Tesla to Buy Energy Storage Firm Maxwell Tech at $4.75 a Share

Because I don’t want to use the pads, I have to drive a bit differently when less regen is available.

I really like single pedal driving in the first place (see note above about lane changes and such) and I would never want to the pads actuating just from lifting the accelerator.

The only enhancement I would be happy with is full regen under all operating conditions :-)

I wouldn't call it nondeterministic, there's a notification window alerting you to the limited reg and there's a "gauge" below the "speedometer" that shows power input/output. That being said, it's bad UX/UI and they could do a better job representing it. The power gauge is a hair thin line with no labels or scale that you must intuit the purpose of by observation.

The Gen1 Leaf isn't really better, it's just different. Theere's again a power gauge that shows power input/output. You can clearly see the scale of the gauge which is better but again you must observe it to understand it's purpose. The Leaf also has rings around each tic in the gauge that denotes if that level is accessible. When the batter approaches 100% charge or it's terribly cold you lose rings on the input side of the gauge and when the battery is exceptionally low you lose them from the output side. Again it's nice if you know what it means but the only way to know is through observation of the gauge.

I'm guessing other EVs aren't any better. We're probably going through a phase much like early automobiles where each manufacturer comes up with novel UIs to complete the feedback loop between car and driver. Eventually they'll all standardize on something universally understood.

But there's definitely a strong correspondence between idiosyncratic experiences, personalities that find such experiences appealing, and personalities that actually buy expensive luxury goods. Most armchair QBs miss that last part.

Someone like you, who would scoff at this weird behaviour, will never buy a Tesla. So why do they care what you think? Some people, the people who actually buy Teslas, talk enthusiastically about the weird behaviours on the Internet, i.e. the most priceless form of viral marketing.

I'm not saying you're right or wrong. That's beside the point. I'm saying you could be right, but you don't really have a solution for, "Idiosyncratic stuff is what payers talk about."

When you're buying a high end vehicle "quirky" is the preferred adjective.

20yo $1500 German cars are "unreliable". Chinese EVs are "buggy". When you buy a Tesla, a new high end Mercedes or some other status symbol it's all just part of how it goes. Unreliability or odd behavior is not a negative at that price point. It's all part of the ownership experience. You don't get to complain about it. It's implied by the price point that you knew what you were getting into and can handle it.

When the battery is full (after descending a long hill) the pre-travel does nothing at all. Of course there's no engine braking during coasting when the battery is full, so you'll know ahead of time.

On newer models, the pedal behaves in the manner you describe.

Well, they actually do regen in Drive with the foot off the pedal; the brake pedal engages traditional brakes (with the regen also). Coasting requires slightly engaging the accelerator.

Prius also has an “engine braking” mode (which actually uses either regen or engine braking, depending on hybrid battery charge state) on the shift lever.

> Prius do regen slightly in coasting mode, but it's not very noticeable

The difference between pedal disengaged regen and pedal engages to coast is quite noticeable.

It also makes way more sense: your drivetrain can't be perfectly efficient so being unable to coast (and regen-braking every time you would be) is a double energy loss, first waste energy converting kinetic to electric, then you waste energy again converting back from electric to kinetic.

Regen-braking instead of coasting only makes sense in an "engine braking" analogue: have the car regen-brake to try and keep below some set speed on downhills.

For comparison, the Model 3 "frunk" seems to be 28" x 15" x 9" = 3780 cu.in. So you'd have to sacrifice the entire frunk for your resistor pack.

Not to mention, it is delusional to consider this style of driving "efficient" because of regeneration. You're paying a premium for acceleration speed, and then being taxed by regneration efficiency...

I’ve never driven a high performance stick shift, only a cheap beater stick as my first car, but I found high RPM stop and go in 1st or 2nd gear was always somewhat hard work and jerky. The TM3 is absolutely not hard work or jerky, the single pedal driving is actually quite a joy IMO.

I was under the misapprehension that they had a much larger energy density. However, my next thought is that not all charging is the same. Only the 1st 60% of a charge is in the constant current part of the charge curve. After that, the charge rate falls off. Charging the last 10% of a battery's capacity takes much longer. What if the supercapacitor bank had about 10% of the capacity of the battery? That would still be a large increase in the size and weight taken up by energy storage, though. It looks like just putting more batteries in the car is the economical thing to do.

If you're not going to be using the high power of a supercapacitor, there's zero reason to pay a premium.

Especially here I'd expect batteries to win out as transfer capacity is roughly proportional to storage capacity with batteries.

The UX would be invisible: If demand is greater than the supply available from the battery pack, drain some energy from the supercapacitors. If it's less, gradually shift some energy into them. If the driver is not in the vehicle, drain it all out, when they come back, recharge the supercaps.

The problem is that these capacitors and transfers add cost money, space, weight, energy, and complexity.

Looking at some numbers, batteries are ~20x more energy dense in both volume and weight. Batteries have 1/10th the power density, but efficiency drops significantly with discharge rate and they have fewer lifetime charge cycles and poorer temperature response. Batteries also have much, much lower self-discharge, and cost a lot less per kilowatt-hour.

Right now, lithium-ion batteries are simply good enough and supercapacitors are not that much better, so it's the cost-benefit analysis says it's better to take the costs you would have spent on supercaps and just put in a few more batteries.

That balance could shift, though, with improvements in supercap technology, or - paradoxically - with improvements in battery chemistry. If a battery with much better energy density and/or lower cost was found, with a reduced discharge rate that was sufficient to cruise but insufficient to accelerate or do regenerative braking, you could add supercaps to make a vehicle based on that battery feasible. It's similar to the electric grid - the base load would be handled by the slow batteries, similar to coal or nuclear power plants, while peaking loads would be handled by the supercapacitors, like a gas turbine.

You could preferentially store the regenerative braking energy into the ultracapacitors (and discharge from them from a stop, instead of the main battery). You're not talking a huge number of them (order of magnitude of ~100) for a cycle brake cycle at Model 3 mass, highway speed, and normal braking.

I don't know enough about dry battery electrode tech to know how much progress there is, how much an of an improvement they are above existing commercial technology, or who else has IP in the space.

Your response seems a bit high on the cynicism/information ratio, but I would be genuinely grateful for more information about this.