We'd need a breakthrough in battery technology, or some improved supercapacitors, or productionization of flywheels, to be able to take advantage of that energy.
Its really freeing not to have to look at the regen gauge at all, I just keep my foot over the brake pedal just in case I need to stop quicker than the regen braking.
Supercaps are 28800 Joules per liter, so you'd be needing nearly 700 liters of them to store the energy of the car decelerating from 60 mph once.
700 liters is a lot of volume in a car where you already use a lot of the available volume for batteries - it's more than the trunk and frunk combined on a Model3.
For personal vehicles it makes a lot more sense, particularly when you realize using regen braking means less brake and battery wear so it helps lower maintenance. I do similar things with the fuel economy gauge in my car.
So the interesting question is can operating costs make their way into the incentive structure (theoretically it should be able to with good vehicle telemetry).
Whether it's worth it or not to adopt that incentive structure is another question: is the cost of fuel and maintenance greater or less than the marginal revenue from each additional package? Because you're right, currently the incentives are infamous for maximizing number of deliveries. However, the famous UPS-minimize-left-turns routing optimization story suggests operating costs do factor in as well.
It would likely be easier to just increase vehicle efficiency in the form of better braking, lighter vehicles, higher battery density, etc.
Is this something you have numbers on or just seat of the pants math? Most mileage numbers for electric cars are much better in city driving with start/ stop conditions so I'm a bit skeptical about your methods.
When you hit the brakes on a regenerative-braking hybrid, you will see a bar start to fill up. The bar is divided into two sections.
If you tap the brakes, the bar only fills up a little, and stays in the left section. That means that your regenerative brakes are slowing you.
If you slam the brakes, the bar fills up fully, and is way in the right section. That means that your friction brakes are slowing you.
If you drive 'normally' - like most other people drive, you will never keep the bar in the left section during braking. It will always be half-way in the right section. This means you are wasting ~half of your braking energy, as friction and heat.
If you drive very smoothly, with no sudden braking, you can keep the bar almost constantly in the left section. But this requires you to start braking a lot earlier than most drivers, when you see, say, a red light.
This isn't a bad thing, since smoother acceleration/braking reduces traffic jams, but it's not how most people drive.
In practice, I have observed that the difference between these two forms of driving (Aggressive braking + accelleration, smooth braking + accelleration) is the difference between ~43 MPG and ~48MPG.
Regenerative braking improves efficiency even without careful driving, additionally you can drive carefully and improve your efficiency even more. This isn't the same as suggesting current regenerative braking isn't "good enough" for start stop applications.
Braking will always involve energy loss, that's just physics. Over time we can improve how much energy is regained during braking but again that it can be better does not prove that it's not worthwhile now.
I've never said it doesn't help. When the bar is in the right section, that means that your regenerative braking is operating at peak capacity, with extra friction braking applied on top.
> Braking will always involve energy loss, that's just physics. Over time we can improve how much energy is regained during braking but again that it can be better does not prove that it's not worthwhile now.
The energy loss of regenerative braking is some XY%. The energy loss of friction braking is 100%.
The optimal way to drive with regenerative braking is slow and steady braking. So that you are eating XY% energy loss in your braking energy, and not "Partially XY%, partially 100%". Most people drive in a way that would put them in the latter category.
As another poster mentioned, its quite possible for cars with $10,000 batteries to usefully absorb more energy through their regenerative braking.
I'm not really sure what your point is or where your comments fit into this conversation at this point.
And I'm pretty sure your meter is measuring KW, not Wh. Regardless, I question its accuracy in our Leaf. How thick is the cable taking the 30KW and putting it in the batter, when the on-board charger on that thing only puts out 3.3KW? And maybe the answer is, "as thick as your wrist, but it's very short"), dunno, but color me skeptical.
The main inverter is going between motor voltage and pack voltage, and depending on the car can handle regeneration at upwards of 60 kW (Teslas) to 265 kW (Porsche Taycan).
The cable that is putting 30 kW into the battery? It's the same one that's designed to conduct 80-110 kW from battery to motor in your Leaf.
https://youtu.be/KAIzAlgHF2E?t=57s
It measures regenerated Wh. In my case it was in increments of 30Wh.
How thick is the cable taking the 30KW and putting it in the batter, when the on-board charger on that thing only puts out 3.3KW?
As thick as the one putting 100kW into the motor I guess, so at 300V - not very thick.
Skeptical of what exactly?
Even if the benefits of regenerative braking were zero, electric vehicles still make sense for delivery vans. They have known ranges, usually less than 100 miles and the reduction fuel and maintenance costs will be huge. This is why there is so much interest in the Tesla semi and other similar tech where regenerative braking has nearly little effect on milage because the vehicles aren't stopping often.
But existing driving data suggests there will be some non-zero effect on efficiency through regenerative braking so I'm not sure what the point here is.
You see the traffic slowing down, foot off the pedal, regen starts and the car slows down. Traffic gets going again, push the pedal.
If you drive a hybrid/PHEV/EV like you would an ICE, it won't be economical.
I think to get the power from more sudden stops, you'd need to have some kind of intermediate storage (like a capacitor bank) that could hold that energy for 20-30 seconds while it's streamed at the appropriate rate back into the main battery.
https://www.tesla.com/en_CA/blog/magic-tesla-roadster-regene...
I will note that the homebuilt electric cars generally had much smaller battery packs, which could not supply the same peak currents that a 50+kWh battery would have.
Does it really require a lot more than 300KW to stop a UPS truck on an average start-stop (traffic light or stop sign) situation?
It just doesn't seem like the issue of being able to disappate the energy with regenerative brakes would be a real problem with a full EV delivery vehicle. I think the people pointing to it as an issue are thinking of either different battery tech or hybrid delivery vehicles that had much smaller batteries (and thus lower peak regen).
But that's not the only way to define good enough that might be relevant here.
Many electric vehicles have a greater range in city traffic than they have on the highway, which is the opposite of how it is for ICE vehicles. So that means the benefit is quite significant, enough to help with cost savings.
Also, stop/start driving creates a lot of wear and tear on brakes. Maintaining brakes is probably a significant part of operating costs. If regenerative braking can reduce those costs, even if it doesn't eliminate them, it could still be significant.
All that's required is storage for ~35mph to 0, and you get 95% regen instead of 10%.
Can still shunt to the battery on long descents, but for UPS, this would be perfect.