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Why can't battery tech achieve this? I have a very old petrol car (>35y) with a terrible fuel-indicator. I bring a spare 5L tank with petrol under the backseat

by berkes 3y ago

Why can't battery tech achieve this? I have a very old petrol car (>35y) with a terrible fuel-indicator. I bring a spare 5L tank with petrol under the backseat always. An EV could achieve the same with a small portable powerbank, not? My current tank can hold some 50+L; this gives my old T3 a range of ~430km¹. When we lived in Botswana ('83, other car) we had an extra 150L spare fuel-tank instead of back-seats. We could do some 1500km in this old 4wd on full tanks. Which was needed as gas-pumps were easily 300km apart and often out of gas. An EV could achieve the same with the back-seats replaced by additional battery-packs, not? I'd presume this might be too heavy or not allowed due to regulations, but technically just adding ridiculous amounts of batteries would solve this. Like adding ridiculous tanks for gas would. Sure, the amount of joules you can pack in a KG of fuel is far more than in a KG of batteries. But to me the solution then is easy: just add more KGs. ¹yup, the mileage is terrible, a VW T3 is basically an underpowered, 1500kg brick

pjc50 3y ago
You know, I don't think I've seen this idea before. I've seen discussion of "can we swap the whole battery pack at a station", "can we make the cells pourable", people carrying generators, etc., but I've not seen the idea of a removable part of power pack for limp-home situations. A modern equivalent of the Jerry can.
mlyle 3y ago
> I bring a spare 5L tank with petrol under the backseat always. Not too safe of an idea... > An EV could achieve the same with a small portable powerbank, not? Say that tank gets you 70km. You'd need 15 kilowatt-hours or 54 megajoules of battery, or about 56kg and about 25L of volume to do the same. > An EV could achieve the same with the back-seats replaced by additional battery-packs, not? I'd presume this might be too heavy or not allowed due to regulations, but technically just adding ridiculous amounts of batteries would solve this. Maybe, but it's also ridiculous amounts of money. Also, really increasing the mass of the vehicle is enough to hurt efficiency, so...
- AlexandrB 3y ago
  I would love to see some kind of standardized way of supplementing an electric car's battery. Most people don't need massive EV range all of the time, just when going on long trips. Being able to buy or rent an extra battery pack and throw it in the trunk, frunk, or back seats to add more range seems ideal for those cases.
  - BizarroLand 3y ago
    I've thought it would be great if there were rentable battery trailers that had an extra full charge or two built in, plus maybe some extra storage. uHaul could make a killing off of them for people who want to take their EV on a road trip. If you could get 600 miles off of a single combined full charge you would be in the range of reasonable American road trip distance, and you could make the choice to stop and eat and occupy two chargers to get another 480 miles or so out of a 30 minute stop. I usually clock about 900-1100 miles a day when I'm doing a destination road trip, so I would still chafe at that limit, but it would beat the heck out of sub-300 mile limits between long breaks for me.
    - mlyle 3y ago
      Even with a smaller trailer, though, I'd expect a 33% or so range penalty-- it's just not too much of a win. You don't make it anywhere near twice as far.
      - BizarroLand 3y ago
        Even so, assuming there were a nationwide network of them, you could pull in, swap trailers, and be on your way in 15 minutes. Of course, this is in an ideal world where everything goes my way. I wonder if the penalty would be as high as 33%. Seems like it would be simple to make a maximally aerodynamic battery trailer since human comfort doesn't have to be considered. Then you're only adding the weight and drag of a few hundred lbs of trailer and battery. I would think the penalty would be in the high single digits or at most in the very low double digits which could be offset by having 1.5x or 2x normal battery capacity in the trailer. *Ninja edit, I decided to look this up. The Model Y's battery is 1700 lbs, so you are absolutely right that there would be a significant distance penalty adding that much weight to the vehicle plus the trailer weight and the battery armor as well if that isn't included in the weight. https://www.carparts.com/blog/how-heavy-is-a-tesla-battery/ https://www.carparts.com/blog/how-heavy-is-a-tesla-battery/ Curb weight of the Model Y is also 4400 lbs, so having to tow a 2500 lb trailer would be a significant hassle. Perhaps that could be offset by making the trailer smart and adding motors to it that the main brain could control through the power link. If it could push its own weight and it had a 1.5x battery, and if it also had regenerative braking, then it could get close to doubling the distance. Then again, each trailer would cost right about the same as a full vehicle, and would require an entire factory to be spun up to make them, and it would be an incredibly valuable product and therefore ripe for theft. Lots of negatives, not a lot of positives. It would be better all in all to be able to hot swap the batteries then. With standardized batteries put onto an integrated sled system, a robot at the fuel pump could pull the discharged battery and put it on a battery tester/charger and insert a fresh charged battery in its place. I guess that would be more like an oil change or system flush, but the advantages would be manifold. Batteries wouldn't be the weak spot in the system any longer. The likelihood of people keeping batteries until they degraded would be significantly reduced, problematic batteries could be identified and repaired or recycled before they erupted, and assuming that the system was in wide usage it could enable road trippers to stay on the road longer quicker and waste less daylight. Plus, for manufacturers, fuel stations, and mechanics, it would be an opportunity to make more money off of vehicle owners while providing safer, longer lasting vehicles to customers. It's probably still a post-scarcity pipe dream though.
sowbug 3y ago
That's just a UI trick, isn't it? Make 5% display as 0%, and add a solemn-looking toggle switch to select the reserve battery. (According to a random source on the web, a Model Y battery weighs 1,770 pounds, so a perfectly efficient 5%-size physical battery would add another 88 pounds to the cargo.)
- berkes 3y ago
  My car has a spare tank built in. I just carry a spare- spare jerry-can because the indicator is just too unreliable and the milage on the built-in spare tank rather meh.
- noAnswer 3y ago
  > Make 5% display as 0% That is already how it is done on all EVs. malwrar should have kept driving. Playlist of tests. https://www.youtube.com/watch?v=OIi_8OXfLeg&list=PLqKx2qnB8Xv6ddxPVkiqQZMNyLtYjqQkq https://www.youtube.com/watch?v=OIi_8OXfLeg&list=PLqKx2qnB8X...
fwungy 3y ago
A Jackery 1000 is already 20+ lbs and over $1000, and it wouldn't get an EV far. Spare power packs would have to be large and very expensive. Better idea would be a mobile fast charging truck. Ironically that truck would have to be a diesel to make sure it had the range to support distant stranded vehicles, and not be insanely heavy and expensive itself.

by berkes 3y ago

pjc50 3y ago

You know, I don't think I've seen this idea before. I've seen discussion of "can we swap the whole battery pack at a station", "can we make the cells pourable", people carrying generators, etc., but I've not seen the idea of a removable part of power pack for limp-home situations. A modern equivalent of the Jerry can.

mlyle 3y ago

> I bring a spare 5L tank with petrol under the backseat always. Not too safe of an idea... > An EV could achieve the same with a small portable powerbank, not? Say that tank gets you 70km. You'd need 15 kilowatt-hours or 54 megajoules of battery, or about 56kg and about 25L of volume to do the same. > An EV could achieve the same with the back-seats replaced by additional battery-packs, not? I'd presume this might be too heavy or not allowed due to regulations, but technically just adding ridiculous amounts of batteries would solve this. Maybe, but it's also ridiculous amounts of money. Also, really increasing the mass of the vehicle is enough to hurt efficiency, so...

AlexandrB 3y ago
I would love to see some kind of standardized way of supplementing an electric car's battery. Most people don't need massive EV range all of the time, just when going on long trips. Being able to buy or rent an extra battery pack and throw it in the trunk, frunk, or back seats to add more range seems ideal for those cases.
- BizarroLand 3y ago
  I've thought it would be great if there were rentable battery trailers that had an extra full charge or two built in, plus maybe some extra storage. uHaul could make a killing off of them for people who want to take their EV on a road trip. If you could get 600 miles off of a single combined full charge you would be in the range of reasonable American road trip distance, and you could make the choice to stop and eat and occupy two chargers to get another 480 miles or so out of a 30 minute stop. I usually clock about 900-1100 miles a day when I'm doing a destination road trip, so I would still chafe at that limit, but it would beat the heck out of sub-300 mile limits between long breaks for me.
  - mlyle 3y ago
    Even with a smaller trailer, though, I'd expect a 33% or so range penalty-- it's just not too much of a win. You don't make it anywhere near twice as far.
    - BizarroLand 3y ago
      Even so, assuming there were a nationwide network of them, you could pull in, swap trailers, and be on your way in 15 minutes. Of course, this is in an ideal world where everything goes my way. I wonder if the penalty would be as high as 33%. Seems like it would be simple to make a maximally aerodynamic battery trailer since human comfort doesn't have to be considered. Then you're only adding the weight and drag of a few hundred lbs of trailer and battery. I would think the penalty would be in the high single digits or at most in the very low double digits which could be offset by having 1.5x or 2x normal battery capacity in the trailer. *Ninja edit, I decided to look this up. The Model Y's battery is 1700 lbs, so you are absolutely right that there would be a significant distance penalty adding that much weight to the vehicle plus the trailer weight and the battery armor as well if that isn't included in the weight. https://www.carparts.com/blog/how-heavy-is-a-tesla-battery/ https://www.carparts.com/blog/how-heavy-is-a-tesla-battery/ Curb weight of the Model Y is also 4400 lbs, so having to tow a 2500 lb trailer would be a significant hassle. Perhaps that could be offset by making the trailer smart and adding motors to it that the main brain could control through the power link. If it could push its own weight and it had a 1.5x battery, and if it also had regenerative braking, then it could get close to doubling the distance. Then again, each trailer would cost right about the same as a full vehicle, and would require an entire factory to be spun up to make them, and it would be an incredibly valuable product and therefore ripe for theft. Lots of negatives, not a lot of positives. It would be better all in all to be able to hot swap the batteries then. With standardized batteries put onto an integrated sled system, a robot at the fuel pump could pull the discharged battery and put it on a battery tester/charger and insert a fresh charged battery in its place. I guess that would be more like an oil change or system flush, but the advantages would be manifold. Batteries wouldn't be the weak spot in the system any longer. The likelihood of people keeping batteries until they degraded would be significantly reduced, problematic batteries could be identified and repaired or recycled before they erupted, and assuming that the system was in wide usage it could enable road trippers to stay on the road longer quicker and waste less daylight. Plus, for manufacturers, fuel stations, and mechanics, it would be an opportunity to make more money off of vehicle owners while providing safer, longer lasting vehicles to customers. It's probably still a post-scarcity pipe dream though.

sowbug 3y ago

That's just a UI trick, isn't it? Make 5% display as 0%, and add a solemn-looking toggle switch to select the reserve battery. (According to a random source on the web, a Model Y battery weighs 1,770 pounds, so a perfectly efficient 5%-size physical battery would add another 88 pounds to the cargo.)

berkes 3y ago
My car has a spare tank built in. I just carry a spare- spare jerry-can because the indicator is just too unreliable and the milage on the built-in spare tank rather meh.
noAnswer 3y ago
> Make 5% display as 0% That is already how it is done on all EVs. malwrar should have kept driving. Playlist of tests. https://www.youtube.com/watch?v=OIi_8OXfLeg&list=PLqKx2qnB8Xv6ddxPVkiqQZMNyLtYjqQkq https://www.youtube.com/watch?v=OIi_8OXfLeg&list=PLqKx2qnB8X...

fwungy 3y ago

A Jackery 1000 is already 20+ lbs and over $1000, and it wouldn't get an EV far. Spare power packs would have to be large and very expensive. Better idea would be a mobile fast charging truck. Ironically that truck would have to be a diesel to make sure it had the range to support distant stranded vehicles, and not be insanely heavy and expensive itself.