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Comment by usrusr | Hacker News Reader

Perhaps battery sized for a reasonably long joyride and nothing more? I'd say that's how you'd build a lightweight electric sports car.

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Yes, a small, fast charging lithium-carbon battery is how you build a lightweight scooter so why not a sports car:

https://www.mahle-powertrain.com/en/news-and-press/press-rel...

Or lithium-sulfur batteries for a battery pack that weighs less:

https://lyten.com/lyten-launches-lithium-sulfur-battery-plat...

Or just go for battery swaps:

https://www.gogoro.com/news/400k-gogoro-network-subscribers/

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.

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.

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.

You'll love this then: 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.

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.

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. :)

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.

That makes sense.

I keep wondering why we haven't seen an EV Miata, but you'd probably end up with a small, 4000lb car.

Lacking significant battery improvements, I'm thinking the electric F150 is going to be the game changer in all this.

Have you forgotten the original Tesla Roadster? The Miata occupies a very specific niche (there are other sports cars, but none with the same balance of affordability and performance and availability as the Mazda Miata), but there are quite a few EV sports cars. They're just not remotely humanly affordable.

Interestingly enough, the Roadster is based on a Lotus Elise, so we've come a full circle here..

A lot of people want electric Miatas. I think the main reasons they aren't being made is that Mazda would have to invest a lot of R&D into designing it and they're a relatively small car company that can't do everything and they're probably not convinced that they can make an EV that feels like a Miata.

The main issue is batteries. They could either make a light EV without much range, or make a long-range EV that's quite heavy. Placement's an issue too. If they put the batteries in back under the trunk, they'll have too much weight in the rear causing it to spin out on corners. If they put it under the middle of the car like in most modern EVs, it'll make the car taller and look very un-Miata like. Best case is probably to put most of the battery in the front where the engine was, but I suppose that might be a safety issue (it could be crushed in a collision).

I think an electric Miata will happen eventually, but probably not until Mazda can buy cells that are in the 250-300 watt hours per kg range.

(Personally I would love to see an EV Miata with a manual transmission, but that's probably not going to happen.)

https://news.ycombinator.com/item?id=28653942

I don’t understand why you’d buy an automatic miata, let alone an electric one. Is there even a market for this?

Because it fits other parameters of practicality. Gatekeeping what's a real sports car might fly on car enthusiast forums, but it just isn't a good look outside of them (it's not a good look there either, tbh).

Mazda sells a decent number of automatic Mazdas each year (24% of softtops, 48% of hardtops in 2018-2019 according to auto blog), so people are buying them. The reason to buy a hypothetical electric Miata? Same as for any sports car - it's faster than yours, or at least as fast I can afford.

Whether there's a market for them, I can't say, but if someone doesn't understand the existing market for an existing car, I'm extremely doubtful of their predictions about a hypothetical new car in that niche.

Miatas are completely impractical cars. Have you actually driven one?

Of course it comes down to personal taste, but I can’t understand why you’d buy a “fun car” but strip away all the things that make it fun. There are much better alternatives at that point.

I’d buy a small electric sports car because of the high acceleration. I drove manual transmissions all my life and, while it’s fun in a race course, it’s far less entertaining in traffic.

Gas-powered cars are annoying to drive in traffic because the engine has a minimum RPM. EVs don't have that, so in stop-and-go traffic you'd be able to just leave it in 2nd gear the whole time and never touch the clutch.

Technically there's no reason an EV Miata couldn't have a manual transmission, it's just that auto manufacturers so far have largely decided they'd rather just opt for a more powerful motor than deal with the drive train complexity, weight, and friction losses of a transmission.

I don't expect Mazda to make a manual transmission EV Miata but it's something they could do if they really wanted to.

I thought a valuable experience in driving a fun car would go missing when going to an electric. Not so. Driving a fast, well handling electric is pure joy to me.

Fine. We'll design a control system for EVs where you can feel that a fake clutch actually does something. We can supply speakers and a simulated tach to give the full sports car experience.

Really my own guess is that the manual trans will continue on the way out due to emissions law if nothing else (and lack of interest). Modern cars have little visceral interest in any case, probably better to buy a hemicuda with a stick or a Cobra kit.

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