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How hard would it be to make an electric semi truck

jerry33

(S85-3/2/13 traded in) X LR: F2611##-3/27/20
Supporting Member
Mar 8, 2012
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Does anyone know the formulas or where you could find them to find the required energy to make this work?

When designing a truck, you start with the allowed axle weights for the jurisdiction(s) that the truck will be operated in. Then you subtract the weight of the components (body/motor/drive train/etc). The balance is the load the truck can charge for. If the balance not equal to or greater than the competition, you won't be able to sell any trucks.
 

Norbert

TSLA will win
Oct 12, 2009
5,507
1,827
San Francisco, CA

Not all semis have to go long distances. Some electric semis have already been used in the port of LA.

From that thread (I think we also had others, if that wasn't on another forum):

Electric Truck Can Haul a Trailer of Teslas | Autopia | Wired.com
balqon1.jpg
 
the problem is not electric motors, or torque, its just energy storage, and since regular chemical batteries suck, a capacitor would be better suited to the job assuming it can hold enough charge.
a battery cannot charge nearly fast enough for what semi's need, so the capacitor is the only option (you can charge a capacitor in seconds if you have enough power going to it, and you can cycle it tens of thousands of times)

a semi truck lets say has 200 Gal of fuel, that is 7600 kWHr equiv.
ICE are crap when it comes efficiency, the best engines are only 20% efficient, where as an electric motor can go as high as 97% and doesn't need a power train which robs more power.

[email protected]% = [email protected]%

if we need to store 1600kWHr worth of power to go the same distance you would need a capacitor with a rating of 46080 Farrads (500v)

the largest capacitor i've seen is a huge brick but only gets a rated 500F of capacitance, you would need 92 of these things...(the biggest one in the picture)

ultra_industry_tran_cameo_boost.png


if my math is totally off please correct.
 

ElSupreme

Model S 03182
Moderator
Jan 13, 2012
4,303
105
Atlanta, GA
the problem is not electric motors, or torque, its just energy storage, and since regular chemical batteries suck, a capacitor would be better suited to the job assuming it can hold enough charge.
a battery cannot charge nearly fast enough for what semi's need, so the capacitor is the only option (you can charge a capacitor in seconds if you have enough power going to it, and you can cycle it tens of thousands of times)

a semi truck lets say has 200 Gal of fuel, that is 7600 kWHr equiv.
ICE are crap when it comes efficiency, the best engines are only 20% efficient, where as an electric motor can go as high as 97% and doesn't need a power train which robs more power.

[email protected]% = [email protected]%

if we need to store 1600kWHr worth of power to go the same distance you would need a capacitor with a rating of 46080 Farrads (500v)

the largest capacitor i've seen is a huge brick but only gets a rated 500F of capacitance, you would need 92 of these things...(the biggest one in the picture)

View attachment 18861

if my math is totally off please correct.

Well diesel engines are actually in the high 30s for efficiency now. So about double your number for capacitors. Also Semis can have 300 gallons or more of fuel. As most have two fuel tanks of 100-200 gallons.

Also the power required to 'recharge' a truck 'quickly' would be enormous, and very complicated. And I think slow charging for Large trucks isn't all that hard to do. But honestly right now there is nothing that can compete with about 1,500 pounds of diesel fuel in terms of energy storage. Maybe aero-spec kerosene (read Jet/Rocket fuel).
 
How about an 18 wheeler with a ~ 30 foot trailer using solar panels/cells for the roof?

you could put ~4 kW on the roof of the trailer alone. That should help a little If batteries were under the floor and trailers could be 'stored' while not in use & pick up some power.
They would be pricey trailers but would pay for themselves in a matter of years
 

jerry33

(S85-3/2/13 traded in) X LR: F2611##-3/27/20
Supporting Member
Mar 8, 2012
20,193
25,799
Texas
The real trick here is the weight. Every ounce of weight added to the truck means less income because there is a maximum load per axle allowed by the highways department. There are exceptions, such as furniture vans, where volume is the limiting factor, but the majority of trucks run into the axle weight limit first.
 

K5ING

MegaMiler
Feb 6, 2013
293
65
Denton, Texas
I think that a possible solution would be to put the flat battery pack in a flatbed trailer, not the tractor, and use a removable container on top of the trailer.

The driver would drive to a dedicated truck stop or company terminal. A crane would remove the container from his now depleted flatbed and move it to a fully charged one. Swap the tractors, connect up, and he's off. 15 minutes max, and the trailer he dropped off could now be charged for the next driver.
 
The entire idea of the Class 8 rig is interchangeable trailers. To have the pack in the trailer defeats the purpose of this entirely. One of my friends is a driver for Target and once per week he makes the rounds in the downtown area, and the other 4 days makes 200 mile drives from the distribution center. On his city days he hooks up to 12 trailers in a day (drop off full to store, pick up empty to distribution center). The only exception is the downtown location is so small that he drives back to the distribution center without a trailer (and someone else picks it up later).

The energy has to be in the tractor and unfortunately it is a lot of energy required. If the energy density was significantly higher I think it would be a good solution to go electric. Most of the long haul drivers are stopped at truck stops for 8 hours plus which would give a great opportunity to charge the trucks without requiring super capacitors. Unfortunately if that is your solution you need to ensure the batteries are sized to take on a full days load (12 hours) with an 80,000 lbs load which means the batteries would need to be well north of 2 MWH.

If you were to electrify the class 8 tractors the only option that i can see in the medium future (once the density's at least double) is interchangeable battery packs. This will allow the truck stops to slowly charge their packs over the course of say 8-24 hours and make the switch on the tractor in under 5 minutes.
 

K5ING

MegaMiler
Feb 6, 2013
293
65
Denton, Texas
I was speaking mainly of long haul trucks, not city trucks. As for the long haul ones, as long as the trailer has enough power to drive for around 6 hours, it should work. When he stops for lunch/dinner, he pulls under a rig that hooks onto his container box and lifts it up enough to pull out from under it. He drives out and drops off the flatbed trailer to be charged back up, hooks up a fully charged one, pulls under the rig again and it drops the container onto the new charged flatbed. This could be done by someone else while he has dinner in fact. The load stays with the driver, not necessarily the trailer itself. He can't just swap tractors because long haul truckers basically live in their tractors. Of course, it wouldn't work with everything, but for most van-type trailers, there is no reason why it wouldn't.
 

igotzzoom

Active Member
May 26, 2013
1,219
611
Mission Viejo, CA
I don't know how purist you guys are here regarding battery EVs vs. fuel cells, but I think for Class 8 sized trucks, fuel cells might be a better solution than batteries. The only issue right now is that the vast majority of commercially-produced hydrogen is made from natural gas, so even though hydrogen fuel cells are theoretically "clean," as long as the H2 is still sourced from natural gas, they're still essentially fossil fuel-powered vehicles.
 

DITB

Charged.hk co-founder
Nov 13, 2012
1,581
36
Hong Kong
Very interesting subject.

When you make calculations, keep in mind how much of the diesel on a truck that gets lost in braking. Think of those highway hills where trucks are using brakes and low gear to avoid over-speeding on the downhill side. If that energy could be put back into the batteries, on an electric or hybrid truck, a lot of energy could be saved.

Remember this, mainly when you calculate how many gallons of diesel there is, and what it corresponds to in battery kWh.

Just like the automotive industry, I would expect a hybrid solution at first, possibly even a serial hybrid (saves a lot of weight and maintenance). Imagine a fully electrical drivetrain, with no gearbox at all (or a quite simple one), a smaller battery or capacitor, and then an electric generator optimised for a certain speed and constant output.

A turbine engine like on a jet or turbo-prop aircraft, connected to an efficient generator, oh that would be a sweet sound in a quiet neighbourhood! I am sure they would find some way to control the turbine noise, and a semi isn't exactly quiet in the first place. The high pitch turbine sound should be easier to contain than the deep frequency of a huge diesel.
 

RichardL

Member
Supporting Member
Oct 6, 2013
670
661
San Diego, California
Perhaps a good compromise is an 'electric assist' - where the trailer has a battery, solar and motor but is slaved to the tractor. So when the hitch is being pulled, the assist runs to reduce the effort of the tractor. When slowing down, the regen helps, and so on. So it needn't replace the diesel, simply make the combination more efficient overall.

Similarly, you could have an electric travel trailer.
 

ZsoZso

Active Member
Supporting Member
Apr 24, 2014
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Mount-island
IMHO, long distance cargo hauling should be done by electric trains -- far more cost efficient than trucking and you don't need massive batteries because of overhead wire feed. This technology has been available and in-use (at least in Europe) for many decades. The US had cheap gas and so they ditched the electric trains, even the few trains that are in use are diesel. Now that gas is no longer so cheap, it is time to switch.

EDIT: Of course, the last portion of the delivery in-town should be done by electric trucks, but those will not need to be so huge and don't need such long range either.
 
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Red Sage

The Cybernetic Samurai
Jul 6, 2014
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Hauling Where the Heart Is...

One thing I would like to see Tesla Motors do is to further the clean, renewable energy initiative of the company. Before long, naysayers will begin to note, as Tesla's sales increase, that they still use fossil fuel vehicles to ship and deliver their cars in the United States of America. I propose heading off that criticism by doing the unthinkable.

Tesla should create a line of long-haul semi-trucks that are fully electric. A Tesla Road Truck. They would be used solely by their own company. They would not be offered for sale to anyone else. They would be driven by Tesla employees, who were experienced long-haul drivers.

It would have to be comfortable, aerodynamic, and efficient. I imagine something along the lines of the better looking trucks on the road:

Some might say it would be better to work with one of those manufacturers to jointly develop the Tesla Road Truck. I don't think so. It's better to be completely independent. This is about proving that it can be done, proving that it is feasible, proving they can do it alone. Proving the technology can be not only competitive, but superior.

The trucks would need their own separate charging infrastructure to accommodate their size and power needs. That could be arranged two ways. Tesla could forge an alliance with a company such as the TA Travel Centers of America to place truck specific charging stations at their truck stops. If that were not possible, Tesla could build out their own, private lots across the nation to act as Tesla Waypoints for charging their trucks in transit across the nation.

What I like about setting up at the truck stops is that they are ubiquitous, across the country. Tesla could just lease space on site to install their own Superchargers. TA would get the added advantage of having solar panels installed at their locations in sunny Southern states, such as Arizona, Texas and others, to offset their own reliance on the electrical grid.

Beyond that, truckers love to talk about their rigs, as a matter of tradition. Tesla owners do that just as much as anyone else. So Tesla's drivers would become ambassadors of the technology as well, direct to their peers. And Tesla Motors could use their input to gauge interest, occasionally having test drive events for the trucks as well, hosted by the TA Truck Stops. Even if Tesla decided not to ever sell the trucks or go into full production of them, it might be just enough to convince truckers to beg for the technology from their traditional truck manufacturers.

If they had to build Tesla Waypoints, that would not be so bad. Logistics could be handled rather easily by internal systems. They could be sure that security for the cargo was aptly monitored. There could be sleeping quarters on site, along with provisions for food, drink, and entertainment during a driver's down time. In fact, it might be a good idea to set up these Waypoints at strategic locations, even if they did have a good deal with TA.

It might not be necessary for 100% of Tesla's deliveries and transports to be made with these trucks. If perhaps 30 to 50 of their trucks were on the road, that might be enough to get the word out. If Tesla intends to release a pickup truck around 2020 or so, it would be a good idea to have these road trucks in public view around 2017. That would be just in time for the ramp up of production for the Model E, so it would get that much more publicity. And that publicity would increase anticipation for the pickup truck, call it the Model P.

To that end, the trucks would need to have superior range. I'd manage that by co-opting the traditional design aspects of semi-trucks:

  • The large ones typically have three axles. So you'd might as well have three motors, working in unison.
  • There are usually fuel tanks on either side of the cabin, running nearly the full distance between front and rear wheels. Those could house stacked battery packs, formed to fit that space.
  • Underneath the cabin and what is typically the engine bay on trucks, you'd have the usual 'skateboard' arrangement of battery packs, from front to rear.
  • In addition to all that, you'd make use of the space behind the truck cab, by storing battery packs vertically, behind the sleeper area.
  • Yes, the engine bay would instead be a ridiculously large frunk.
  • Naturally, the car carriers they would tow would be properly aerodynamic, enclosed, and covered with Tesla logos.
With those many places to store batteries, I think it would not be hard at all to achieve a cruising range, under load, of around 1200 miles on a full charge. That said, knowing that most trucking services govern their vehicles by limiting them to 55-65 MPH max, I took that into consideration as well. Assuming 12 hours on the road, at 65 MPH, that comes to 780 miles. So if someone were to hit the road at a 90% charge, which allows 1080 miles range, they could drive 780 miles and still have a 20% charge remaining -- a 300 mile range buffer. They would park at a TA Center, or Tesla Waypoint, to charge while they rest. If it were a rush shipment, a different Tesla driver would attach their rig to the load and continue, relay style.

Yes, I know... This would cost a lot of money. But it is mostly for the sake of marketing. It would still cost less than running multiple spots on Super Bowl broadcasts over the next six years. And the trucks would likely be on the road 20-25 years. That makes the expense more than worth it.
 

JRP3

Hyperactive Member
Aug 20, 2007
21,202
52,517
Central New York
No. Tesla needs to stay focused on their plan for passenger vehicles and battery storage. Once they achieve all those goals maybe they can branch off. Tesla doesn't need the "advertising" you think a truck would bring, and how many people other than full time FUD stirrers really care if Tesla's cars are delivered by a truck, just like every other car? Besides, rail is far more efficient anyway, so they can just try to ship as many cars by rail as possible. Or build another factory in another part of the country when they need more capacity.
 

Red Sage

The Cybernetic Samurai
Jul 6, 2014
3,033
2,198
Los Angeles CA
I wrote, "Before long, naysayers will begin to note, as Tesla's sales increase, that they still use fossil fuel vehicles to ship and deliver their cars in the United States of America."
...how many people other than full time FUD stirrers really care if Tesla's cars are delivered by a truck, just like every other car?
Idunno. How many people believe that FAUX News and The Rush Limbaugh Show speak the gospel? Regardless of motivation, this is the Future Cars forum. I'm pretty sure that before passenger vehicles are largely electrified, Tesla Motors will work toward doing the same with heavy machinery such as long haul trucks as well. No, it isn't necessary in the short term. It would be cool to see in the long term.
 

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