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The Tesla Semi Is an Engineering Failure

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Re: The Tesla Semi Is an Engineering Failure

#21

Post by RobinL »

rgbrenner wrote: post #15

When I see insiders in the industry adopting new technology, while a commenter with no background in the tech says it's terrible.. I'll generally believe the industry experts. Tesla has presold hundreds of these trucks to walmart, fedex, etc. The question is what did he miss... Here's the first big mistake I think he made in the video at 3:45. He pulls this "1 to 20" number out of no where to come up with a battery w…

Thanks, I was curious about that. Key quote for others:

> [...] Tesla would need a 600 kWh to 1,000 kWh battery pack to produce the Semi’s 300-mile (483-km) and 500-mile (805-km) variants. Since a 600 kWh pack weighs about 8,000 pounds (3,629 kg), it would eat into payload as Class 8 trucks have a total weight capacity limit of 80,000 pounds (36,287 kg).

That would mean 6050kg for the 500 mile range. The video estimates it at 17t

Re: The Tesla Semi Is an Engineering Failure

#22

Post by l0k3ndr »

RobinL wrote: post #6

The video argues that, with current battery technology, to achieve the same range as a current semi, most of the weight of the truck will be batteries, leaving little weight for cargo (3 tonnes relative to 19 tonnes). I've noticed there is a common theme to arguments against electrification: that they assume it's necessary for an electric vehicle needs to match all the capabilities of a fossil fuel equivalent. i.e. t…

It can be used to transport battery while using it?

Re: The Tesla Semi Is an Engineering Failure

#23

Post by [deleted] »

rgbrenner wrote: post #15

When I see insiders in the industry adopting new technology, while a commenter with no background in the tech says it's terrible.. I'll generally believe the industry experts. Tesla has presold hundreds of these trucks to walmart, fedex, etc. The question is what did he miss... Here's the first big mistake I think he made in the video at 3:45. He pulls this "1 to 20" number out of no where to come up with a battery w…

[deleted]

Re: The Tesla Semi Is an Engineering Failure

#24

Post by twothamendment »

jimkleiber wrote: post #9
RobinL wrote: post #6

The video argues that, with current battery technology, to achieve the same range as a current semi, most of the weight of the truck will be batteries, leaving little weight for cargo (3 tonnes relative to 19 tonnes). I've noticed there is a common theme to arguments against electrification: that they assume it's necessary for an electric vehicle needs to match all the capabilities of a fossil fuel equivalent. i.e. t…

Or just swap out the batteries on the way. I think someone on here once suggested to do so at existing weigh stations in the US.

Swappable battery packs seem like a good idea. It might even be faster than waiting to pump 100 gallons of fuel.

I'm thinking existing truck stops would have a better chance of working than the weigh stations. let's leave the government it, they are barely competent at weighing a truck. Some trucks might not see a weigh station for a week. Some stations are nothing more than a pull out on the side of the road.

Re: The Tesla Semi Is an Engineering Failure

#25

Post by ErikVandeWater »

rgbrenner wrote: post #15

When I see insiders in the industry adopting new technology, while a commenter with no background in the tech says it's terrible.. I'll generally believe the industry experts. Tesla has presold hundreds of these trucks to walmart, fedex, etc. The question is what did he miss... Here's the first big mistake I think he made in the video at 3:45. He pulls this "1 to 20" number out of no where to come up with a battery w…

> But we know a 600kwh battery is 8000lbs.

From your own source it says 600kwh will only go 300 miles. Trucks are too big to use the existing supercharger network so a new one will have to be built for the truck to get any substantial distance.

> I'll generally go with the industry experts. Tesla has presold hundreds of these trucks to walmart, fedex, etc.

Do you have details on the terms of these deals? Dollars to donuts these companies can opt out without penalty. This is just a mutual marketing scheme between Tesla trying to seem like an industry leader and these companies trying to seem green.

Re: The Tesla Semi Is an Engineering Failure

#27

Post by ErikVandeWater »

collsni wrote: post #12

I understand the drivetrain weight argument, but this guy makes money off these negative viewpoints so.. now my YouTube feed is gonna be conspiracy theories.

> conspiracy theories

I get the feeling you use this phrase to dismiss anything you don't like. Nothing about this video at all describes or relates to a conspiracy.

Re: The Tesla Semi Is an Engineering Failure

#28

Post by nehalem »

fallingknife wrote: post #19

This video is bullshit. The 1:20 ratio for battery weight is nonsense. A Model 3 long range has a 1060 lb battery vs 20 gallons of gas which weighs 126 lbs. So it's more like 8.5x. Also he doesn't take into account the simplicity of an electric motor vs a ICE engine. e.g. an electric truck doesn't need a transmission, so there will be a lot of weight savings there.

It is also noteworthy that the video assumes that the truck would carry a battery equivalent of 1135 litres of diesel. But driving about 600 km a day at 30l/100km the truck only needs about 180 litres (140 kg) of diesel a day. Even with the 1:20 ratio, that would result in a 2.8 tonnes battery. Still punishing in terms of load capacity but much more realistic to offset through weight savings along the drive train.

Re: The Tesla Semi Is an Engineering Failure

#30

Post by mcguire »

Interesting. The problem described is the load capacity.

According to the video: The maximum capacity of a truck is 80,000 lbs or 36 metric tons. The average weight of a semi-tractor is 25,000 lbs or 11t, leaving 25t for fuel, trailer, and cargo. 300 gal of diesel at 7lbs/gal is 2100lbs or about 1t. A trailer is around 10t. That gives a cargo capacity of 14t. The difference between the Tesla and a typical semi is that the 1t of diesel is replaced by batteries, (according to the video) at a rate of 1lb to 20lb. As a result, the Tesla load capacity is small (or negative, according to my calcs here).

This is wrong.

I think the 1t of fuel is calculated as part of the 25t of semi tractor, rather than a separate weight. But that's a minor problem.

The big difference is that the range of a semi on 300g of diesel is about 1200 miles. The claimed range of the Tesla is a maximum of 500m. Therefore, the Tesla battery is comparable to 125g of diesel, or 875lbs, or about 1t. As a result, the Tesla should have about the same load capacity as a normal semi, just with 42% of the range.

On the other hand, that range is a problem. Truckers routinely complain about speed limits and limiters, because the difference between 55mph, say, and 70mph over a 10 hour (say) driving day is 150 miles. Drivers get paid by the mile, so that is some number of hundreds of dollars per day.

The Tesla's range of 500 miles per day (how long does it take to charge, compared to the driving hours schedule?) compared to the 600-700 miles per day of a typical semi is again some number of hundreds of dollars per day.

Does the Tesla have a hot-swappable battery pack? And how much does the Tesla tractor weigh? And why is this article flagged?

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