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How hard would it be to make an electric semi truck
- Thread starter AMPd
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We are talking 2 to 5 years from now. Panel efficiency should be much better same goes for battery tech. You can also have panels on the side (1 or 2 ft from the top). So use 12ft wide, 20 Watts per sq feet and 8 hours of sun in your calculations and you're at 100kWh. Keep in mind that other battery chemistries could be considered for a truck that are not practical for a car (ex : Al-Air). This would allow a mix if Al-Air and Li in the same vehicule for which Tesla already filed a patent a long time ago...
As for the truck vs trains comparison, trucks are much more versatile. You don't need to plan days in advance, deal with timetables, rights of passage agreements, regulations and etc. Not to mention that depending on where you go, there is no guarantee that the electricity would be coming from a clean source.
In other words, the Tesla Truck would be just like a train but without the complications and with the capability to deliver directly to the required destination, not just a station.
In other words, the Tesla Truck would be just like a train but without the complications and with the capability to deliver directly to the required destination, not just a station.
JRP3
Hyperactive Member
Panel efficiency could double, (it won't), and it still wouldn't be enough to do what you claim. Battery improvements have nothing to do with how much energy can be captured by solar panels.
Side panels would basically be useless because of sun angle, so no.
Again, irrelevant for capturing solar power. I'm not saying battery tech doesn't allow for an EV truck, I'm simply saying your idea of solar panels on the truck providing anywhere near 50% of energy needs is quite far from reality.
I did my analysis very quickly using quick google searches. Definitely would be best to use whatever is the best pack available.
From a cost standpoint, Tesla is making roughly 100k packs a year, using a standard pack in its aluminum housing prevents the need to do any new engineering. This isn't to say Tesla couldn't easily create a lighter better semi form factor I just don't have knowledge either way. And I do know they want to automate and use robots for everything.
Are you sure Tesla uses electric trains for shipping?
These are very valid points. But 40 trucks (from my example) traveling from Reno to Fremont adds little to the million+ cars on this route daily. I see it more as an excellent way to advertise. Seeing massive electric Tesla trucks (with no nasty carbon emissions) on this route would be extremely impressive to the million+ cars on this route daily.
Its 236 miles from Fremont to Reno. And my semi with only removing the ice bits has a 268kw battery. Though you're probably right 1k wh/mi would be a minimum.
brucet999
Active Member
Use your imagination. A 3500 lb 5-passenger car manages to carry about 900 lb of cargo (passengers and luggage) about 25 miles on one gallon of gasoline. Vehicle weight to cargo ratio = 3.9 : 1
A 4500 lb Tesla carries the same load the same distance on about 10 kWh of power, using a 1200lb 85 kWh battery. Vehicle weight to cargo ratio = 5 : 1
A loaded truck & trailer weighs about 80,000 lb and carries a 40,000 lb payload 25 miles on about 4 gallons of diesel. Vehicle weight to cargo ratio = 1 : 1
How big would that electric truck's battery have to be to deliver enough power? Bear in mind that the legal weight limit per axle is 12,500 lb, so battery weight has to displace cargo weight (so does fuel in a diesel, but 250 miles worth of diesel weighs just 264 lb. on a vehicle 16 times as heavy as Model S.
@JRP3 : my point regarding the battery chemistry is that with all the R&D going on, we might need a lot less energy to recharge a battery in the future whether it's made of Li or Al-air. Therefore what you consider useless in terms of panels now might be sufficient 2 to 5 years from now...
This said, I agree with you that even in my wildest dreams, the chances of a truck arriving at destination with 50% battery is highly unlikely but if we just assume that the panels efficiency doubles, you have 50kWh per day which is enough to recharge your 268kWh semi in 5ish days for free. It might also provide a nice 25-50kWh buffer to ensure you cover those 236mi from Fremont to Reno
This said, I agree with you that even in my wildest dreams, the chances of a truck arriving at destination with 50% battery is highly unlikely but if we just assume that the panels efficiency doubles, you have 50kWh per day which is enough to recharge your 268kWh semi in 5ish days for free. It might also provide a nice 25-50kWh buffer to ensure you cover those 236mi from Fremont to Reno
JRP3
Hyperactive Member
That can't happen. You'll need the same energy to charge a 268kWh pack in the future as you need today, 268kWh, (plus charger losses). Lithium chemistry charges around 95-99%, so there are no significant gains to be had. Plus your 268kWh pack is probably much too small. Semis can travel 500-1000 miles on a tank, so to hit the low end of that you'd need a 500kWh pack.
The 268kwh pack was just a result of my napkin math of removing some ice components and adding electric components to keep the exact same weight of the original truck.
It also was only for the specific purpose of Tesla transport of battery packs from Reno to Fremont and not as a commercial product.
Equip them with Tesla autopilot hardware and software to begin gathering data on one specific route to and from Reno and Fremont.
I'm sure it is 1000 times easier to develop fully autonomous driving on one specific route than something that can drive anywhere. While the technology (both hardware and software) advances they will already have loads of supervised data on this one specific route. And it makes sense that regulators would be far more willing to give Tesla approval on an autonomous vehicle that stays in house and drives one route before they would allow them to be sold to anyone/everyone to go anywhere/everywhere. The market buzz from Tesla having fully electric autonomous trucking powered by gigafactory solar would be incredible.
Now as to a commercial product, if you need 500kwhr than you only need 240 more kwhr than my example. That's less than 3 more packs or 3600 lbs. If a semi can carry 40,000 lbs you lose less than 10% load capacity, but you're still driving something that doesn't burn petrol. Then again, my idea was for 40 semis for in house use only. Tesla could use this experience to build commercial semis down the road if they wanted too.
Somewhat tangent, and train vs truck aside, one massive benefit of automated trucks is that they can use roadways at off peak times.
TaoJones
Beyond Driven
Not quite a truck, but there's this:
12 miles closer to doing their part...
Mercedes' autonomous bus makes a landmark trip on public roads
12 miles closer to doing their part...
Mercedes' autonomous bus makes a landmark trip on public roads
Oh yeah!!! Now just waiting to see if they'll have solar panels as a bonus. Btw, forgot to memtion that the side panels will unfold à la ModelX when the semi is parked to capture more sun. Should allow to get 100Kw+ per day (3x area coverage * 2x efficiency). I have even more ideas for that truck now but will keep some secrets as well...
Can't wait to see the prototype!!
Running some rough and dirty math, that would give you a range around 53 miles for a fully loaded 80,000 pound truck. I base this off a 4800 curb weight Model S 90 which gets 294 EPA range. 4800/80000 gives you 0.06 (weight of Model S vs wight of a truck). .06 * 294 (range of a 90D) gives you 17.64 miles of range if you stuck the 90's battery in a semi truck. Multiply that by three as you suggested and you get 52.92 miles of range. Perhaps you get some slightly better efficiency from a tri-motor setup, but that will be erased by a loss in aerodynamic efficiency.
Obviously that will never cut it. You need at least a 900 kw pack to get 530 miles of range, which would likely be the minimum needed by the industry. More likely, you would see 100kw in the cap and another mw in the trailer totalling 1.1mw. That would give you 647 miles of range. That is still well under the total range of a full tank of diesel on a modern semi.
And no, solar panels don't even put a dent in the amount of energy needed.
I don't think that the math works exactly like you wrote it. And my physics is pretty rusty, so it would take me a while to try to calculate all the forces, so no thanks. But I do know my physics is good enough to say you can't just take the weight difference and extrapolate that out to try to say you need x more packs, in a frictionless world, yes, but in our world of friction, NO.
A loaded semi weighs roughly 16 times a model s. It does not have to have 16x the coefficient of drag and hence wind resistance. Wind resistance is the largest force that needs to be overcome here. And I know for a fact that a semi won't have 16 times the wind resistance. Just guessing, it would need to be about 50 feet tall for this to be true.
Edit: not exactly sure how the rolling resistance increases, maybe 16 times, maybe more, maybe less but it doesn't have 2 axles it has 8. Anyways I do know, it will require loads more energy, but your extrapolation is just incorrect.
Further edit: My example semi was designed as showing that just substituting ICE bits with electric bits you end up with a semi with more torque more hp and a little over 3 1200lb Tesla battery packs.
Also I mentioned that Tesla could build the first prototype autonomous Semis specifically for in house shipping packs from Reno to Fremont. This would allow them to plug in the 40 or so packs (about 40,000 lbs of cargo) in parallel to power the trip from Reno to Fremont. This also would allow them to do extensive road testing of their motors under high torque demand, like needed for industrial applications.
It would also allow them to get regulatory approval for a very specific autonomous route (aka- Reno to Fremont) before its given to the masses.
I see this as a huge catalyst for Tesla:
1. Having Tesla Semi's on the road for their own corporate use. There would be a lot of exposure for the Tesla branded truck traveling on the highly traveled hwy 80. And, with that happening how many other companies would want to order the same thing.
2. The media buzz of Tesla trucks 100% powered from solar at the gigafactory.
3. The first commercial autonomous transport.
4. It would make it obvious to a lot of people on the fence that electric transportation is clearly the future for ALL use cases.
5. How much nicer it would be to follow behind a semi that's not spewing poison.
6. Drafting!!!!!!! Like I said, Tesla would need about 40 semi's to transport all the required packs from Reno to Fremont.
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ratsbew
Active Member
I'm totally in love with the idea of a Tesla EV semi truck. I think it makes sense on so many levels. Yes, the trucks will be much more expensive than diesel trucks, but trucking companies are businesses and they will do the math and see the return on investment.
There are two markets: heavy-duty short range trucks (garbage, dump trucks, etc.) and long-distance highway trucks. Each needs to be optimized in different ways. A short range truck can probably get away with a 150-200kWh battery while a long distance truck will need something closer to 1mWh.
I think the hardest part will be delivering enough electricity to truck stops to charge 30-50 trucks at once at 500kW each.
There are two markets: heavy-duty short range trucks (garbage, dump trucks, etc.) and long-distance highway trucks. Each needs to be optimized in different ways. A short range truck can probably get away with a 150-200kWh battery while a long distance truck will need something closer to 1mWh.
I think the hardest part will be delivering enough electricity to truck stops to charge 30-50 trucks at once at 500kW each.
Shawn Snider
Member
Dump trucks require massive RPM's every time they 'dump', fuel cost sounds appropriate.
No.
First, the right unit for battery capacity is kWh, not kW.
So what? Electricity is different, usage models will be different.
What is the cost of full tank of diesel on modern semi? You thing usage models would not change to cut that cost down 10fold?
I feel like you have a very realistic view on the situation.
Electric trucks are going to cost more.... Upfront.
They need to be designed specifically for a more narrow use case.
Charging infrastructure on a large scale becomes very energy intensive.
The other main problem, I see, is that they will have to weigh more for similar range.
A lot of these problems are solved through autonomy.
The affordability of electricity also helps with the concerns of electric semi's. This includes the green concerns of burning fossil fuels. Semi's can operate at night and charge during both peak solar and peak congestion times.
Other limitation and infrastructure needs can be dealt with. These are 20th century problems, not 21st century problems.
JRP3
Hyperactive Member
Not likely. The trailer part of a tractor trailer is often an independent product from the cab, and can be interchanged with other trailers.
Also unlikely, as the added mechanics will add substantial cost and will have limited use, since most of the time the vehicles are in use during the day, and parked at night. That means a lot of expensive solar panels will be doing nothing most of the time.
No, because of the above mentioned reasons.
Probably a good idea
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