5 ms·

> This could actually REDUCE refill times (if the swap out is efficient enough) Have you ever watched Formula 1 or NASCAR? They can fill 20 gallons of fuel in

> This could actually REDUCE refill times (if the swap out is efficient enough) Have you ever watched Formula 1 or NASCAR? They can fill 20 gallons of fuel in ~10 seconds. Do you really think a battery swap system could even come close to competing with that?

ubercore 10y ago
Just did some googling, and _including_ exit and entry through pit lanes, fastest refuel is 51.3s. I think a battery swap would be reeeeeally tough to accomplish. And most cars refuel every 14 laps, and races are about 384 laps. Totals over 5000km in 24hrs. That's a lot of batteries...
- mdorazio 10y ago
  Just for comparison, your numbers come out to one refill every 52 minutes. If we assume that charging a battery takes about an hour and a half (pretty reasonable based on current charge times for an 85 kWh battery), you really only need 3 batteries total. The battery swap that Tesla originally demoed was done in 90 seconds, and that was obviously for a low-speed, consumer-friendly environment. I don't see why you couldn't do a battery swap in 60 seconds if that was an engineering priority. I still think this is a pipe dream with current battery tech for other reasons (weight, power density, overheating, etc.), but from a logistics standpoint it might actually be possible.
  - ubercore 10y ago
    Can an 85kWh battery do 190km at race speeds? Le Mans records are 140mph (225km/h) avg speed and 253mph (407km/h) top speed. EDIT: thanks for noticing, added metric equivs. The difference was just in the sources I found reporting the units differently.
    - darklajid 10y ago
      This is confusing: Why is the distance in km, but the speed in miles per hour?
    - mdorazio 10y ago
      No, hence the last part of my comment. I was referring purely to logistics, not to practicality for winning the race.
detaro 10y ago
Just moving the mass in and out seems doable with proper design and gear (some kind of hydraulic lift?), but can you find a competitive car design where the battery is mounted properly (low and central) and still allows good enough access? Operator safety is of course an issue as well, you really would not want some power switch to fail.
- justin66 10y ago
  Before they installed some additional armor to the bottom of the Model S to increase crash safety in the event the car goes over something dangerous sticking up in the road, the Model S actually possessed the ability to do a quick battery swap by dropping the battery. There's a video out there with Elon Musk demonstrating the functionality. It never took off, I guess because the infrastructure never existed, and because of the aforementioned armor issues. It's too bad. I always thought battery swaps would be an ideal way to deal with the aging of these batteries. Depreciate the value of the battery based on some formula and allow people to get a newer one once their battery passes some usage threshold, seamlessly, and bill them for the upgrade.
toss1 10y ago
Good question. I'd say it is probably possible to replace a battery pack on the gasoline-refill time scale with a well-engineered drive-over clip-in type mechanism or a side-trolley replacement mechanism. They replace whole nose assemblies in <30sec in F1. Audi some years ago replaced the entire rear transaxle & suspension assembly at LeMans in < 5 minutes in the middle of the night, because they'd anticipated the potential need for it and done the prior engineering necessary (iirc, that car finished 2nd and their other one won). Reliability and safety would take some real work, just like the high-speed fuel rigs previously used in F1.
iamgopal 10y ago
With proper engineering, 10 second is enough to change the Battery. It's like VMC tool changer.

ubercore 10y ago

Just did some googling, and _including_ exit and entry through pit lanes, fastest refuel is 51.3s. I think a battery swap would be reeeeeally tough to accomplish. And most cars refuel every 14 laps, and races are about 384 laps. Totals over 5000km in 24hrs. That's a lot of batteries...

mdorazio 10y ago
Just for comparison, your numbers come out to one refill every 52 minutes. If we assume that charging a battery takes about an hour and a half (pretty reasonable based on current charge times for an 85 kWh battery), you really only need 3 batteries total. The battery swap that Tesla originally demoed was done in 90 seconds, and that was obviously for a low-speed, consumer-friendly environment. I don't see why you couldn't do a battery swap in 60 seconds if that was an engineering priority. I still think this is a pipe dream with current battery tech for other reasons (weight, power density, overheating, etc.), but from a logistics standpoint it might actually be possible.
- ubercore 10y ago
  Can an 85kWh battery do 190km at race speeds? Le Mans records are 140mph (225km/h) avg speed and 253mph (407km/h) top speed. EDIT: thanks for noticing, added metric equivs. The difference was just in the sources I found reporting the units differently.
  - darklajid 10y ago
    This is confusing: Why is the distance in km, but the speed in miles per hour?
  - mdorazio 10y ago
    No, hence the last part of my comment. I was referring purely to logistics, not to practicality for winning the race.

detaro 10y ago

Just moving the mass in and out seems doable with proper design and gear (some kind of hydraulic lift?), but can you find a competitive car design where the battery is mounted properly (low and central) and still allows good enough access? Operator safety is of course an issue as well, you really would not want some power switch to fail.

justin66 10y ago
Before they installed some additional armor to the bottom of the Model S to increase crash safety in the event the car goes over something dangerous sticking up in the road, the Model S actually possessed the ability to do a quick battery swap by dropping the battery. There's a video out there with Elon Musk demonstrating the functionality. It never took off, I guess because the infrastructure never existed, and because of the aforementioned armor issues. It's too bad. I always thought battery swaps would be an ideal way to deal with the aging of these batteries. Depreciate the value of the battery based on some formula and allow people to get a newer one once their battery passes some usage threshold, seamlessly, and bill them for the upgrade.

toss1 10y ago

Good question. I'd say it is probably possible to replace a battery pack on the gasoline-refill time scale with a well-engineered drive-over clip-in type mechanism or a side-trolley replacement mechanism. They replace whole nose assemblies in <30sec in F1. Audi some years ago replaced the entire rear transaxle & suspension assembly at LeMans in < 5 minutes in the middle of the night, because they'd anticipated the potential need for it and done the prior engineering necessary (iirc, that car finished 2nd and their other one won). Reliability and safety would take some real work, just like the high-speed fuel rigs previously used in F1.

iamgopal 10y ago

With proper engineering, 10 second is enough to change the Battery. It's like VMC tool changer.