91–100 of 231 posts
BMW also makes rare-earths-free motors for their EVs and - at this very moment - theirs are far more advanced. They offer almost twice the power (up to 300kW vs 160kW) and are on a 800v architecture.
The cheapest EV model Renault sells is around €20K, the cheapest BMW EV is around €65K. It's safe to say the companies are not in the market bracket, no?
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It's more than that though. Any repairs due to wear and tear or whatever, ends up being really expensive. Although you can probably reduce the costs a bit if you get the non-branded OEM part or potentially the same part from another manufacturer (e.g. the toyota supra uses a lot of bmw parts so if the toyota part might be cheaper than the same bmw part).
That was my whole point actually, the wear and tear is really minimal if you get regular oil changes. Things don’t just break and need replacing. Tires, rotors, brakes, those wear out. The tires are not cheap, rotors and pads aren’t crazy expensive and super easy to DIY. What other wear and tear things are expensive?
Recently, there was a problem with the engine misfiring but it was $200.
LA, California
A historical pioneer in the complex technology of electric motors without magnets Those who know the history of electric machines will find the title and verbiage very amusing. Motors with no permanent magnets were the first practical ones, and at this point wound-rotor motors are over a century old. It's worth noting that some of the biggest motors have always been designed this way, because the size of magnets requ…
All big generators have an exciter coil that is used to generate the magnetic field. It has the advantage of allowing voltage regulation through adjustment of the field, rather than after the fact, which would be far less efficient.
In both motors and generators, there is an efficiency hit related to the need to supply power in order to generate the field, but when you scale up the system, it actually becomes more efficient to use the electromagnet. With the rare-earth mineral shortage, it makes even more sense.
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Could be wrong, but AFAIK the CATL Sodium batteries haven't yet hit LFP pricing. You are unlikely to see a vehicle with sodium batteries until after that happens, and it needs to be significantly less than LFPs as you Na batteries have more weight per Wh. I believe they also have a shorter lifespan (but not NMC short). Edit correction, looks like CATL is promising 15000 cycles, which is much longer than LFPs which us…
The energy density of LFP batteries are also 30-50% higher than sodium based battery chemistries. Even if sodium battery prices drop, the lower energy density is a big disadvantage. My understanding is that sodium batteries are aimed at stationary use-cases, like battery buffers for fast charging.
CATL already put sodium ion in cheap cars. And there are other benefits to this type of battery like a wider range of operating temperatures that cover essentially all of the extreme temperatures you'd find in the arctic and the hottest deserts.
I would not be surprised to find some of these batteries in big semis a few years down the line when the cost benefits make the space/weight sacrifices worth the trade off.
But you are right that domestic and grid storage are also going to be huge use cases.
let me guess.. but its 2x the price?
no, but requires introduces brushes (slip-rings really) which is a wear item
Also, compare this to ICE engines which experience continuous explosions, lots of mechanical parts, extreme temperature swings, etc. and still manage pretty decent durability. There's simply no base for assuming that parts like this wearing out and needing to be replaced is going to be a common thing.
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What advantage do permanent magnets provide that it isn't the case that all motors are made without them?
A lack of wear components. A permanent magnet motor uses permanent magnets on the rotor, but an electrically excited synchronous motor has an electromagnet on the rotor. This requires a rotating electrical contact which has normally been made with slip rings and carbon brushes. These wear over time and need replacement. Most large electric generators are externally excited synchronous generators using carbon slip rin…
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Long ago, when I was in Cub Scouts, one of the projects was to build an electric motor. The parts list was: 1. a plank to form the base 2. several 6 inch nails 3. wire 4. a tin can (as a source of sheet metal) 5. tape No magnets. But it worked perfectly fine when connected to a dry cell. Adventurous science lad that I was, I decided it would work better when connected to AC. So I attached a power cord and plugged it…
Been there. Im gonna guess that 90% of HN folk have similar stories to tell.
Mine was a bit fragile, and the first gust of wind shredded the sticks and plastic film.
But it was still fun!
As a teen I built a flame thrower. No, I'm not going to explain how to build one. My dad told me that God looks out for little boys, because otherwise they'd never survive to adulthood.
When I was 9, I found a book of his "Rocket Manual for Amateurs". The opening sentence was something like "if you're fascinated by things that burn and explode, this book is not for you." Who could resist a teaser like that? I promptly read it cover to cover. He wouldn't let me buy any of the necessary materials.
Kind of interesting for a professionally branded company to use "..." like that
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The cheapest EV model Renault sells is around €20K, the cheapest BMW EV is around €65K. It's safe to say the companies are not in the market bracket, no?
The bit the gets me more than the sale price is servicing. BMWs have a terrible record for needing expensive repairs. I know you shouldn’t rely on anecdote, but it seems I do.
> BMWs have a terrible record for needing expensive repairs.
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no, but requires introduces brushes (slip-rings really) which is a wear item
I don't think car owners have to worry about this the first half million miles or so with these motors. Electrical motors last a long time. We'll know for sure in a few decades, I guess. That's how long it will take for a significant number of their cars to actually drive that far. Also, compare this to ICE engines which experience continuous explosions, lots of mechanical parts, extreme temperature swings, etc. and…