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by throw0u1t 2708 days ago
I would presume electric drive trains are quite complex.

You'd have independent electric motors on at least 2, perhaps all 4 wheels. You have to redesign entire platforms to fit batteries, ensure the batteries and the drivetrain have adequate cooling, ensure that the electric motors have a certain amount of longevity, and so on.

2 comments

With the exception of a few niche vehicles, most EVs have only 1 (FWD/RWD) or 2 (AWD) motors. Though it's a new platform, electric motors aren't exactly a new technology and overall it's significantly fewer moving parts to fail. There's also the fact that many manufacturers come up with a single "skateboard" platform for multiple vehicles, which reduces the overall complexity of manufacturing EVs.
As far as I understand the current state of EVs, EVs have eliminated the engine and it's ancillaries.

However, EVs still have CV joints, differentials (dependent on the car, Tesla runs an open differential), independent suspension - all of which must be much stronger since electric motors produce far more torque than ICEs and also have the added weight penalty.

The power-train is everything from wheels to engine. Where as drive-train is the power-train minus the engine.

The transmission is the most complicated part of the drive-train and arguably more complicated than all of the other drive-train components combined. In current EVs there is no transmission, just a single reduction gearbox.

In an EV the engine is dramatically simplified compared to an ICE and there are significantly fewer parts and almost no moving parts in comparison.

Another thing to consider is that all internal combustion engines have multiple supplementary systems that are required to function such as cooling, fuel delivery, and ignition. At most an EV motor might require supplementary cooling but no commercial vehicle has one that I'm aware of.

Of course, ICE powertrains have lots of moving parts, but the comparison that EV cars are simple is just not an accurate representation of EV cars.

There are fewer moving parts, I agree. The architecture itself is simpler too, I agree. But the individual components are still massively complex and expensive. High density Lithion-ion is very complex, and also requires a number of supplementary systems to manage power, heat, cooling and monitor the array.

You could make the same argument about the exotic metallurgy used in ICE components. Just like with an ICE subsystem, most of those subsystems you mentioned aren't trade secrets and have far greater operating tolerances than in an ICE.
That's all very old and simple tech. The quality is only limited by the bean counters keeping costs down.
> I would presume electric drive trains are quite complex.

They're significantly less complicated than an ICE power-train and drive-train.

The Nissan Leaf has a single electric motor and a fixed reduction gear box. The only fluids to maintain are the wiper fluid and reduction gear box fluid, which is similar to automatic transmission fluid but requires less maintenance. The battery pack is air cooled and the only servicing is an annual inspection to maintain warranty.

The Tesla vehicles are all direct drive with no gearbox. They come in single or dual motor options. The batteries are cooled and the fluid is changed at 4 year intervals.

The maintenance schedule for an EV is annually changing the cabin filter, wiper blades, and doing a multi-point inspection.

>The Tesla vehicles are all direct drive with no gearbox.

This is wrong. They have a single electric motor (except the dual-motor ones) and a fixed reduction gear box, just like the Leaf. No one does direct-drive electric motors because it's a lot easier to make a faster-spinning motor and then use a reduction gear to get usable torque from it; a direct-drive motor would have to have a huge diameter.

>The maintenance schedule for an EV is annually changing the cabin filter, wiper blades, and doing a multi-point inspection.

You're forgetting the brakes. EVs still have regular hydraulic brake systems that need new pads and fluid, though not as much because they can use regenerative braking much of the time, avoiding use of the friction brakes, which are really for emergency stops and full stops.

> This is wrong.

You're right. I was mistaken, I thought I had read that the Roadster was the only Tesla with a gearbox but that it was eliminated with a free upgrade. There's still a gearbox but it's a fixed single reduction gear.

> You're forgetting the brakes.

I wasn't, I was touching on the differences between an EV and an ICE with regards to maintenance. Brakes are a consumable that are inspected and changed as needed rather than at regular interval like the belts or fluids in an ICE vehicle.

Brakes and brake fluid are part of the multi-point inspection that's done on all vehicles when they're serviced. As you pointed out, EVs use their brakes significantly less than ICE vehicles and so any maintenance of the brake system will be less frequent than an equivalent ICE vehicle.

Overall EVs require significantly less maintenance to their drive/power-train AND to some of their traditional systems (e.g. brakes).

I'd like to refute the point about brakes. A lot of it is based on the driver, not just the vehicle.

I've driven a manual all my life. I don't really enjoy automatics, and I've got to the point now where I've pretty much perfected rev matching and heel and toe so I can engine brake most of the time with minimal wear on my clutch and shock to my drive train.

To be perfectly honest, I don't think I wear my brakes any faster than if I drove an electric car. I'd love to do an experiment to see if this was the case, it sounds like as lot of fun!

However, I concede that most drivers are nowhere near as interested in the technicalities of driving and teaching learner drivers to rev match and heel and toe is probably too complex at that stage in their driving careers.

> However, I concede that most drivers are nowhere near as interested in the technicalities of driving and teaching learner drivers to rev match and heel and toe is probably too complex at that stage in their driving careers.

For every ICE driver like you, there are an equal number of EV drivers trying to optimize their driving habits as well. The difference between ICE and EV when it comes to brake wear is that it's an active effort for an ICE driver and passive for an EV driver.

The regenerative braking in an EV varies by make/model but the 1st gen. Nissan Leaf has by far the least aggressive system. With the Leaf, the brake engagement is based on a number of factors from how fast you're going to how hard you press on the brake. The Leaf will almost come to a complete halt simply by taking your foot off the accelerator and allowing the regen system to drag the car to a stop without ever depressing the brake. In stop-and-go traffic you rarely have to take your foot off the gas.

In the Leaf when you depress the brake pedal the regenerative system ramps up quickly and only after it has peaked do the mechanical brakes engage. When stopping it's not uncommon to hear the mechanical brakes engage just as the car comes to a rest to hold the car at a stand still, it's an audible thunk.

The Tesla Model 3's regenerative braking is quite aggressive compared to the Leaf and if you take your foot completely off the accelerator pedal you will lurch forward in your seat as the car quickly decelerates.

I personally find the Leaf to be a much easier, and a lot less fun, to drive than the Model 3 because of how the brake regen systems work. In my 2015 Leaf I can engage hill mode (aggressive regen) and eco mode (gummy pedal) and then only have to touch the brakes to come to a complete halt. I've yet to find a setting in the Model 3 that compares.

You should go test drive something like the Model 3 as it's a very different driving experience to an ICE in terms of braking.

>You should go test drive something like the Model 3 as it's a very different driving experience to an ICE in terms of braking.

You sound like you took one test drive of the Model 3 at one setting and have no idea that there are multiple settings. If you go through the menus, the aggressiveness of the regen braking is settable. You can make the car "creep" as if it has an automatic transmission, or you can make it not "creep", like cars with manual transmissions and clutches. You can set it for aggressive regen like a real EV, or you can set it for non-aggressive regen so it feels like driving a regular car with an auto trans.

The proper setting, IMO, is the full-EV mode with very aggressive regen. You're not supposed to use the accelerator as an accelerator, you're supposed to use it as a speed control pedal. So you don't take your foot off the pedal at all, unless you need to brake hard. The rest of the time, you keep your foot on the pedal and modulate it to control your speed. If that's a problem for you, it's because you learned bad driving habits with non-EV vehicles, and you need to learn better driving habits now.

I would love to, I'm not sure we will have the Model 3 in the U.K for quite some time still. I'll give it a go when they're available and hopefully report back on a future article!
>Brakes are a consumable that are inspected and changed as needed rather than at regular interval like the belts or fluids in an ICE vehicle.

Wrong again. Brake pads and rotors, yes, but brake fluid needs to be bled and changed at regular intervals regardless of usage.

> Wrong again.

Am I? I said annual maintenance, is brake fluid changed annually? The requirements vary by manufacturer (e.g. Chevy every 45k, Honda every 3 years).

Pedantry aside...

The brake system on an Electric Vehicle will require the same or less maintenance than an equivalent Internal Combustion Engine vehicle.

And Electric Vehicle will require less maintenance overall compared to the equivalent Internal Combustion Engine vehicle.

Yes, you're wrong. Go back and read the line you wrote (I quoted it for you in the previous post). You said brakes are a consumable, and you kinda implied that EV brakes don't even have fluid(!). Now you're admitting that it does need to be changed, which is exactly what I pointed out you were wrong about. This isn't "pedantry", it's a pretty major operation that has to be done regularly (as you said, roughly every 3 years for most cars I think; brake systems are all about the same these days and use the same fluids. My Mazda has a very similar requirement as those you mentioned.) It's not a hard job, but it does take some time and shop labor is expensive so it's not an especially cheap job.

>The brake system on an Electric Vehicle will require the same or less maintenance than an equivalent Internal Combustion Engine vehicle.

This is correct. You don't need to change the pads/rotors nearly as often, but the fluid still needs maintenance.

>And Electric Vehicle will require less maintenance overall compared to the equivalent Internal Combustion Engine vehicle.

Yes, of course, I never said otherwise. But it's important to remember that "less maintenance" doesn't equal "no maintenance". A lot of the systems on an EV are the same as current cars, and maintenance/repair will be little different: wheels/tires/bearings, suspension/ball joints/struts, wipers/washers, brakes, HVAC.

I've seen claims by Tesla that their brakes never need service due to the fact they're barely used. Not sure how accurate that is, but it's sort of logical.
Sounds like BS. Even if you almost never use them, brake fluid has a finite life and needs to be replaced every few years. Brake systems are never perfectly hermetically sealed and brake fluid is hygroscopic.
Plus: What about rust?
Rust is usually rubbed off when the brakes are engaged. Buildup on any vehicle is only really an issue when the vehicle sits undriven for long periods of time.

In EVs the brakes are engaged, just less frequently and with less force. For example in a normal car when you depress the brake pedal gently to slow to a normal stop the brakes engage immediately. In an EV the regenerative braking force increases when you depress the brake pedal and only after it has hit 100% do the brakes engage.

So with an ICE vehicle the brakes are the primary stopping force most of the time where as with an EV they're the secondary stopping force most of the time.