time for rotor and pad break in, they’re just... not quiet.

Hmm are you sure it's not a light coating of rust on the rotors and/or something on the pad? I've had slight noises (when i was on OEM pads) after letting the car sit for a while, but it would always go away after some braking. I think mostly it was because we rarely use the brakes!

 

[Vines]

I have heard my stock brakes in the morning, and the solution is usually to give them like 6-10 good stops each week right in a row.
As an EV, you probably barely use the brakes, so this is normal.
Some people put it in low Regen mode one day a week, that works too.

 

[Magnets!]

Mine don't make any sound that I've noticed but I am careful as Vines suggests above to put regen in low once in awhile and do some hard acceleration and braking while descending a hill (with no other cars around).

 

[Arizona Willie]

Yes I think I am just hearing the pads being applied to the discs at low speed. Creeping out of the driveway.
Don't hear anything at higher speed except for tire noise.