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> You want to have all your batteries inside trucks, working as much as possible, not sitting around stored at swap stations waiting to be used. Batteries don'

> You want to have all your batteries inside trucks, working as much as possible, not sitting around stored at swap stations waiting to be used. Batteries don't sit at swap stations just waiting to be used, they sit there charging. (The big difference is that the vehicle, which is also an expensive asset, doesn't have to be attached to them while doing this.) Stations will have the minimum number of batteries on hand to ensure there is always one available to swap in. Insofar as you need extra capacity to handle fluctations in usage, leading to charged batteries sitting around, you have a a strictly worse problem if the batteries are permanently attached to vehicles (since vehicle demand fluctuations don't go away, and you have the additional problem that you can't remove batteries from vehicles that aren't going to be used for a while). Another way to see this is that swappable batteries is just an extra ability; you can always charge the battery attached to the vehicle if you want. If you have a link to a technical argument for what you're trying to gesture at, I'd love to see it, but the argument you've given doesn't hold water. Arguments relating to the cost of the swapping infrastructure are at least plausible. > and recharge times aren’t really an issue. In Europe, truck drivers are required to take breaks every 4.5 hours anyway. In that case, there is no point to the overhead charging system discussed in the OP article.

Reason077 8y ago
”Stations will have the minimum number of batteries on hand to ensure there is always one available to swap in.” Therein lies the problem. You may be able to optimise your network, scheduling truck routes according to availability of swaps, etc. But it’s always going to require a substantially greater number of batteries than trucks. And for what gain? Time savings are zero-to-minimal, and fast charging is cheaper, easier, and more flexible than swapping. Also, truck batteries are going to be much bigger than car batteries. A long-range truck pack will weigh several tonnes. A station that can swap these quickly in a semi-automated way is likely to be a substantial, expensive undertaking.
- netsharc 8y ago
  Trucks already have a mechanism to attach and detach their cargo trailers, I'd imagine any battery swap feature would use this as a starting point.
- jessriedel 8y ago
  > But it’s always going to require a substantially greater number of batteries than trucks. I already addressed this is my comment. It's a loss that applies just as well to batteries that cannot be attached to vehicles, so it's not an argument against detachable batteries. > Also, truck batteries are going to be much bigger than car batteries. A long-range truck pack will weigh several tonnes. Stations already have massive underground infrastructures for dealing with fuel, which has an effective energy density that is less than a factor of two smaller than batteries. And unlike fuel, which must be stored on-site for the entire time between fuel shipments (~24 hours), you don't need to store a comparable number of batteries on site, just enough to have them continuously charging. > A station that can swap these quickly in a semi-automated way is likely to be a substantial, expensive undertaking. Putting in miles and miles of overhead charing capabilities is, I claim, significantly more expensive. But I'm not interested in having a detailed conversation on the expense of swapping machinery if we can't even agree on the simple point about utilization rates of swappable batteries being as least as large as non-swappable ones.
Reason077 8y ago
”In that case, there is no point to the overhead charging system discussed in the OP article.” In the context of long-range, fully-electric trucks, I agree. This system was designed for hybrid trucks with a short electric range.
- jessriedel 8y ago
  My point was that it doesn't make sense for you to bring up overnight charging of batteries in the context of short-electric-range trucks. If that were sufficient, we wouldn't be worrying about swapping vs. overhead charging.

Reason077 8y ago

”Stations will have the minimum number of batteries on hand to ensure there is always one available to swap in.” Therein lies the problem. You may be able to optimise your network, scheduling truck routes according to availability of swaps, etc. But it’s always going to require a substantially greater number of batteries than trucks. And for what gain? Time savings are zero-to-minimal, and fast charging is cheaper, easier, and more flexible than swapping. Also, truck batteries are going to be much bigger than car batteries. A long-range truck pack will weigh several tonnes. A station that can swap these quickly in a semi-automated way is likely to be a substantial, expensive undertaking.

netsharc 8y ago
Trucks already have a mechanism to attach and detach their cargo trailers, I'd imagine any battery swap feature would use this as a starting point.
jessriedel 8y ago
> But it’s always going to require a substantially greater number of batteries than trucks. I already addressed this is my comment. It's a loss that applies just as well to batteries that cannot be attached to vehicles, so it's not an argument against detachable batteries. > Also, truck batteries are going to be much bigger than car batteries. A long-range truck pack will weigh several tonnes. Stations already have massive underground infrastructures for dealing with fuel, which has an effective energy density that is less than a factor of two smaller than batteries. And unlike fuel, which must be stored on-site for the entire time between fuel shipments (~24 hours), you don't need to store a comparable number of batteries on site, just enough to have them continuously charging. > A station that can swap these quickly in a semi-automated way is likely to be a substantial, expensive undertaking. Putting in miles and miles of overhead charing capabilities is, I claim, significantly more expensive. But I'm not interested in having a detailed conversation on the expense of swapping machinery if we can't even agree on the simple point about utilization rates of swappable batteries being as least as large as non-swappable ones.

Reason077 8y ago

”In that case, there is no point to the overhead charging system discussed in the OP article.” In the context of long-range, fully-electric trucks, I agree. This system was designed for hybrid trucks with a short electric range.

jessriedel 8y ago
My point was that it doesn't make sense for you to bring up overnight charging of batteries in the context of short-electric-range trucks. If that were sufficient, we wouldn't be worrying about swapping vs. overhead charging.