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Discussion Starter #2
Highlights:

320kWh battery pack
6 motors, 2000hp peak
natural gas turbine range extender
independent suspension on all six wheels
2 speed transmission on each wheel.
 

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Discussion Starter #5
It's a good start, although for a trans-continental truck I'd prefer to see a flow battery rather than a turbine/generator.
A flow battery would be interesting. The ability to independently scale power and capacity has a lot of advantages in this application. The company that is building this started out in fleet natural gas systems, so they weren't that interested in other options, but it would be interesting to see how big of a flow battery it would take to achieve the 1000 mile range and 400kW output of the turbine (the main battery supplies the rest of the power for 1.5MW peak)
 

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A flow battery would be interesting. The ability to independently scale power and capacity has a lot of advantages in this application. The company that is building this started out in fleet natural gas systems, so they weren't that interested in other options, but it would be interesting to see how big of a flow battery it would take to achieve the 1000 mile range and 400kW output of the turbine (the main battery supplies the rest of the power for 1.5MW peak)
Yes, but interestingly weight is not as much a factor for a trans-con truck (and even less for a train) as you would think. Turbines are extremely expensive, although fairly dependable.

I especially believe flow batteries will be the trick for trains. You can simply hook up a couple of extra tank cars for the electrolyte, and change them when / where you change drivers (putting the discharged tanks on a charging station). As solar becomes ever cheaper in the South, we may start to see trains pulling hundreds of tank cars north replacing coal and oil carrying cars.
 

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Discussion Starter #7
Yes, but interestingly weight is not as much a factor for a trans-con truck (and even less for a train) as you would think. Turbines are extremely expensive, although fairly dependable.

I especially believe flow batteries will be the trick for trains. You can simply hook up a couple of extra tank cars for the electrolyte, and change them when / where you change drivers (putting the discharged tanks on a charging station). As solar becomes ever cheaper in the South, we may start to see trains pulling hundreds of tank cars north replacing coal and oil carrying cars.
That's definitely true for trains, but for trucks regulations cap the gross weight at 80,000 lbs, so that's a big hard limit.
 

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That's definitely true for trains, but for trucks regulations cap the gross weight at 80,000 lbs, so that's a big hard limit.
So, they might have to fill up a bit more often. That still might not be awful if at least the truck stops along the interstate started having flow battery fueling stations. Such a station would require both a fill and a drain hookup, but since charging would occur all the time thus moving the discharged fluid to the charged fluid container the "tanks" would rarely require refilling except for spillage.

Trucks routinely carry 150 gallons of diesel, just shy of 1,000 lbs. Even if they carried 600 gallons of electrolyte (which admittedly would still not have the range of 150 gallons of diesel) you would only ding capacity by 3,000 lbs out of 80,000, or less than 4% of total gross weight. If your "fuel" cost only $1 per gallon it would be worth it to the large carriers to have their truckers stop more often to refuel. It would also be healthier for the drivers to get out more often and stretch.

Such a vehicle could also use regenerative recharge, possibly regaining a large portion of energy used to climb mountains.
 

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Just spent a weekend with a trucker sharing my home, then re-read the specifics of this article. 320Kwh is definitely a lot of batteries (about equivalent to 40 gallons using our previous 8Kwh/gallon rule); you could make up some of that weight by switching to a microturbine, but any other solution would definitely start chewing into the 80,000# limit. That pack has to be really heavy! But, if it can cut energy use 50% it might pay for itself over time.
 

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Around 4500 lbs when all is said and done. But they make up for it with a light turbine and a carbon fiber body, so the tractor is actually a little lighter than a typical Diesel tractor.
That still has to be a whole lot heavier than the 500hp diesel engine, and you still have to carry fuel.

I am curious how they came to the conclusion of how large the battery pack should be. The Kwh equivalent of 40 gallons is 20% of the 200 gallon load my friend's truck carries (actually 220 gallons). A 240hp turbine engine weighs around 150 lbs, don't know how much the generator weighs and you still need to add electric motors and possibly keep the gearbox. Less than a diesel perhaps, but still a lot of weight with a 5,000 lb battery pack.
 

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Discussion Starter #13
That still has to be a whole lot heavier than the 500hp diesel engine, and you still have to carry fuel.

I am curious how they came to the conclusion of how large the battery pack should be. The Kwh equivalent of 40 gallons is 20% of the 200 gallon load my friend's truck carries (actually 220 gallons). A 240hp turbine engine weighs around 150 lbs, don't know how much the generator weighs and you still need to add electric motors and possibly keep the gearbox. Less than a diesel perhaps, but still a lot of weight with a 5,000 lb battery pack.
The battery was sized for specific performance needs, not necessarily just battery only range.

A 450hp Cummins Diesel weighs 3000 lbs. So the battery pack itself weighs more than that. But the rest of the powertrain is relatively light, and like I said, the carbon body allows the overall weight to be a couple hundred pounds less than a traditional tractor.
 

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The battery was sized for specific performance needs, not necessarily just battery only range.

A 450hp Cummins Diesel weighs 3000 lbs. So the battery pack itself weighs more than that. But the rest of the powertrain is relatively light, and like I said, the carbon body allows the overall weight to be a couple hundred pounds less than a traditional tractor.
Well I hope it all works. I do know that the turbine I linked was not necessarily a high-efficiency one, nor might the weight be the same as what they choose for the truck. Now that I think about it, 20% of normal "fuel capacity" might be minimum to make it all work well. It takes about 100hp on straight and level at 75mph for a semi, according to my friend. Your turbine will need to produce more than that to be able to charge the battery while driving, but you want the turbine to be of less power than the diesel to minimize starting and stopping the turbine while still allowing enough juice for a full-power (genset plus battery) long mountain climb.

The next piece of the puzzle is that the turbine, too, needs fuel - and even if it is more efficient than the diesel it will still want about 150 gallons, or 1,000 lbs of fuel. You might trim that to 100 gallons / 650 lbs. But, it may be possible to have electric motors on all 4 drive wheels ala' Tesla, and thus eliminate the transmission - which might save another 1,000 lbs (roughly, I actually have no idea how much they weigh but they look heavy). If the computer(s) controlling it all are smart they will be able to detect slippage independently on each drive wheel, which would provide a huge improvement in safety.

On that final point alone, a modest weight penalty might be worth it.
 

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Discussion Starter #15
But, it may be possible to have electric motors on all 4 drive wheels ala' Tesla, and thus eliminate the transmission - which might save another 1,000 lbs (roughly, I actually have no idea how much they weigh but they look heavy). If the computer(s) controlling it all are smart they will be able to detect slippage independently on each drive wheel, which would provide a huge improvement in safety.
All six wheels have motors. Other than that, this is correct. Combined with this and the independent suspension on each wheel and the very low center of mass, this should be the most stable and safe tractor by a lot.
 

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Tesla doesnt have a motor on each wheel. It has one motor per axle and a reduction transmission (plus differential) for front and another for the rear.
The "Nikola" truck proposes to use a 400 kW turbine to charge the pack and a motor with 2 speed reduction for each wheel.
That is not a lightweight asembly.
Also their comparison of torque, 1650 ft lb for diesel, vs 3700 ft lb for electric motors, seems to forget the multi ratio transmission used on the diesel which would effectively give 20,000+ ft lb at the drive wheels !
There is too much "selling" and "money magic" wrapped up in unproven technical claims, to make this realistic.
I call virtual bullshit until something more than a few CGI graphics are presented !
 

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Also their comparison of torque, 1650 ft lb for diesel, vs 3700 ft lb for electric motors, seems to forget the multi ratio transmission used on the diesel which would effectively give 20,000+ ft lb at the drive wheels !
Yes, the torque multiplication capabilities of a 20 speed transmission are nothing to sneeze at. With a higher torque motor you can probably get by with fewer gears, but not just 2 or 3.
 
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