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Comment by wesleyd | Hacker News Reader

> An honest manufacturer would only advertise the amount of capacity you can actually use day to day, rather than the capacity that is there but you really shouldn't use unless you want your battery to die young.

Toyota do this. In fact, all PHEV manufacturers seem to do this: they keep their batteries between 15% and 85% and only advertise this range.

Insofar as they advertise it at all: the battery size in eg a Prius prime is buried in a footnote, and the range - miles/km - is what’s advertised, and is real, and corresponds to the 15-85.

I guess it is more important in a PHEV to never fully charge not discharge their batteries: most cycle from full-ish to empty-ish much more than a BEV. And so it is more logical for them to publish their 15-85. But the honesty is refreshing; BEV numbers feel disingenuous to me.

I ignore all breathlessly excited battery “breakthrough” headlines, but I ignore any from Toyota less!

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As a layperson when it comes to batteries, this whole 15-85% thing seems like a silly detail that should be handled by computers. Like, at 85% the readout should say “100%”, and at 15% it should say “0%”.

Is that something they do, or do they expect users to be aware of these thresholds?

My VW PHEV does this. It doesn't use the HV battery below 20% and the range calculator knows this.

So I can die on the road with enough energy to drive another 50 km?

> So I can die on the road with enough energy to drive another 50 km?

My gas car has a 42 litre tank, if i wait until the light has come on and the gauge is on (and then drive another 20km past that), I can only get 38.5 litres in.

I'll do you one better: mine has a 45 litre tank, light goes on at 5 litres left, gauge stops indicating at half of that, but there's an unmentioned anywhere buffer of 5 litres, which is there so that the fuel pump doesn't overheat or pick up any contaminants at the very bottom the tank.

I only know this because a motoring journalist filmed himself riding the same model dry.

No. The computer in the car will say you can drive 0km but you can actually drive another 50km. How well you can drive that remaining 50km will be a separate question: the battery most likely cannot discharge fast enough for highway driving.

Thanks, that makes sense.

But then Tesla decides to be different, advertises full 0-100% capacity and range, and Musk brags on Twitter how other EV manufacturers can't keep up.

And then builds a level 2 driver assistance system that doesn’t meet any SAE criteria of “self driving”, and brags how other manufacturers can’t keep up.

The Silicon Valley style of “fake it till you make it” business is dishonest.

>The Silicon Valley style of “fake it till you make it” business is dishonest.

And is lapped up by all the mass media contributing to Musk building a brand to rival Mercedes while spending $0 on advertising.

It's quite something, isn't it? You don't have to like it either. Seems that a lot of the USA really does. P.T.Barnum and all that.

Yet to see other auto manufacturers come anywhere near Tesla’s driver assistance system.

> Yet to see other auto manufacturers come anywhere near Tesla’s driver assistance system.

https://www.youtube.com/watch?v=nsb2XBAIWyA

There is nothing more to say about the 'glorious Tesla driver assistance system'. It can't even do basic tasks with super slow speed, no moving objects and all time in the world.

Saying what a Tesla can't do, or do well, doesn't really respond to the parent. There are people using Tesla to drive on city streets in traffic. It'd be fair to say it doesn't always work, and it isn't reliable, but are there other consumer cars that drive themselves through a town?

There aren't any consumer cars that drive themselves through a town. Tesla has a system that assists a human driver through town. This is an important distinction and hand-waving it away is exactly the dishonest and dangerous business practice I was referring to above. Industry academics and practitioners everywhere (including Tesla's rank and file) make the distinction.

https://www.sae.org/blog/sae-j3016-update

Which criteria of the level 3 does FSD fail? I don’t understand since it seems perfectly capable of driving by itself under many, many circumstances, many towns being among those. I just looked at the graphic behind your link, and FSD fulfills all of the requirements, and frankly basic autopilot does as well. Many automakers offer level 3 currently, Tesla of course having been first, but you’re right in saying that none offer level 4.

To me, the distinction between level 4 and level 5 seems abysmally stupid as well - how could you leave out the pedals and steering wheel if the car can’t operate by itself under all conditions, meaning level 4 = level 5. Maybe I just don’t have the IQ to understand what the industry academics and practitioners are conveying here.

Tesla does not offer a level 3 system. When using Tesla FSD, the driver is still responsible for supervising the operation of the system at all times and must intervene when and if the system makes an incorrect input. See the second row in the above-linked graphic.

Also see Tesla's site (buried in the support pages, rather than the marketing copy):

> FSD Beta is an SAE Level 2 driver support feature that can provide steering and braking/acceleration support to the driver under certain operating limitations. With FSD Beta, as with all SAE Level 2 driver support features, the driver is responsible for operation of the vehicle whenever the feature is engaged and must constantly supervise the feature and intervene (e.g., steer, brake or accelerate) as needed to maintain safe operation of the vehicle.

https://www.tesla.com/support/recall-fsd-beta-driving-operat...

> how could you leave out the pedals and steering wheel if the car can’t operate by itself under all conditions, meaning level 4 = level 5.

The graphic gives an example of how this can be offered: local driverless taxi. Waymo's Firefly is an example of this. It had no steering wheel or pedals. It would only operate when, where, and under the conditions where it was capable of doing so.

Depends on the company and product.

Traditional hybrids hide all these details. Most plug in EV’s only show 15-85% as 0-100 because you have a fall back for range extension. Many EV show the close to full range because you might daily drive just fine on 15-85% while charging at home and want to take the occasional long trip or use 0-15% capacity if a charging station is down etc.

Also, charge cycles become less important as range increases an EV with a 220 mile range is noticeably worse at 180 mile range where a 440 mile EV sees 1/2 as many charge cycles and is still perfectly useable with a 360 mile range.

> Is that something they do

Pretty much. There's a catalogue of EVs here:

https://ev-database.org/

Where nominal and usable capacity is stated. Currently even Tesla includes a few kWh of buffer capacity.

State of charge in li-ion batteries isn't a straightforward thing anyway. 4.2V used to be considered 100%, but nowadays some chemistries allow for going up to 4.35V safely - doesn't sound like much, but it translates to ~15% more capacity.

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