4 ms·

All of the comments re: swappable battery packs are missing the end goal. Once the driver is gone from autonomy, these fleets are going to be dirt cheap to oper

by tyrw 9y ago

All of the comments re: swappable battery packs are missing the end goal. Once the driver is gone from autonomy, these fleets are going to be dirt cheap to operate. It won't make sense to swap a battery pack when you can just park one truck on the charger and let another take its place.

tyrw 9y ago
I'd also add that virtually the only compelling reason to have a single, large load like a big rig is to minimize the cost of a human driver relative to payload shipped. Without a driver, the optimal load size will likely be much different and will vary more by industry than it does today.
- mdorazio 9y ago
  Yes and no. Cost of fuel is also a big factor. A big rig is typically running about 6 MPG, and for lighter loads that doesn't change very much if you're hauling a half-size or full-size container. Sending two trucks means burning twice as much fuel, which could easily be hundreds of dollars. But definitely that's less of a factor with an electric truck since the charging cost will be a lot lower than a comparable amount of fuel.
  - tyrw 9y ago
    Cost of fuel will also be greatly reduced for the use cases within electric range: - Removing the driver allows for more aerodynamic cab configuration, or no cab at all - Electric motors are more efficient, particularly in high-torque / low-rpm environment - Massive & inefficient 18-speed gearbox can be avoided - Cost of fuel itself (electricity) is much cheaper
    - patrickg_zill 9y ago
      I think the bigger savings will come in being able to precisely control stops, starts, and turning, which will both minimize damage to the road surface and lengthen tire life. ISTR a case where a large open pit mine bought GPS-driven trucks and saved a great deal just from longer tire life (each tire was $20K).
    - derefr 9y ago
      Re: gearbox, I wonder whether an autonomous truck could be paired with a little scouting drone to "look ahead" at things like blind corners or stop-and-go traffic, to allow the truck enough foreknowledge to gear up and down more gradually.
- rgbrenner 9y ago
  If anything, wouldn't the loads get larger.. since you could build trailers with more sensors, allowing more trailers to be attached to the same tractor... minimizing energy/fuel cost. One tractor carrying larger loads is going to be more efficient than many small trucks with smaller loads: total weight over payload. A human being can only safely handle so much cargo, and that's probably lower than could be automated.
  - JBReefer 9y ago
    The limit on truck size isn't because of human driving capacity, it's because road damage scales as the fourth power of axle weight. Trucks already do the vast majority of damage to our infrastructure, increasing the weight more would literally take down some older bridges.
    - rgbrenner 9y ago
      I was referring to more trailers like this: http://www.hankstruckpictures.com/pix/trucks/macneil/2004/mar/mar23/watkins_t2.jpg http://www.hankstruckpictures.com/pix/trucks/macneil/2004/ma... That doesn't require an increase in axle weight
      - stock_toaster 9y ago
        I seem to recall hearing that some states have restrictions on trailer count. Presumably due to road safety issues.
  - fpgaminer 9y ago
    Hmmm, I'm not sure the equation is so obvious. If you don't have a driver, then the vehicle amounts to just a couple motors, batteries, and sensor arrays. It doesn't make a difference if the battery is located in the front "truck" part of the convoy, or whether it's distributed throughout the trailers. For a very long chain of trailers, you probably want a set of motors for every trailer right? And as you've speculated, there's going to be a sensor array in every trailer. So basically, you have motors in every trailer, batteries in every trailer, and sensors in every trailer. At that point ... why do you need a "truck" on the front and/or why are they connected at all?
rhino369 9y ago
It's still a hell of a lot cheaper to have 2 batteries and 1 truck than 2 batteries in two trucks, assuming switching cost isn't too high.
colechristensen 9y ago
>It won't make sense to swap a battery pack when you can just park one truck on the charger and let another take its place. That depends on the relative capital costs of a truck sitting idle for hours while it charges and the costs of the systems for swapping and charging batteries. It's the difference between making every truck and charging station a little more complex and making every station significantly larger and increasing the number of trucks you need to own.
pkaler 9y ago
> It won't make sense to swap a battery pack when you can just park one truck on the charger and let another take its place. I'm guessing an operator would want 100% utilization from a truck. If a battery discharges at the same rate as charging, then you would need 2x the number of batteries. You would need more batteries if charging is slower than discharging.
- tyrw 9y ago
  More accurately, an operator will want lowest cost of operation. You can add complexity, cost, and failure modes to every single truck by making the battery swappable, then build infrastructure to swap the batteries, or you can just build more trucks. Given that wheels and axles are likely to be the cheapest part of the equation, I'm betting they'll buy more trucks.
- otp124 9y ago
  I remember hearing there is not enough lithium in the world for all of Tesla's ambitions. They're hoping for battery revolutions
  - Baeocystin 9y ago
    I found an excellent Quora answer that dealt directly with this. Well worth a look-over. https://www.quora.com/Is-there-enough-lithium-in-the-world-to-replace-all-petroleum-cars-with-battery-electric-vehicles-How-many-car-battery-packs-can-we-manufacture-given-the-resources-available https://www.quora.com/Is-there-enough-lithium-in-the-world-t... tl;dr- Lithium supply (in terms of raw quantity of element available) is not going to be an issue, ever. Economical extraction might be.
    - eru 9y ago
      And you can make batteries out of other materials. At current prices lithium might be best, but more demand will lead to different prices; and if lithium supply doesn't pick up, people will substitute.
refurb 9y ago
Capital costs? If a truck can only operate 50% of the time because the other 50% is spent recharging, you'll need twice as many trucks to move the same load. While those trucks are recharging you're still paying for them.
- eru 9y ago
  Depends on how expensive the battery is compared to the rest of the truck.
vonmoltke 9y ago
> Once the driver is gone from autonomy, these fleets are going to be dirt cheap to operate. What gives you the impression that human drivers are such a large part of the costs now?
- nkurz 9y ago
  I don't know whether it counts as "such a large part of the costs", but at least in the US it does appear that wages and fuel are about equal as the two major costs: While fuel costs were historically the largest share of total cost, driver wages surpassed fuel as the largest share at 31 percent of total cost in 2015, and fuel now accounts for 25 percent – its lowest share since the inception of this study. Fuel was followed by equipment lease or purchase payments at 14 percent, with repair and maintenance, insurance premiums, permits and license, tires, toll costs, and driver benefits each representing 10 percent or less of average total marginal costs. http://atri-online.org/wp-content/uploads/2016/10/ATRI-Operational-Costs-of-Trucking-2016-09-2016.pdf http://atri-online.org/wp-content/uploads/2016/10/ATRI-Opera... Tables 10, 11, and 12 show a more exact breakdown. If all else remained the same, removing the driver would appear to reduce total costs by 40% (30% wages plus 10% benefits). So unless the electricity is much cheaper than diesel it won't be "dirt cheap", but certainly would be a significant reduction.
  - TheReveller 9y ago
    Reducing costs has a large effect on profits. If your profit margin is 5% then reducing costs by 10% triples your margin.
  - eru 9y ago
    Removing the driver will also help with capital costs: trucks running 24/7 can spread those out over more hours.
    - marcosdumay 9y ago
      Not if those trucks must stay most of their time parked for charging.
marcosdumay 9y ago
It is almost certainly cheaper to have big motors centralized at a single unit, because motors scale faster than linearly with size. It is also almost certainly cheaper to have small batteries spread through the train, because batteries scale mostly linearly, but there are a few problems with dense packs (like cooling). Thus, if you want to plug the unities one into the other, you will probably have one or two powered unities, many cargo unities, and a few battery unities spread between them. Besides, you will also want dummy unities on the front and back with aerodynamic shapes.

by tyrw 9y ago

tyrw 9y ago

I'd also add that virtually the only compelling reason to have a single, large load like a big rig is to minimize the cost of a human driver relative to payload shipped. Without a driver, the optimal load size will likely be much different and will vary more by industry than it does today.

mdorazio 9y ago
Yes and no. Cost of fuel is also a big factor. A big rig is typically running about 6 MPG, and for lighter loads that doesn't change very much if you're hauling a half-size or full-size container. Sending two trucks means burning twice as much fuel, which could easily be hundreds of dollars. But definitely that's less of a factor with an electric truck since the charging cost will be a lot lower than a comparable amount of fuel.
- tyrw 9y ago
  Cost of fuel will also be greatly reduced for the use cases within electric range: - Removing the driver allows for more aerodynamic cab configuration, or no cab at all - Electric motors are more efficient, particularly in high-torque / low-rpm environment - Massive & inefficient 18-speed gearbox can be avoided - Cost of fuel itself (electricity) is much cheaper
  - patrickg_zill 9y ago
    I think the bigger savings will come in being able to precisely control stops, starts, and turning, which will both minimize damage to the road surface and lengthen tire life. ISTR a case where a large open pit mine bought GPS-driven trucks and saved a great deal just from longer tire life (each tire was $20K).
  - derefr 9y ago
    Re: gearbox, I wonder whether an autonomous truck could be paired with a little scouting drone to "look ahead" at things like blind corners or stop-and-go traffic, to allow the truck enough foreknowledge to gear up and down more gradually.
rgbrenner 9y ago
If anything, wouldn't the loads get larger.. since you could build trailers with more sensors, allowing more trailers to be attached to the same tractor... minimizing energy/fuel cost. One tractor carrying larger loads is going to be more efficient than many small trucks with smaller loads: total weight over payload. A human being can only safely handle so much cargo, and that's probably lower than could be automated.
- JBReefer 9y ago
  The limit on truck size isn't because of human driving capacity, it's because road damage scales as the fourth power of axle weight. Trucks already do the vast majority of damage to our infrastructure, increasing the weight more would literally take down some older bridges.
  - rgbrenner 9y ago
    I was referring to more trailers like this: http://www.hankstruckpictures.com/pix/trucks/macneil/2004/mar/mar23/watkins_t2.jpg http://www.hankstruckpictures.com/pix/trucks/macneil/2004/ma... That doesn't require an increase in axle weight
    - stock_toaster 9y ago
      I seem to recall hearing that some states have restrictions on trailer count. Presumably due to road safety issues.
- fpgaminer 9y ago
  Hmmm, I'm not sure the equation is so obvious. If you don't have a driver, then the vehicle amounts to just a couple motors, batteries, and sensor arrays. It doesn't make a difference if the battery is located in the front "truck" part of the convoy, or whether it's distributed throughout the trailers. For a very long chain of trailers, you probably want a set of motors for every trailer right? And as you've speculated, there's going to be a sensor array in every trailer. So basically, you have motors in every trailer, batteries in every trailer, and sensors in every trailer. At that point ... why do you need a "truck" on the front and/or why are they connected at all?

rhino369 9y ago

It's still a hell of a lot cheaper to have 2 batteries and 1 truck than 2 batteries in two trucks, assuming switching cost isn't too high.

colechristensen 9y ago

>It won't make sense to swap a battery pack when you can just park one truck on the charger and let another take its place. That depends on the relative capital costs of a truck sitting idle for hours while it charges and the costs of the systems for swapping and charging batteries. It's the difference between making every truck and charging station a little more complex and making every station significantly larger and increasing the number of trucks you need to own.

pkaler 9y ago

> It won't make sense to swap a battery pack when you can just park one truck on the charger and let another take its place. I'm guessing an operator would want 100% utilization from a truck. If a battery discharges at the same rate as charging, then you would need 2x the number of batteries. You would need more batteries if charging is slower than discharging.

tyrw 9y ago
More accurately, an operator will want lowest cost of operation. You can add complexity, cost, and failure modes to every single truck by making the battery swappable, then build infrastructure to swap the batteries, or you can just build more trucks. Given that wheels and axles are likely to be the cheapest part of the equation, I'm betting they'll buy more trucks.
otp124 9y ago
I remember hearing there is not enough lithium in the world for all of Tesla's ambitions. They're hoping for battery revolutions
- Baeocystin 9y ago
  I found an excellent Quora answer that dealt directly with this. Well worth a look-over. https://www.quora.com/Is-there-enough-lithium-in-the-world-to-replace-all-petroleum-cars-with-battery-electric-vehicles-How-many-car-battery-packs-can-we-manufacture-given-the-resources-available https://www.quora.com/Is-there-enough-lithium-in-the-world-t... tl;dr- Lithium supply (in terms of raw quantity of element available) is not going to be an issue, ever. Economical extraction might be.
  - eru 9y ago
    And you can make batteries out of other materials. At current prices lithium might be best, but more demand will lead to different prices; and if lithium supply doesn't pick up, people will substitute.

refurb 9y ago

Capital costs? If a truck can only operate 50% of the time because the other 50% is spent recharging, you'll need twice as many trucks to move the same load. While those trucks are recharging you're still paying for them.

eru 9y ago
Depends on how expensive the battery is compared to the rest of the truck.

vonmoltke 9y ago

> Once the driver is gone from autonomy, these fleets are going to be dirt cheap to operate. What gives you the impression that human drivers are such a large part of the costs now?

nkurz 9y ago
I don't know whether it counts as "such a large part of the costs", but at least in the US it does appear that wages and fuel are about equal as the two major costs: While fuel costs were historically the largest share of total cost, driver wages surpassed fuel as the largest share at 31 percent of total cost in 2015, and fuel now accounts for 25 percent – its lowest share since the inception of this study. Fuel was followed by equipment lease or purchase payments at 14 percent, with repair and maintenance, insurance premiums, permits and license, tires, toll costs, and driver benefits each representing 10 percent or less of average total marginal costs. http://atri-online.org/wp-content/uploads/2016/10/ATRI-Operational-Costs-of-Trucking-2016-09-2016.pdf http://atri-online.org/wp-content/uploads/2016/10/ATRI-Opera... Tables 10, 11, and 12 show a more exact breakdown. If all else remained the same, removing the driver would appear to reduce total costs by 40% (30% wages plus 10% benefits). So unless the electricity is much cheaper than diesel it won't be "dirt cheap", but certainly would be a significant reduction.
- TheReveller 9y ago
  Reducing costs has a large effect on profits. If your profit margin is 5% then reducing costs by 10% triples your margin.
- eru 9y ago
  Removing the driver will also help with capital costs: trucks running 24/7 can spread those out over more hours.
  - marcosdumay 9y ago
    Not if those trucks must stay most of their time parked for charging.

marcosdumay 9y ago

It is almost certainly cheaper to have big motors centralized at a single unit, because motors scale faster than linearly with size. It is also almost certainly cheaper to have small batteries spread through the train, because batteries scale mostly linearly, but there are a few problems with dense packs (like cooling). Thus, if you want to plug the unities one into the other, you will probably have one or two powered unities, many cargo unities, and a few battery unities spread between them. Besides, you will also want dummy unities on the front and back with aerodynamic shapes.