I think that's pretty impressive!InsideEVs said:
The question is, how much do those battery packs weigh, i.e. what's the payload, and is this the 300 or 500 mile pack in the tractor? Coming downhill from the Gigafactory the range was not going to be the problem, except possibly for the 300 mile tractor in snow with delays; it's the loaded uphill run (I'm assuming they won't deadhead uphill, as that would be idiotic when the Gigafactory will need supplies from the Bay Area).RegGuheert said:
That's a good question, but even fully unloaded, this trip likely required the consumption of at least 300 kWh and traveled over 250 miles. As such, this is an important demonstration of the truck's capabilities. This route also demonstrates operation capabilities such as the operation of Megachargers at both ends of a route.GRA said:
"Coming downhill" makes it sound like these trucks just coasted 258 miles from the Gigafactory down to the main factory. In fact, while there was a NET elevation change of about -4500 feet from about 4500 feet down to about 50 feet, the trucks have to CLIMB about 2700 feet as they leave the Gigafactory to about 7200 feet in order to cross the Rocky Mountains at Donner Pass.GRA said:
That's true only as long as the trailers used for the batteries are compatible with the other loads. It is my understanding that many of the raw materials headed for the Gigafactory are containerized when they arrive in the Port of Oakland. Tesla may find that they need to load their batteries into containers in order to keep all of those containers from stacking up in Nevada. Since a fully-loaded Tesla Semi is simulated to consume about 630 kWh when traveling from the main factory up to the Gigafactory, the aero impact of a container trailer should not greatly impact the ability to accomplish this mission.GRA said:
In typical GRA fashion, you try to minimize accomplishments achieved by BEVs. In this case, you are doing it by completely ignoring the stated goal of Tesla to transport their batteries from the Gigafactory to Fremont using the Tesla Semis:GRA said:
I have long been a big proponent of companies consuming their own products when possible. There are many benefits which result from companies doing this. In the case of Tesla using the Semis to support their manufacturing efforts, this is an excellent way for them to live in their customers' shoes and share their experiences with the product. This approach ensures that the proper focus stays on the issues which exist in the Tesla Semi and encourages constant product improvement. They should also save money by doing this, assuming rail transport is not cheaper.Jerome Guillen said:
Should read "Sierra Nevada" (no Rocky Mountains in California).RegGuheert said:
RegGuheert said:
RegGuheert said:
It's from the link to the article which is same link that I provided for the estimate of 630 kWh the other way fully loaded. I should have linked it in that comment, as well. In a comment by "georgeS" we find:lorenfb said:
I couldn't find an unloaded number, so I guesstimated from the loaded one, figuring that wind resistance should be dominant given the net elevation change.georgeS at InsideEVs said:
I believe the economics say that these will be put on the road as fast as they can be made by Tesla and others. I think the other manufactures will lag for a while as Tesla ramps up production. They aren't likely to do a lot until Tesla starts eating their lunch.lorenfb said:
I didn't see any mention of Megachargers in the article, but I just skimmed it. Was that mentioned?RegGuheert said:
Reg, like most northern CA skiers I've made the drive (both ways) many times, so I'm well aware of the elevation changes. Coming from the Gigafactory through Reno, and then winding through Truckee Canyon and often all the way up to Donner, the speeds are often restricted. More importantly, if a 300 mile tractor leaves the GF fully charged, the 60 miles/+2,800 ft. to Donner Summit opens up room for regen, which will be gained at a very high rate (this stretch westbound is where the truck runaway ramps are located) until you get down to just past Penryn:RegGuheert said:
The packs should fit in a container no problem (internal width about 7'8" IIRR, although whether or not the packs can be loaded lengthwise side-by-side may be a problem), the issue will be do they have to transport special racks up the hill to stack them, if so do they fold, and what do the racks weigh? I've used (non-folding) racks similar to the one on the right end of the upper gallery row here: https://tier-rack.com/application/shipping-racks.html (the picture just left of that shows the same rack folded), but there's no way they could handle the weight of a battery pack, even if putting that much weight that high up were acceptable. A battery pack could use a much lower, stronger rack. As battery packs are dense commodities maybe stacking won't be required, and using regular dunnage (plywood, foam, pallets, inflatable bags) and shipping them in a single layer will be okay.RegGuheert said:
Reg, I'm not ignoring that they plan to do this, I've said upthread several times that this is an excellent use for these tractors, and a good way to demonstrate the product. But a single run in good conditions is a long way from a fully operational vehicle. If they'd made the run last week, when it was snowing heavily and blowing hard along I-80 in the Sierra they would have gotten some data in worst case cold conditions, but given how new the tractors are and the inevitable problems that will arise even in good conditions, that wouldn't have been wise for a first run.RegGuheert said:
https://www.sfgate.com/news/article/Even-after-storm-California-officials-find-12729418.php The likelihood of major winter storms (which have been notably absent this year) this late in the season is increasingly unlikely.
RegGuheert said:
Diesel trucks achieve a Carnot efficiency of 75%? Hardly.lorenfb said:
SageBrush has an excellent post which includes all Class 8 semi per-mile costs and you can see that the fuel costs match my estimates very closely (image from this reference source):RegGuheert said:
I surmised that from the fact that they drove the trucks both ways. I had thought that is the only charger available for these trucks. But it seems that at least *some* of the prototypes can be charged using Superchargers, including one of the trucks used in this demonstration:GRA said:
andInsideEVs said:
So that raises a whole host of questions:InsideEVs said:
Yeah, that's why I called you out on characterizing this trip as "downhill".GRA said:
Thanks, I considered that the batteries will need racking (I'm willing to bet that they do), but I hadn't thought about getting them back up the hill. Perhaps those can be transported back up with many of them in a single load.GRA said:
You're kidding, right? I think it would be extremely foolish to make early test runs in poor weather for a large number of reasons.GRA said:
RegGuheert said:
:?: :?: I have no idea where you came up with that idea. I have estimated that an unloaded BEV semi's consumption is reduced from 378 kWh when fully loaded to about 300 kWh when unloaded. That is roughly 80% of the energy consumption needed by the fully-loaded truck.lorenfb said:
