Possible future brake problems with Hybrids/EV's

[Orionaut]

Somebody I know has recently purchased a PHEV.

Now he hasn't actually had it that long and it already has some 8000 miles on it, so it gets plenty of use.

However, despite this, the disks are already showing signs of quite noticeable surface pitting and corrosion.

To my mind, they simply are not getting enough actual use to keep them clean since the car uses regenerative braking most of the time and only uses the disks/pads when braking hard.

The problem here, and I have seen this many times over the years on cars that only get light use, sooner or later he is going to get those bands of heavy corrosion creeping in from the edges of the sweaped surface until the disks and pads are going to need to be replaced not because of wear but simply because of unacceptable levels of corrosion.

Now, in this case, the vehicle in question is an Audi Q8. A new set of disks/pads all round is probabally going to cost as much as a small car!

But even on less expensive models I am wondering whether this is going to become a routine issue in the future on EV's and hybrids that are designed to use regenerative braking for anything other than emergency stops.

It would be a bit daft if the fuel savings made on one side of the balance were eaten up by higher servicing costs on the other...! :/

 

[Jonnycoupe]

He needs to brake a bit harder every so often. Plugins and BEV limit regen when full anyway as the battery can’t absorb it so likely to be less of an issue.

 

[paradigm]

I’d have thought that the manufacturers would have implemented something similar to the tech used to dry brakes in heavy rain, by actuating the calliper to lightly apply the brakes for a short period. This would be enough to keep surface rust at bay.

 

[Matthew.M]

Do they charge it at home to 100%?

With my i3 when the battery is full regen braking is significantly reduced (there’s nowhere for the energy to go if the battery is fully charged). In this state the car uses the friction brakes to simulate regen to keep the driving experience consistent. In practice this means the discs are scrubbed every morning.

 

[Nasher]

Maybe drive a bit with the brake pedal pressed slightly so they at least get some use and clean off any surface rust. Otherwise they might find when they properly need to stamp on the brakes, the stopping distance is much longer than it should be!

 

[d_brennen]

I imagine their extra weight would counter being used less often/less aggressively to some extent

 

[Simon]

I had an i3 once whilst mine in for service and the brakes were shockingly bad

 

[OspreyO]

....
It would be a bit daft if the fuel savings made on one side of the balance were eaten up by higher servicing costs on the other...! :/

Luckily thus far all EV have far lower servicing costs. Its one of the advantages of a EV.

A regular Q8 must eat brakes and discs considering the weight of it.

 

[[TW]Fox]

Luckily thus far all EV have far lower servicing costs

All? I take it you've not seen the servicing prices at Tesla?

 

[bimbleuk]

It will always affect a percentage of cars regardless of the propulsion from I've seen. Some people just drive less, use brakes less generally and don't have any mechanical knowledge as it's simply a means of conveyance to them. I've always had to keep an eye on my dads cars as he drives low miles and generally slowly on local roads. I've had to trigger particulate purges on diesels and go out and clean the discs of rust with some heavy braking.

Yes EVs will probably suffer this more but as mentioned I always do 1 or 2 manual brakes each time I drive in my i3 to clear the discs especially as I often cycle to work so my car can stand for several days. 37000 miles on my EV and the brakes clean though the pads are certainly close to being replaced for the first time.

 

[robj20]

Do they look similar to this, these are my rear discs. Not a Hybrid, but its very common on my car, no one can narrow down exactly why it happens, but replacing the pads and discs with aftermarket ones and it doesn't happen. Also happens on a few different makes of car.

 

[jpaul]

However, despite this, the disks are already showing signs of quite noticeable surface pitting and corrosion.

some of this pobably depends on driving environment ... country roads around here, which some use a lot, with mud/tractor detritus, salt too,
otherwise I use brakes sparingly and have run discs out to 130k+ miles without pitting.

.... are there any statistics showing ev energy recovery efficiency
... since, as commented in other thread, you really need supercapacitors to store the large amount of energy ... which is only captured on driven wheels ?

 

[Journey]

Now, in this case, the vehicle in question is an Audi Q8. A new set of disks/pads all round is probabally going to cost as much as a small car!

Except that if the problem is as bad as you suggest then the product is faulty since that model of vehicle has been out less than one year, it would be covered by Audi as not for for purpose, unless it had done 100K+ miles. If this 'somebody' you know hasn't approached Audi about the issue, then they are frankly an idiot.

 

[bainbridge]

Maybe going back to drum brakes would be a solution.

 

[OspreyO]

All? I take it you've not seen the servicing prices at Tesla?

No idea How does it compare with a car of similar performance and equipment levels.

 

[Nasher]

Luckily thus far all EV have far lower servicing costs. Its one of the advantages of a EV.

Teslas cost more than most ICE cars to service for some reason. Parts are also very expensive and can be hard to get hold of. Most indi garages won't touch EVs for anything more than changing the tyres etc, so you'll also be paying dealer prices.

 

[OspreyO]

.... I always do 1 or 2 manual brakes each time I drive in my i3 to clear the discs especially as I often cycle to work so my car can stand for several days. ...

Same here. Our ICE cars do very little mileage. So would have to do something similar to clear brakes. We also had to upgrade the battery as it wasn't getting charged enough on so little driving.

 

[OspreyO]

Teslas cost more than most ICE cars to service for some reason.

I dunno if someone asked about servicing costs of a golf would some one compare it to the servicing cost of AMG Merc.

Are we saying the service costs of a Tesla are more than that of Q8?

 

[Matthew.M]

Teslas cost more than most ICE cars to service for some reason. Parts are also very expensive and can be hard to get hold of. Most indi garages won't touch EVs for anything more than changing the tyres etc, so you'll also be paying dealer prices.

Servicing a Tesla is optional. They’ll still honour the warranty if you decide not to bother. Ever. I don’t know a single ICE car with the same warranty conditions.

Owners only really have to service them if they have the car on finance as the conditions of the agreement usually require It.

 

[OspreyO]

EV's have been around for a long time now. Most of the concerns about them have not been realised.