3 ms·

I was under the impression that smaller batteries had a limit to peak power draw. Perhaps not important if you have an ultra-light vehicle and you’re not attemp

I was under the impression that smaller batteries had a limit to peak power draw. Perhaps not important if you have an ultra-light vehicle and you’re not attempting to build a competitor to the Plaid.

HPsquared 5y ago
That's in line with the Lotus philosophy of light weight. A lighter battery doesn't need as much superstructure (the rest of the car) and doesn't need as much raw power to accelerate itself around. Perhaps thermal management could be somewhat opened up to the driver with short "sprints" possible, to add some more driver involvement to the experience.
jagger27 5y ago
There must be a balance. The lighter the car, the more acceleration you get per watt. I’d be very happy with a light weight EV Miata that went 0 to 100km/h in under or around 4 seconds. Not Model S Plaid or high end 911 fast, but still by far the fastest production Miata.
- frosted-flakes 5y ago
  You'll love this then: https://youtu.be/VZws7kE3U5k https://youtu.be/VZws7kE3U5k (EV swapped Mazda Miata MX5). There's a full build series too by the company that made it. I think £20k was mentioned as the cost of the conversion kit if they were to sell one. 120 miles range.
  - ArchStanton 5y ago
    Cool, thanks. I'll check it out. I've mostly been keeping an eye out on the aircooled VW conversions (or that EV 1968 Mustang on youtube). It'll really get interesting when you see more from-scratch cars that don't have the ICE history built in. There are a lot of changes that could be made in design. If the government didn't love to get in your business so much, maybe there could be a world of street-legal EV karts.
    - fragmede 5y ago
      There are - golf carts. They don't have the same sex appeal as a sports car, but in the many communities in the US where those are considered street legal, they are flourishing! They usually don't have doors and have a low top speed, but make for great third or fourth cars. Their top speed is low and limited by the law, though the laws that I've seen only specify what the top speed (often 35mph) but not how long (or how quickly) it takes to get there. Many are still on lead-acid batteries (36V or 48V) but you didn't specify battery chemistry. :)
elihu 5y ago
It depends on the batteries. It's true that larger packs generally draw less current per cell; whether you can get away with a small pack depends on whether the cells are designed to handle high discharge rates without damage. Tesla's approach seems to be to optimize their cells for energy density rather than power density. They can do that because the packs they use are huge. On the other hand you have relatively small batteries that go in hybrids that are optimized for power density.

HPsquared 5y ago

That's in line with the Lotus philosophy of light weight. A lighter battery doesn't need as much superstructure (the rest of the car) and doesn't need as much raw power to accelerate itself around. Perhaps thermal management could be somewhat opened up to the driver with short "sprints" possible, to add some more driver involvement to the experience.

jagger27 5y ago

There must be a balance. The lighter the car, the more acceleration you get per watt. I’d be very happy with a light weight EV Miata that went 0 to 100km/h in under or around 4 seconds. Not Model S Plaid or high end 911 fast, but still by far the fastest production Miata.

frosted-flakes 5y ago
You'll love this then: https://youtu.be/VZws7kE3U5k https://youtu.be/VZws7kE3U5k (EV swapped Mazda Miata MX5). There's a full build series too by the company that made it. I think £20k was mentioned as the cost of the conversion kit if they were to sell one. 120 miles range.
- ArchStanton 5y ago
  Cool, thanks. I'll check it out. I've mostly been keeping an eye out on the aircooled VW conversions (or that EV 1968 Mustang on youtube). It'll really get interesting when you see more from-scratch cars that don't have the ICE history built in. There are a lot of changes that could be made in design. If the government didn't love to get in your business so much, maybe there could be a world of street-legal EV karts.
  - fragmede 5y ago
    There are - golf carts. They don't have the same sex appeal as a sports car, but in the many communities in the US where those are considered street legal, they are flourishing! They usually don't have doors and have a low top speed, but make for great third or fourth cars. Their top speed is low and limited by the law, though the laws that I've seen only specify what the top speed (often 35mph) but not how long (or how quickly) it takes to get there. Many are still on lead-acid batteries (36V or 48V) but you didn't specify battery chemistry. :)

elihu 5y ago

It depends on the batteries. It's true that larger packs generally draw less current per cell; whether you can get away with a small pack depends on whether the cells are designed to handle high discharge rates without damage. Tesla's approach seems to be to optimize their cells for energy density rather than power density. They can do that because the packs they use are huge. On the other hand you have relatively small batteries that go in hybrids that are optimized for power density.