Number 1 problem is battery weight though. Not electric motors.

I have a 84 w123 300D, and would love to add some more power to it. Lightweight hub motors would be great, but any decent size battery would be at least 200lbs+, which is hard to do on a old chasy.

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dotancohen a few seconds ago | parent | next [-]

Reducing the motor mass by 200 kg means you've just removed 10% of the weight of the vehicle. You could theoretically now reduce the battery pack by 10% as well.

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tonyarkles 2 hours ago | parent | prev | next [-]

Something to keep in mind with hub motors is that they’re unsprung weight, vs the battery pack is pretty much always sprung. While that’s not a huge differentiator for efficiency, it sure cuts down on the abuse the wheels and hub motors will experience

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serf 3 hours ago | parent | prev | next [-]

its less hard than you'd think unless you're really going for long range.

for my sailboat I am getting rid of a 300lbs diesel and a 30gallon fuel tank with a 45lbs PMAC.

That means I have opened up about 465lbs for batteries.

Now, with a sailboat you're never truly out of range -- but the point stands : these things are so much lighter than ICEs on average that there is a lot of opportunity even with battery weight as it is (and it's getting better daily).

	▲	lazide 2 hours ago \| parent [-]
		Uh, car batteries are much heavier than most ICE’s. The curb weight on teslas’s are crazy high. BYD can be lighter because they skip on safety gear and proper structural elements - in my experience.

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WillAdams 2 hours ago | parent | prev | next [-]

Jeep/Stellantis certainly had problems trying to do this:

https://www.thedrive.com/news/jeep-tells-4xe-hybrid-owners-t...

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parpfish 3 hours ago | parent | prev | next [-]

i know series hybrids aren't as efficient as parallel hybrids (thanks technology connections!), but i wonder if they'd be a good candidate for fun restomods.

drop in a tiny, powerful electric motor and a small battery (crammed in whatever location is best for weight distribution), and then wire up a little genny powered off your existing fuel tank that can jump in as a range extender

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tclancy 3 hours ago | parent | prev | next [-]

Yeah, my comment was hand-waving away a bit of the reality of it, but swap the Fiero engine for a battery and some of these and it's got to be close to achieving full lift.

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j_maffe 3 hours ago | parent | prev [-]

I think the cited weight loss comes from energy efficiency gains leading to less battery capacity needed.

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FabHK 3 hours ago | parent | next [-]

Electric engines are already very efficient (particularly compared to internal combustion). If you go from 90% to 95% efficiency, you don't save much in terms of battery.

ETA: Internal combustion engines half a century ago had an efficiency of 20%, now they're at 40%. That cuts the fuel you need to carry in half. Electric engines are near 100%, and as I said, going from 90% to 95% efficiency cuts required battery by a bit more than 5%, so peanuts.

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ajuc 2 hours ago | parent [-]

Going from 90% to 95% efficiency you're halving the thermal loses, thus reducing the need for cooling by half. It's a big deal.

Same with going from 99% to 99.5% efficiency. It still reduces the cooling needed by half.

	▲	testdelacc1 2 hours ago \| parent [-]
		> reducing the need for cooling by half But the motor is not the only thing that needs to be cooled. It’s mainly the battery, which has a narrow operating range. The power electronics that convert AC to DC also need to be cooled. So you’re halving the cooling needs of the motor, which is nice but small compared to the other two. And even then, total cooling doesn’t impact range that much compared to warming the battery in cold climates. I think you’ve overstated your case.

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HDThoreaun 3 hours ago | parent | prev [-]

In the video the yasa guy said most of the weight loss is from getting rid of the yoke.