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Comment by Robotbeat | Hacker News Reader

Tesla already uses aluminum for power cabling because it’s cheap and lighter weight. Tesla Model S were induction motors (at first at least) with no rare earths, and Tesla is partnering with CATL for lithium iron phosphate batteries in lower cost versions of, if I believe, Model 3 and Y.

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I thought CATL makes lithium iron phosphate batteries, and lithium sulfur hasn't been commercialized yet. Unless there's some news on that front I missed?

I think induction motors tend to be less efficient than permanent magnet motors (and thus require more cooling). The Netgain Hyper9 (a popular motor for conversions) is a permanent magnet motor which doesn't use rare earths. It's very efficient but not particularly powerful (though that may be due more to the relatively low voltage it runs at).

That's cool that Tesla is using aluminum for power cables. Makes sense to save cost and weight where you can.

Yes, I meant iron phosphate. (I’ve had sulfur on my mind from Bye Aerospace’s 925km range 8-seat electric aircraft, working with Oxis Energy.)

Note to replace copper wiring with aluminum, you have to go up at least one gauge size.

Yeah, aluminum is a worse conductor so you need thicker cable. It's less dense, though, so I think it usually comes out as being lighter. Thicker cables can be more inconvenient. I think aluminum also tends to have more problems with oxidation causing too much resistance at electrical contacts.

I think for motors generally you just end up with a larger motor for the same amount of power.

All points you make are very true. In addition, aluminum tends to crack as it ages and you'll find aluminum wiring is usually a culprit in electrical fires. In the world of mobile electronics, it's usually looked down upon as the cheapest alternative when compared to real copper conductor used in higher quality automotive wiring.

It only requires proper engineering of the connection. Aluminum itself doesn’t crack in properly engineered joints. What fails in old houses is shoddy connections.

If people look down upon it, it’s because they’re either lazy or ambivalent. It’s the superior performance solution in some situations.

Or raise the voltage at the same time you change from Cu to Al.

"Tesla already uses aluminum for power cabling because it’s cheap and lighter weight."

Ugh, really ? That offends my sensibilities ...

Why? A properly engineered aluminum power cable is superior to a copper one when weight is at a premium.

Aluminum is less ductile and prone to galvanic corrosion. It can definitely be engineered to work properly, but copper is much more forgiving.

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