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Show HN: lapetitejort goes hiking, discovers perpetual motion
+3 miles hopefully didn’t include the energy spent going up, or the law of energy conservation would have been broken.
We have trains in chicago that reach whiskers up to charging lines above them. Same as the trolley systems in San Francisco. What if every major city to city freeway stretch had these in a lane for electric vehicles?
Seems like a lot of physical infrastructure spread out over a lot of area for little gain. Little gain because it doesn't feel like charging at fixed stations is so bad, and it's not something folks need to do that often. There's other challenges too. You'd also need to build some system for billing, such that people don't start to steal power. Do we trust the cars to meter themselves? Or do we try to have the line m…
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I think OP meant winding and not windy, but even if not, Teslas (and any other car) are designed to be aerodynamic, not the opposite, so it's quite impossible to yield more energy than it cost in that scenario, even ignoring motor efficiency, regenerative braking efficiency, and every other real world inefficiency.
Windy is a perfectly valid descriptive word for a twisting road.
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This scenario is a little different than a car but a Swiss company is experimenting with a Komatsu Dump Truck that basically recharges its battery using regen braking on it's trip down so it has enough power for the trip up. It actually generates a surplus of an extra 10kwh because the truck is carrying a full load down. https://phys.org/news/2017-09-e-dumper-world-largest-electri...
And going up it is empty. Its basically exploiting the fact that rocks at the top of a hill have higher potential energy than at the bottom. If you charged the trucks with wind/solar at peak times and used them to carry the rocks back uphill you could have yourself a very convoluted and mechanically fraught battery!
We have trains in chicago that reach whiskers up to charging lines above them. Same as the trolley systems in San Francisco. What if every major city to city freeway stretch had these in a lane for electric vehicles?
Are all the cars going to reach up 13 feet in the air to the charging lines? That would be a very tough sell. Not to mention the increased danger of live power lines coming down in an accident. Also, how would lane changing work? Do they have to decouple from one set of power lines and connect to another?
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Teslas will switch to friction brakes when regeneration limits (peak current or battery SOC) are exceeded. I’ve sustained constant 50kw regen while downhill through Appalachia passes, no issues, with the caveat that regen current is limited if the pack is cold until it approaches operating temperature (yellow dashed lines on the regen current display indicate your reduced regen capability).
I don't think the brake pedal was being used in this test, though.
The most spectacular example of regenerative braking are trains that are used in Scandinavia, heavily loaded with iron ore that is transported to the coast: "In Scandinavia the Kiruna to Narvik electrified railway carries iron ore on the steeply-graded route from the mines in Kiruna, in the north of Sweden, down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on th…
What if they had a Tesla merry-go-round where instead of charging your Tesla, you connected it to this giant horizontal ferris wheel that spun it around and charged the battery? It could be wind powered!
You said this as a joke, but I found myself (at least for a little while) wondering whether this might be more efficient than having the wind turbine generate electricity and then have that electricity power the charger. But then I remembered that there is the cost of moving the relatively heavy vehicle on the merry-go-round and realized it wouldn't actually work.
Even when your output is mechanical it's hard to beat electrical wires. But here the output is battery charge; no contest.
The most spectacular example of regenerative braking are trains that are used in Scandinavia, heavily loaded with iron ore that is transported to the coast: "In Scandinavia the Kiruna to Narvik electrified railway carries iron ore on the steeply-graded route from the mines in Kiruna, in the north of Sweden, down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on th…
The same as a quarry truck in Switzerland: https://www.autoblog.com/2019/08/26/edumper-electric-mining-...