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Tesla Semi

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Re: Tesla Semi

#371

Earlier quoted context omitted.

Yeah that is just classic "what sounds really impressive but actually isn't that bad" marketing nonsense. It might be able to withstand an atomic glass but it's still going to crack if a big enough stone his it at 70mph.

Big enough, yes, but there was footage of hitting it with a pretty big hammer.

I've tried smashing a windscreen with a hammer. The first few blows didn't do anything at all. All windscreens are very strong.

Re: Tesla Semi

#372
post #281

Earlier quoted context omitted.

If you check out the reveal, you'll see that it doesn't have those ridiculous covers, nor does it have near zero clearance between the cab and trailer which would prevent articulation, and nor does it have near zero ground clearance.

> If you check out the reveal, you'll see that it doesn't have those rediculous covers https://tctechcrunch2011.files.wordpress.com/2017/11/tesla-s... ? I'm not sure what you mean. Looks about the same as the linked page to me. > nor does it have near zero clearance between the cab and trailer which would prevent articulation, and nor does it have near zero ground clearance. https://i.imgur.com/cECtzId.png https://i.…

> If you check out the reveal, you'll see that it doesn't have those rediculous covers

In the reveal the first truck does have the covers over the wheels, the second one doesn't. Check the livestream at about 3:00 [0]

[0]: https://livestream.tesla.com/

Re: Tesla Semi

#373
Anyone else find it odd they don't talk about the battery?

500 miles of range at 2kwh a mile is a 1000kwh battery which is 10 model S batteries.

Model S battery weighs 1,200 lbs lets assume they somehow improved on that by 20-30% so this is a 10,000 lb battery. Not sure how much the motors weigh, the Tesla motor and inverter are about 350lbs so lets say another 1000lbs.

A Diesel engine, transmission and fuel for 500 miles is about 5,000 lbs.

So I guess they made up 6,000 lbs in lightwieght materials? Or does it have less carry capacity since the trucks can't weigh more than 80k total?

Then there is the cost of the battery. Tesla is currently saying thier cost are below $190/kwh. At $180 that battery is $180,000 dollars cost! They must be counting on the Gigafactory getting it down to $100 kwh, still $100k cost just for the battery. The battery cost is as much as a new Semi's price.

The Megacharger is 400 miles in 30 minutes, that would be a 1.6 megawatt charger. They have to be built out across the country.

I am pretty impressed, I honestly didn't think they would do a megawatt battery. 500 miles is what you need minimum for "long haul" or a solid days driving even though most diesel semis have 1000 mile+ ranges.

Just not sure how the economics work out, but I hope it does.

Re: Tesla Semi

#376

Ok as a mechanic a few million questions: * What happens when a wheel seal goes? Do I have to remove all that ridiculous plastic on #2,3 axels?? * What happens when a tire blows? Is it going to destroy all that plastic and take out a few more tires in the process? * Why all the glass? I've spend entire days replacing windshields for a 12 or so truck shop which generally come in two (drivers and passengers), the Tesla…

Well, the glass is "thermonuclear explosionproof," whatever that's supposed to mean. They are claiming it will never need replacing. Musk did dwell on that for quite a while in his talk.

Re: Tesla Semi

#377

Ok as a mechanic a few million questions: * What happens when a wheel seal goes? Do I have to remove all that ridiculous plastic on #2,3 axels?? * What happens when a tire blows? Is it going to destroy all that plastic and take out a few more tires in the process? * Why all the glass? I've spend entire days replacing windshields for a 12 or so truck shop which generally come in two (drivers and passengers), the Tesla…

The windshield is a lot more like a modern Class A RV windshield. You don't necessarily need a crane to replace, just a couple guys.

Having some tough glass though as they promoted would be really nice on an RV, I'm jealous.

Re: Tesla Semi

#378
post #296

Earlier quoted context omitted.

I took an interest in this and looked up "retarder" on Wikipedia and it mentions engine braking (and exhaust braking), hydraulic retarders and electric retarders which are eddy current brakes more commonly used in the railways. Which one are you referring to? According to the article, most commonly these are not used for regenerative braking, the energy is wasted as heat instead. Eddy current brakes can be used for r…

Sorry, for not checking Wikipedia. Because I work in the industry as an electrical engineer defining standards, and owning a historic truck myself just for fun, because I can. Originally, it is right that retarders were introduced to just having a non-destructive brake by just wasting the energy. That was around the 1980s. This was just to save maintenance cost as brakes were a big part of that costs. The trucking in…

My 2013 Mitsubishi Outlander Sport has regenerative braking. Seems to work ok but I'm not sure how much it actually helps.

Re: Tesla Semi

#379

Earlier quoted context omitted.

He states that they have spent a lot of time talking to truckers and truck companies. I would guess they believe that with an electric drive train repairs and maintenance will be an order of magnitude lower (not sure how that works for tires and wheels). Body damage should also be much lower with automatic breaking and other features of enhanced autopilot. As Musk said, broken glass is a big cost for trucking as you…

I wonder about accidents. Will the driver be trapped, because the glass cannot be broken?

Firefighter here. I wouldn't be especially worried about the glass. Hitting it with a hammer isn't all that impressive (take a hammer to your driver's side window... I bet you'll be surprised how ineffective it is).

Re: Tesla Semi

#380

Anyone else find it odd they don't talk about the battery? 500 miles of range at 2kwh a mile is a 1000kwh battery which is 10 model S batteries. Model S battery weighs 1,200 lbs lets assume they somehow improved on that by 20-30% so this is a 10,000 lb battery. Not sure how much the motors weigh, the Tesla motor and inverter are about 350lbs so lets say another 1000lbs. A Diesel engine, transmission and fuel for 500…

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