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Huh, imagine EVs that have removable add-on batteries that you'd only plug in for the longer trips.. Like the Thinkpads with the "bigger battery" humps: https:

Huh, imagine EVs that have removable add-on batteries that you'd only plug in for the longer trips.. Like the Thinkpads with the "bigger battery" humps: https://sm.pcmag.com/t/pcmag_ap/photo/l/lenovo-thi/lenovo-thinkpad-x250-right-side-with-extended-battery_v2ga.1080.jpg https://sm.pcmag.com/t/pcmag_ap/photo/l/lenovo-thi/lenovo-th...

jopsen 2y ago
A battery trailer might affect the speed limit your allowed to drive. But it would be cool to just rent the extra 500km when needed :)
- netsharc 2y ago
  Obviously a trailer would not be a clever idea, but Nio already has cars with swappable batteries, for short distances you could just install a battery pack which is maybe 20% battery and 80% empty space https://www.youtube.com/watch?v=hNZy603as5w https://www.youtube.com/watch?v=hNZy603as5w
  - sokoloff 2y ago
    It’s enough of a pain in the ass to swap summer and winter tires, and that’s something that (some) people only do twice a year. I can’t imagine people wanting to swap battery packs (either themself or by making an appointment at a service center) before and after every long trip.
    - illiac786 2y ago
      If it’s faster than filing up, why not.
      - dboreham 2y ago
        It won't be.
        illiac786 2y ago
        Low effort reply, really, try to put in some arguments at least. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
        sokoloff 2y ago
        Both upthread replies seem to evidence approximately the same level of effort to me; "It won't be faster" isn't wildly less effort than "what if it will be faster?" Nio has fewer Nio battery swap stations operating in the entire world than just the state of New Jersey has filling stations (not dispensers, entire stations). Nothing in the video above made me think "oh wow, that looks like that process will be a lot faster than filling up!" and several segments made it seem like there would be more time involved in just getting the car into and out of the battery replacement service bay than filling up takes. (Nio's claim of a 2.5-3 minute battery swap seems to be measuring only the swap time while the car is stopped in the bay.) That's all before we consider the travel time to one of the stations (which is unlikely to be as close to your trip as a typical filling station because of the rarity of stations), time waiting for the car [or cars] in front of you to complete their swap (which if Nios ever became popular would likely be longer than waiting for one of the typically eight or more dispensers to free up at a filling station), nor to account for the "all long range batteries are out of stock at this location, because it's the Friday before Christmas and everyone is road tripping to visit family" NACKs that are liable to occur in a Nio-only battery swap system. For me the killer line in the video that will make it hard for Nio to solve all of these is at https://www.youtube.com/watch?v=hNZy603as5w&t=270s https://www.youtube.com/watch?v=hNZy603as5w&t=270s : "Building these stations is incredibly expensive and it's no secret that Nio is losing a staggering amount of money right now..."
        illiac786 2y ago
        My point is, it may be interesting if it’s faster than filing up. Now, is it likely? Not at the moment, as you correctly pointed out. Can I guarantee it will never happen? No. Hence my comment. It was not about stating what will happen or not, I don’t feel this type of prediction has any reliability. Millions of people smarter than me get it wrong every day, especially the very long term ones are almost always wrong.
    - ljf 2y ago
      Ideally they could just come to my home or workplace and swap the batteries out there while I am doing something else (if it is going to take longer than 30 mins)
  - dboreham 2y ago
    Having done a long trip in an EV, in a very inhospitable location (the USA, without access to Tesla chargers), I'm not convinced there is an EV range/charge time problem. I think it's mostly in the minds of the public. Hence I'm skeptical that the changeable battery pack is a solution to any problem. My experience was that you end up stopping to charge a bit more often than you'd stop to fill up gas, but factoring in stops for bathroom and food, it's really not a significant difference. There just needs to be more chargers (to avoid queuing for an open one), and chargers that are more closely spaced (every 50 miles like gas stations instead of every 100+ miles). Then today's EVs will be just fine for long trips. Not completely perfect, but perfectly adequate, to the point that it won't be worthwhile buying an ICE vehicle just to have it for long trips.
    - Mawr 2y ago
      Yep, people use their cars for 50 miles/day for commuting and such, but when buying an EV they think of the 4 long trips they make a year.
- wtallis 2y ago
  Speed limits for towing smaller trailers mostly derive from safety concerns about overloaded or imbalanced trailers being unstable at high speeds. A battery-only trailer with little or no cargo space, designed and certified in conjunction with specific tow vehicles, could easily be safe enough to operate at highway speeds. I think the main reason why we don't see anyone seriously pursuing the battery trailer idea is that it would be an expensive niche product. It would have to be mostly a rental-only product, and offer few advantages over simply renting a more suitable vehicle.
rangestransform 2y ago
This is a stupid idea because you’d have to make fasteners and high voltage interfaces that can survive an order of magnitude more cycles than they have to for a fixed pack. It would also be significantly more difficult to use the pack as a stressed member of the car structure. It’s better to just have less batteries and use them more efficiently through weight savings.
- Earw0rm 2y ago
  Don't the charging ports already have to do that?
- bcrl 2y ago
  Do you realize that one of the reasons for the swappable batteries on various Thinkpads is so that you can hot swap batteries without powering down or rebooting? I've never had an issue with the connectors for the batteries of the ThinkPad, and being able to swap in a spare fully charged battery has been very helpful many times when out doing field working all day long. What is an issue are the little plastic tabs on the batteries that break off over time. However, usually the batteries have already lost a lot of their lifespan by the time that happens, and since the batteries are removable they can be replaced without opening up the system or melting glue with heat as is the case on most modern cell phones. Seems like a win to me!
  - sightbroke 2y ago
    I could be wrong but the currents and voltages for EVs are rather bit more dangerous and taxing than that typically found used in laptops. Which I think the person you replied was partially attempting to point out.
    - bcrl 2y ago
      My point is that hot swappable battery packs have benefits that outweigh the cost of the connectors for the people that have a use case that needs them, as the grandparent referred to in Thinkpads. Not everyone fits in the constraints of design space chosen for a given product. There's a reason virtually every modern computer has a means of adding expansion devices. Making a high voltage connector is well understood problem space. Every electrical engineer knows how to deal with ramping up current when a power supply is plugged in or turned on (inrush current specifications are most definitely a thing), and the entire electric grid is based on sizing, insulating, spacing and switching conductors appropriately for the voltage and current being used. Moreover, high voltage battery packs tend to have switches / contactors on the battery pack that keep the high voltage off until the connection is securely made and enabled, hence why even Telsas require a functioning low voltage battery to start the system. There are also certain use-cases that are likely best served by putting battery packs in a trailer. Take the trucking industry: going by the charging requirements of a Tesla semi (1MW for 30 minutes), replicating your typical truck stop turns into a huge problem for the grid -- you'd need upwards of 50MW of charging capacity to replicate the flow of diesel coming out of a bank of 10 fuel pumps (sorry, I ran the thought experiment on that one back when specs were first released). Having a battery pack attached to the trailer that gets charged at a more leisurely rate at the warehouse while it is unloaded and re-loaded over a couple of hours is far more scalable than charging the truck in a few minutes at a truck stop. Charging overnight while the driver sleeps is fine, but getting the 8-12 hours of runtime for a workday in a semi is a heck of a lot of battery. The dangers can be mitigated -- that's the entire raison d'etre of the electrical engineering discipline! Otherwise you wouldn't be able to safely charge an electric car at a 350kW rate these days at charging stations all over the world with a connector that is deemed safe to be handled by random humans. It's not like the software industry where we throw half baked shit at the wall and see what sticks when users encounter it by running an A / B test in production....
ianleighton 2y ago
NIO does battery swaps in minutes, in China and Europe. I believe you can also perhaps get different ranges but if not, would be great to swap between a 50kwh pack for normal use and say 100+kwh for your road trip. Then again battery charging/weight tech is getting pretty good pretty fast.
usrusr 2y ago
I imagine semiautonomous trailers that would just tag along in the slipstream within cable range for distances beyond your daily. With computer-fast reaction to brake and steering inputs of the lead car. Those would universally be rentals that you change like the horses in pre-rail post networks.
ndsipa_pomu 2y ago
It surprises me how much people are determined to use the "car" form factor when it's clearly not a good design for weight reduction and efficient transport. If instead people consider EVs that are non-car-shaped then we get things like e-bikes and e-scooters. Both can feature easily swappable batteries as the batteries are so much smaller due to the reduced weight of the vehicle. Also, the problems around congestion can pretty much disappear when you get enough people to use an e-bike/e-scooter instead of a car. The tyre wear/pollution is minimised due to the reduction in weight and similarly the brakes.

jopsen 2y ago

A battery trailer might affect the speed limit your allowed to drive. But it would be cool to just rent the extra 500km when needed :)

netsharc 2y ago
Obviously a trailer would not be a clever idea, but Nio already has cars with swappable batteries, for short distances you could just install a battery pack which is maybe 20% battery and 80% empty space https://www.youtube.com/watch?v=hNZy603as5w https://www.youtube.com/watch?v=hNZy603as5w
- sokoloff 2y ago
  It’s enough of a pain in the ass to swap summer and winter tires, and that’s something that (some) people only do twice a year. I can’t imagine people wanting to swap battery packs (either themself or by making an appointment at a service center) before and after every long trip.
  - illiac786 2y ago
    If it’s faster than filing up, why not.
    - dboreham 2y ago
      It won't be.
      - illiac786 2y ago
        Low effort reply, really, try to put in some arguments at least. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
        sokoloff 2y ago
        Both upthread replies seem to evidence approximately the same level of effort to me; "It won't be faster" isn't wildly less effort than "what if it will be faster?" Nio has fewer Nio battery swap stations operating in the entire world than just the state of New Jersey has filling stations (not dispensers, entire stations). Nothing in the video above made me think "oh wow, that looks like that process will be a lot faster than filling up!" and several segments made it seem like there would be more time involved in just getting the car into and out of the battery replacement service bay than filling up takes. (Nio's claim of a 2.5-3 minute battery swap seems to be measuring only the swap time while the car is stopped in the bay.) That's all before we consider the travel time to one of the stations (which is unlikely to be as close to your trip as a typical filling station because of the rarity of stations), time waiting for the car [or cars] in front of you to complete their swap (which if Nios ever became popular would likely be longer than waiting for one of the typically eight or more dispensers to free up at a filling station), nor to account for the "all long range batteries are out of stock at this location, because it's the Friday before Christmas and everyone is road tripping to visit family" NACKs that are liable to occur in a Nio-only battery swap system. For me the killer line in the video that will make it hard for Nio to solve all of these is at https://www.youtube.com/watch?v=hNZy603as5w&t=270s https://www.youtube.com/watch?v=hNZy603as5w&t=270s : "Building these stations is incredibly expensive and it's no secret that Nio is losing a staggering amount of money right now..."
        illiac786 2y ago
        My point is, it may be interesting if it’s faster than filing up. Now, is it likely? Not at the moment, as you correctly pointed out. Can I guarantee it will never happen? No. Hence my comment. It was not about stating what will happen or not, I don’t feel this type of prediction has any reliability. Millions of people smarter than me get it wrong every day, especially the very long term ones are almost always wrong.
  - ljf 2y ago
    Ideally they could just come to my home or workplace and swap the batteries out there while I am doing something else (if it is going to take longer than 30 mins)
- dboreham 2y ago
  Having done a long trip in an EV, in a very inhospitable location (the USA, without access to Tesla chargers), I'm not convinced there is an EV range/charge time problem. I think it's mostly in the minds of the public. Hence I'm skeptical that the changeable battery pack is a solution to any problem. My experience was that you end up stopping to charge a bit more often than you'd stop to fill up gas, but factoring in stops for bathroom and food, it's really not a significant difference. There just needs to be more chargers (to avoid queuing for an open one), and chargers that are more closely spaced (every 50 miles like gas stations instead of every 100+ miles). Then today's EVs will be just fine for long trips. Not completely perfect, but perfectly adequate, to the point that it won't be worthwhile buying an ICE vehicle just to have it for long trips.
  - Mawr 2y ago
    Yep, people use their cars for 50 miles/day for commuting and such, but when buying an EV they think of the 4 long trips they make a year.
wtallis 2y ago
Speed limits for towing smaller trailers mostly derive from safety concerns about overloaded or imbalanced trailers being unstable at high speeds. A battery-only trailer with little or no cargo space, designed and certified in conjunction with specific tow vehicles, could easily be safe enough to operate at highway speeds. I think the main reason why we don't see anyone seriously pursuing the battery trailer idea is that it would be an expensive niche product. It would have to be mostly a rental-only product, and offer few advantages over simply renting a more suitable vehicle.

rangestransform 2y ago

This is a stupid idea because you’d have to make fasteners and high voltage interfaces that can survive an order of magnitude more cycles than they have to for a fixed pack. It would also be significantly more difficult to use the pack as a stressed member of the car structure. It’s better to just have less batteries and use them more efficiently through weight savings.

Earw0rm 2y ago
Don't the charging ports already have to do that?
bcrl 2y ago
Do you realize that one of the reasons for the swappable batteries on various Thinkpads is so that you can hot swap batteries without powering down or rebooting? I've never had an issue with the connectors for the batteries of the ThinkPad, and being able to swap in a spare fully charged battery has been very helpful many times when out doing field working all day long. What is an issue are the little plastic tabs on the batteries that break off over time. However, usually the batteries have already lost a lot of their lifespan by the time that happens, and since the batteries are removable they can be replaced without opening up the system or melting glue with heat as is the case on most modern cell phones. Seems like a win to me!
- sightbroke 2y ago
  I could be wrong but the currents and voltages for EVs are rather bit more dangerous and taxing than that typically found used in laptops. Which I think the person you replied was partially attempting to point out.
  - bcrl 2y ago
    My point is that hot swappable battery packs have benefits that outweigh the cost of the connectors for the people that have a use case that needs them, as the grandparent referred to in Thinkpads. Not everyone fits in the constraints of design space chosen for a given product. There's a reason virtually every modern computer has a means of adding expansion devices. Making a high voltage connector is well understood problem space. Every electrical engineer knows how to deal with ramping up current when a power supply is plugged in or turned on (inrush current specifications are most definitely a thing), and the entire electric grid is based on sizing, insulating, spacing and switching conductors appropriately for the voltage and current being used. Moreover, high voltage battery packs tend to have switches / contactors on the battery pack that keep the high voltage off until the connection is securely made and enabled, hence why even Telsas require a functioning low voltage battery to start the system. There are also certain use-cases that are likely best served by putting battery packs in a trailer. Take the trucking industry: going by the charging requirements of a Tesla semi (1MW for 30 minutes), replicating your typical truck stop turns into a huge problem for the grid -- you'd need upwards of 50MW of charging capacity to replicate the flow of diesel coming out of a bank of 10 fuel pumps (sorry, I ran the thought experiment on that one back when specs were first released). Having a battery pack attached to the trailer that gets charged at a more leisurely rate at the warehouse while it is unloaded and re-loaded over a couple of hours is far more scalable than charging the truck in a few minutes at a truck stop. Charging overnight while the driver sleeps is fine, but getting the 8-12 hours of runtime for a workday in a semi is a heck of a lot of battery. The dangers can be mitigated -- that's the entire raison d'etre of the electrical engineering discipline! Otherwise you wouldn't be able to safely charge an electric car at a 350kW rate these days at charging stations all over the world with a connector that is deemed safe to be handled by random humans. It's not like the software industry where we throw half baked shit at the wall and see what sticks when users encounter it by running an A / B test in production....

ianleighton 2y ago

NIO does battery swaps in minutes, in China and Europe. I believe you can also perhaps get different ranges but if not, would be great to swap between a 50kwh pack for normal use and say 100+kwh for your road trip. Then again battery charging/weight tech is getting pretty good pretty fast.

usrusr 2y ago

I imagine semiautonomous trailers that would just tag along in the slipstream within cable range for distances beyond your daily. With computer-fast reaction to brake and steering inputs of the lead car. Those would universally be rentals that you change like the horses in pre-rail post networks.

ndsipa_pomu 2y ago

It surprises me how much people are determined to use the "car" form factor when it's clearly not a good design for weight reduction and efficient transport. If instead people consider EVs that are non-car-shaped then we get things like e-bikes and e-scooters. Both can feature easily swappable batteries as the batteries are so much smaller due to the reduced weight of the vehicle. Also, the problems around congestion can pretty much disappear when you get enough people to use an e-bike/e-scooter instead of a car. The tyre wear/pollution is minimised due to the reduction in weight and similarly the brakes.