EV cars brake fluid
Discussion
Pica-Pica said:
TwinKam said:
Evanivitch said:
TwinKam said:
Because it has been deliberately evolved to take in water. Yes, you read that right.
You do not want little puddles of water sitting in all the low points in the lines, developing internal rust spots. You want any moisture to be 100% homogenised (absorbed) into the brake fluid so that, as others have said, it will all be removed along with the fluid when it is flushed. Inasmuch, brake fluid should be considered a 'consumable'; it deteriorates by design during its useful life of two to three years because it changes from being pure brake fluid into a fluid that contains moisture and rubber seal debris etc.
With my brake fluid tester, which is in daily use, I can clearly see from its 'traffic lights' the water content/contamination rising progressively from 0% in Y0 when the fluid was changed, through Y1, Y2, and generally is maxed out (showing a red light) by Y3. No difference on Hybrids or EVs.
If this is entirely true that it is fully homogenised, why ever do a full fluid change? Why not partial reservoir changes annually or more often?You do not want little puddles of water sitting in all the low points in the lines, developing internal rust spots. You want any moisture to be 100% homogenised (absorbed) into the brake fluid so that, as others have said, it will all be removed along with the fluid when it is flushed. Inasmuch, brake fluid should be considered a 'consumable'; it deteriorates by design during its useful life of two to three years because it changes from being pure brake fluid into a fluid that contains moisture and rubber seal debris etc.
With my brake fluid tester, which is in daily use, I can clearly see from its 'traffic lights' the water content/contamination rising progressively from 0% in Y0 when the fluid was changed, through Y1, Y2, and generally is maxed out (showing a red light) by Y3. No difference on Hybrids or EVs.
Do yourself a favour and do a full change, starting by sucking as much as you can from the reservoir, refilling with fresh, then bleeding say 100 to 150ml from each corner in turn into a see-through container. Hold it up to the light each time. Now go round again and look at the four samples again. You'll be pleased that litre is out.
NB. Use a look-up to ensure that you use the correct type fluid, most modern cars use a lower viscosity type because of ESP, I've found few people that are aware of this.
The dangers of skim-reading... 
100 to 150ml (direct from the reservoir) + 4x (100 to 150ml) (first pull) + 4 x (100 to 150ml) (2nd pull)
Evanivitch said:
So when you're using your brake fluid tester, where are you taking the sample from? All four corners? I thought it was typically just done at the reservoir.
I'm just talking daily drivers, I wouldn't suggest cutting corners on performance or track vehicles.
Yes, the reservoir, it's an almost irrelevant test... it's not testing what's actually in the system, but in my experience it is indicative of how long the fluid has been in the system, hence it's handy for checking on a car where the brake fluid history is unknown (unless someone has 'cheated' by merely renewing that in the reservoir). If the reservoir fluid is contaminated, then you'd hardly want any of it to progress into the system, hence the need to desire it at that time.I'm just talking daily drivers, I wouldn't suggest cutting corners on performance or track vehicles.
I really don't understand the resistance to changing brake fluid every 2 to 3 years, it's hardly a big expense, probably no more than £60 to £80 at most places, especially compared to the cost of a new ABS assembly, which is what is at risk.
Although proposed many moons ago, brake fluid testing never become part of the MoT because
a) there was the concern that a failure would become an easy pass merely by changing the reservoir fluid
and b) the risk of the examiner dropping the cap down the back of the engine (part of the reason that they are not allowed to remove anything during the test).
thebraketester said:
stevieturbo said:
hidetheelephants said:
Have you ever driven an EV? Unless driven like it's stolen very little brake use, mostly when coming to a halt. Another nonsense thread filled with EV FUD.Let's face it, many modern cars have huge brakes compared to cars of yesteryear
EVs need more braking capacity because they are heavier than an equivalent ICE car, however, a very big part of the braking is provided by the regenerative system, so, their brakes do not get used much except in emergency-like situations. Normal road driving requires minimal use of the actual brakes, especially if you are reading the road ahead correctly.
Edited by MustangGT on Tuesday 19th March 07:44
I don't have nor will have an EV (very likely to be a hybrid next) but am asking a genuine question here.
I know battery and hybrid cars are fitted with regenerative braking and that's a good thing, but is it possible to turn off regen braking on them? not as anyone with an ounce of sense would do unless perhaps on icy roads.
I ask because as a lorry driver i know a sad minority of alleged lorry drivers actually switch off the retard functions on the vehicles they drive because they say they don't like the sometimes mildly violent auto downshifts as the vehicle slows down...many drivers reduce the power of auxiiiary retardation on slippery surfaces especially when empty for obvious reasons but i'm speaking of the contingent who turn it all off permanently and drive on the brakes everywhere.
Of course the sensible EV driver will do as one poster above mentions and give the brakes a good work out every now and again to clean things up, but are there any EV drivers who switch regen off, if so why?...this is a genuine question.
I know battery and hybrid cars are fitted with regenerative braking and that's a good thing, but is it possible to turn off regen braking on them? not as anyone with an ounce of sense would do unless perhaps on icy roads.
I ask because as a lorry driver i know a sad minority of alleged lorry drivers actually switch off the retard functions on the vehicles they drive because they say they don't like the sometimes mildly violent auto downshifts as the vehicle slows down...many drivers reduce the power of auxiiiary retardation on slippery surfaces especially when empty for obvious reasons but i'm speaking of the contingent who turn it all off permanently and drive on the brakes everywhere.
Of course the sensible EV driver will do as one poster above mentions and give the brakes a good work out every now and again to clean things up, but are there any EV drivers who switch regen off, if so why?...this is a genuine question.
I think you can select different levels of re-gen
Don't know how much is automated thereafter, like if you did choose a silly heavy setting which then led to problems with ice driving which could well be possible.
https://www.youtube.com/watch?v=BwZSRvVBwFE
https://www.youtube.com/watch?v=dG5hMdsyHUU
Don't know how much is automated thereafter, like if you did choose a silly heavy setting which then led to problems with ice driving which could well be possible.
https://www.youtube.com/watch?v=BwZSRvVBwFE
https://www.youtube.com/watch?v=dG5hMdsyHUU
Smint said:
but are there any EV drivers who switch regen off, if so why?...this is a genuine question.
I don't know anyone that does or can switch regen off. Some cars disable regen if the battery is 100% state of charge. Some car allow you to use the buffer.Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Evanivitch said:
I don't know anyone that does or can switch regen off. Some cars disable regen if the battery is 100% state of charge. Some car allow you to use the buffer.
Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
One hopes the system takes into account the effect of a switched off regen when it takes over if its slippery, one could imagine on a RWD EV that the extra retardation when auto regen cuts in could easily cause a rear wheel lock up.Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Just looked the comments in particular to the videos posted by Stevieturbo above re Teslas in the snow, some commenters under the impression regen can't be turned off (enough?) that the vehicles can become really quite unwieldy in such circumstances.
Some of this must be put down to inexperience or not bothering to learn their vehicle (or failure to RTFM), we do after all see enough half witted driving in all sorts of vehicles, retarding by methods other than braking (who even changes down gears any more) is a whole new concept to most people who have never driven a truck or bus.
Smint said:
One hopes the system takes into account the effect of a switched off regen when it takes over if its slippery, one could imagine on a RWD EV that the extra retardation when auto regen cuts in could easily cause a rear wheel lock up.
I think it's a non issue in a modern vehicle. Certainly not something I've seen reported on ID3.Smint said:
I know battery and hybrid cars are fitted with regenerative braking and that's a good thing, but is it possible to turn off regen braking on them? not as anyone with an ounce of sense would do unless perhaps on icy roads.
I know the Honda Jazz hybrid has a ‘B’ position just rear of ‘D’ which gives regenerative braking, so presumably ‘D’ doesn’t on its own. Also the Jazz Advance Sport has paddles whereby you can modify the amount of regenerative deceleration.Evanivitch said:
I don't know anyone that does or can switch regen off. Some cars disable regen if the battery is 100% state of charge. Some car allow you to use the buffer.
Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Errr............ if the battery has 100% charge then how has the car got to a speed where regen braking would be possible? Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Biggy Stardust said:
Evanivitch said:
I don't know anyone that does or can switch regen off. Some cars disable regen if the battery is 100% state of charge. Some car allow you to use the buffer.
Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Errr............ if the battery has 100% charge then how has the car got to a speed where regen braking would be possible? Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Evanivitch said:
Biggy Stardust said:
Evanivitch said:
I don't know anyone that does or can switch regen off. Some cars disable regen if the battery is 100% state of charge. Some car allow you to use the buffer.
Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Errr............ if the battery has 100% charge then how has the car got to a speed where regen braking would be possible? Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Mr E said:
My leaf needed brake pads at ~50k miles because they had rotted through lack of use.
I tend to try to do a “big” stop one or twice a week these days.
I just replaced disks and pads on an EQC at 20k miles through lack of use. (rust)I tend to try to do a “big” stop one or twice a week these days.
Rather painful when less than 2 years old.
EVs need ceramic brakes.
E-bmw said:
Evanivitch said:
Biggy Stardust said:
Evanivitch said:
I don't know anyone that does or can switch regen off. Some cars disable regen if the battery is 100% state of charge. Some car allow you to use the buffer.
Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Errr............ if the battery has 100% charge then how has the car got to a speed where regen braking would be possible? Some people turn off/down the regen when you come off the accelerator. But the car will still use regen when you apply the brake pedal.
Evanivitch said:
Some car allow you to use the buffer.
.
.
Gassing Station | Suspension, Brakes & Tyres | Top of Page | What's New | My Stuff