Self-Powered Trailers Promise Leaner Freight Runs | Hacker News Reader

Self-Powered Trailers Promise Leaner Freight Runs

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68 pointsrbanffy68 comments

In the US, commercial trailers are used like these crappy sheds, you go get one and the ABS unit is gone, the only thing worth stealing. For any company where this doesn’t hold it’s a big deal. The bigger deal is really RV trailers. You power assist, with simple motors controlled by pulling, and you can pull a huge one with ANY car, you don’t need truck, just modified mirrors. Plus the RV trailer benefits from slow self movement and power wall when disconnected. Total off grid tiny home.

In practice it's of course not so simple. Every truck that passes you (or that you pass) will suck you right in if your tow vehicle isn't heavy enough or you don't have good enough grip. Also, (RV/drum) trailer brakes suck so hard that you really want a vehicle with some additional stopping power other than regular brakes (heavy duty transmission, big engine, and diesel exhaust or compression brake). E-brakes work well so there the e-assist trailer has a real advantage if it can do that but you'll have to get used to the feeling of being pulled back rather than leading the stop... So evy 6.7l diesel I tow a big RV and e-assistance would be very welcome but costs likely drastically reduce the attractiveness of such a system for an RV. For a trailer that's constantly on the road I can definitely see a use case but it's not to be towed by a (comparatively) tiny car

Yeah, driving semi on tight two lane roads there’s be a whip cracking sound when we passed by other semis close, the two air vortexes colliding.

But I think it’s surmountable. Someone in this thread joked you could put the steering wheel in the RV, which is of course done, so really it’s just a question of RV motion not compatible with car. I could imagine problems with this, if the stopping distance of the RV is higher as it is in loaded semis, you need a feedback mechanism to the car not destroy the brakes of the car, same with pulling. Really the advantages are too high, solar charging, weeks of battery, ability to slow move with no car, but no restraints of being a motor vehicle.

Or flip the narrative and put the steering wheel in the RV trailer and tow your tiny car behind it!

Wait...

lol! Good point: Really it’s the integrated vehicle components that make motorhomes cost so much more than towables. In trucking, the triples trailers don’t have front axles, they’re added through converter dollies. That’s really all you need to make this work, a motorized steerable converter dolly and you can use it with any existing trailer. It only needs to be able to steer, maybe through combining different wheel speeds. they are basically moving trailers already this way with robot Dollies in China.

Realistically you can digitally tow the trailer at that point, you don’t even need the connection, just the promise the trailer following your tracks and staying close behind.

Obligatory VW trailer assist ad:

https://www.youtube.com/watch?v=bvZuSxibyYE

> Every truck that passes you (or that you pass) will suck you right in if your tow vehicle isn't heavy enough or you don't have good enough grip

You'd think you'd ever see some evidence of this happening and right now at the height of Tourist Season you'd expect to see the roads littered with smashed caravans, but no - it does not appear to happen.

It has happened people I personally know. It wasn't just a truck passing, it was a truck passing with a good cross wind, which is why it isn't common. This wasn't a small tow vehicle, it was a F350 which is a large truck even by US standards, and it has a heavy duty frame. At least the truck was strong/heavy enough to say out of the ditch and could safely be moved to the side of the road unlike if it was a smaller tow vehicle.

> and you can pull a huge one with ANY car, you don’t need truck, just modified mirrors

So pretty much like everywhere outside the US?

Here in the UK it's not uncommon to pull a 1500kg caravan with a bog standard Ford Focus, without any problems at all, and well over two tonnes on a twin-axle one with something like a Volvo V60.

People come from all over Europe to holiday here with their caravans, and are towing them at "realistic Autobahn speeds" behind perfectly ordinary cars.

It just seems to be the US where you need a 7.5 tonner to pull a trailer the size of a suitcase.

Those are small trailers that you can pull with small cars in the US. The US has many RVs that need much larger trucks to pull them as well. I don't have much autobahn experience, but I don't recall ever seeing a RV type trailer like are somewhat common in the US.

Even if your car can pull the trailer, that doesn't mean you should. If the trailer is oversized the car and engine can pull it - but you need something much bigger/heaver to control the load if anything goes wrong. More than one person has had their car roll because they were towing a large trailer at high speed and a wind gust pushed them into the ditch. If they were towing at city street speeds they would have been okay, but not autobahn speeds.

You don't need a 7.5 tonner to pull a small trailer. However you do need to carefully check the tow rating, bad things happen if the tow vehicle is too small. You do need a 7.5 tonner to pull a large trailer though.

European caravan trailers are generally designed with a much lower tongue weight, like only 4%. This reduces strain on the tow vehicle at the cost of reduced stability. It is ridiculously dangerous to tow such a trailer at full "Autobahn speeds". You might be able to get away with it on a straight road if nothing goes wrong but a sudden maneuver or even a strong gust of wind can lead to uncontrolled oscillation and a roll-over crash.

https://www.theautopian.com/heres-the-physics-behind-tongue-...

US trailers are generally designed with something like 10-15% tongue weight which allows for much higher dynamic stability but also requires a much stronger tow vehicle. As usual there is no free lunch in mechanical engineering.

Uh, you still need suspension on the tow vehicle capable of the tongue weight. And enough mass that a gust of wind doesn’t push you over a lane.

This would be based on a different wheel configuration. The control shaft fixed to the car essentially works to steer a pair of front wheels, and may steer back wheels to minimize off tracking.

Cool, but I don’t see the real benefit. Electronic trucks already work quite well, start at around 150k (vs. 150k for a retrofitted e trailer), and are afaik mostly limited by the charging infrastructure. If you now add a an electronic trailer to your diesel truck, you now also have to care about charging.

Yes, in Europe the legally required rest periods can already be used for efficient charging, but this is not an benefiting exclusiv to the trailers, but for general electronic trucking.

Charging time. A truck/driver doesnt remain stopped. It drops a trailer and picks up another. And a truck needs charging on the open road where there just are not any charging stations. But a trailer remains parked at a loading bay for hours, a commercial facility where installing chargers makes sense. A trailer therefore has more oppertunity to charge than a truck.

And if a company wanted to, parking a trailer to let it charge is far cheaper than paying a truck/driver to sit around.

But that's the thing: you already have to pay a driver to sit around!

In Europe there's (simplified) a mandatory 45-minute rest break after 4.5 hours of driving. Similarly, there's a mandatory 11-hour rest period after the daily maximum of 10 hours of driving. And it is very strictly enforced, with every commercial truck having been equipped with a sealed and certified data logger, plenty of random checks by traffic police, and heavy fines for any kind of violation.

If the truck is already sitting idle ~half of the time due to driver rest requirements, why not take that opportunity to charge it as well? Similarly, if you are building the usual highway-side rest stop with truck parking, a petrol station, and a restaurant, why not add a charging station as well? It can even do double-duty as rapid car charger!

In Europe (at least in Germany) we already have a lack of truck parking spots along many routes. And that's with parking spots that are just a bit of Asphalt and maybe a portapotty, or big asphalt parking lots attached to a rest stop

If we had enough chargers that any trucker could pull into a truck stop at their prescribed rest period and find a free charger, electrifying trucks would indeed be a no-brainer. But in the world we currently live in we don't have enough chargers to make that reliable. We barely have enough non-electified parking spots, and in your world they would all have to be electrified as well. It's a mix of a chicken-and-egg problem on the commercial side and a lack of will on the government side

But there is never a lack of will from the government to try all kinds of pilot programs that look cool but are mostly caused by the need to somehow sidestep the lack of sufficient charging infrastructure

I have driven a lot in Europe and a lot in the night (I like to avoid traffic jams and use the no speed limit on the autobahn), I have to say that this does almost exclusively belong to Germany in my experience. Which makes perfect sense because Germany is in the center, has a lot of truck traffic and long autobahns so it makes sense the parking lots are limited. I have not seen this in any other country other then quite exclusive circumstances.

I guess the problem is that they don't charge for these parking spots, hence they are underprovided?

At least from the truckers I watch on YouTube from Germany, there is already a shortage of rest stops for trucks. Sometimes you can see them even in the entrance of the rest stops, parked in a dangerous spot. If they all have to charge, then that becomes a problem, because they can’t find a space even „creatively“.

Not saying that electric trucks are bad, just one more problem to solve

Yes, I was thinking about this exact situation (drivers waiting around in the "wrong" spots). But that is already a problem, which should be fixed, whatever energy the truck uses. So if they should increase parking spaces anyway, might as well add charging infrastructure while at it.

Yes, I know it's a bit more involved than just pouring concrete and calling it a truck stop, but at some point politicians need to actually do something about this push for electrification.

The hard part is getting the NIMBYs to let you build any truck stop. Adding a bunch of chargers afterwards is a piece of cake.

That's interesting. In blue collar parts of USA it is not too bad to get a truck stop in. Truckers are a constant flow of money into town that is welcomed, and more importantly they just stop at the highway exit area and then get the fuck out after shedding their currency without going into actual town where the residents live.

The electric truck doesn't make anything worse here, does it?

So build them stops.

Not all trucking is the super trucker pissing in a jug OTR stuff you see on youtube (those are the guys with the most down time to make youtube content though). There's god knows how many LTL and reefer fleets doing local delivery and mostly home at night that could benefit from something like this.

That said I don't the cost is low enough for them yet.

In the US, truckers outside of truck stop have very few places to park. Truck stops and rest areas are already crowded st night. Trucks often have to park illegally on shoulders and offramps, because a lot of times they don't have the hours to make it to a destination. If we don't even have parking infrastructure for trucks how are we going to build enough charging for all of them. You gotta park before you can charge.

I think many long-haul truckers work in pairs for this reason?

You can, but (at least in Europe) it is rarely done.

A big problem is that it doesn't count as a daily rest if the vehicle is moving. This means in practice that the longest you can drive in pairs is 4.5h A, 4.5h B, 4.5h A, 4.5h B, 1h A, 1h B, followed by at least 9 hours downtime. Still a 20-hour non-stop drive, but not even remotely 24/7. You'd need additional standby drivers at a remote base, at which point you could also just swap the trailer to another truck.

In practice this means it is rarely worth it. Combine it with the schedule going out-of-sync with the days, and for regular freight it is almost certainly more expensive than just giving each driver their own truck.

The exception to the rule is high-priority cargo which for one reason or another can't be done via air. Take Formula 1, for example: with back-to-back races they have just three days to tear everything down, drive it across Europe, and build it back up again. It's a 15-hour drive without any delays, so having a solo driver rest for an additional 9 hours halfway through is unacceptable. With a driver pair it is easily achievable, and the additional costs are irrelevant.

Regulations are a bit different, not just on what counts as rest, but on physical format.

The normal US front-engine is rare in Europe.

The US extended sleeper generally doesn't exist in Europe

The European compact cabover generally doesn't exist in the US.

The scale influences this more than a little bit. The longest drives you'd find it sensible to make hauling freight inside Europe are between 12 and 18 hours of nonstop travel, while in the US they're more like 40-60 hours.

And split the revenue? No way Jose. Team driving is not preferred.

What are you talking about? All of the major long-haul trucking companies hire team drivers.

https://schneiderjobs.com/truck-driving-jobs/driving-opportu...

Yes, they do, and you should look into how team drivers are paid. It’s not a good deal.

So again, team driving is not ideal for the worker, only the mega carrier. You’ll make less as a team driver than a solo driver.

I suppose the trailer has a lot of space for solar panels on top, which the tractor does not. But those could be connected to the tractor rather than the trailer. Of course

Last time I ran the numbers, in ideal situations a truck/trailer could generate enough power from solar alone to drive on the highway. Ideal means the truck is already at speed, it is towing multiple trailers (length is only legal in a few states), they are used the most efficient solar panels made (significantly better than the mass produced panels most people are putting on their house - at a massive increase in cost), it is near noon, and it is near the equator.

This wasn't a discussion over whether panels were sufficient to push a truck. It was a discussion if the tractor unit or the trailer was the best place to electrify

These paired with Janus Electric[0] conversions would make a hell of a road train.

[0]: https://januselectric.com/

It’s an interesting idea. A company called Hyliion https://www.hyliion.com/ tried something similar here in the US about 10 years ago. Unfortunately, they weren’t able to have success in the market and ended up pivoting to power generation for data centers.

This trailer saves 7000l of diesel per year. Assuming 40l/100km, with this trailer you can go ~17.000 km more, which is 11-17% more, for the same fuel cost. Or ~12-15k EUR in fuel savings per year (assuming 1.8EUR/l).

With 13+ years ROI (electricity is not free) is this really beneficial?

Maybe you shouldn’t throw out your new trailer, but it looks like a good deal for expanding a fleet.

Remember that all signs point towards more CO2 fees and higher gas prices in the coming years

I'm not seeing any sign of CO2 fees increasing in the USA. If anything, they'll be federally outlawed.

Not in the next 3 year. However there are more elections coming up. And other things changing. For that matter even if the US does nothing, other countries doing something will forced changes. Petro cars are so cheap in the US (they are not exactly cheap) in large part because the design costs are amortized over so many buyers, when the rest of the world isn't buying them that drives up costs in the US.

Meanwhile I'm not the only US driver who has discovered how much cheaper a EV is, so even without CO2 fees things are changing - just slowly.

> With 13+ years ROI (electricity is not free) is this really beneficial?

Regenerative and solar electricity is free, and regen braking additionally saves wear and tear on brake pads.

The real benefit I think is when stuff like tax codes, carbon credits and government subsidies come into play and ROI goes down significantly.

Or when the next war hits and diesel actually hits and bypasses the 2.50€/l mark.

> The real benefit I think is when stuff like tax codes, carbon credits and government subsidies come into play and ROI goes down significantly.

Those are unreliable and vary at the whim of the government and their need to fill a hole in the budget. The only reliable factor here is a subsidy on the purchase price for the trailer as that can not be withdrawn after a year. Carbon credits will disappear as soon as a significant part of transport has been electrified, electricity prices are still rising, tax exemptions are temporary at best.

>Those are unreliable and vary at the whim of the government and their need to fill a hole in the budget.

Sure, but that doesn't matter to the guy buying the trailer. They got a tax break, credit, whatever, and through the magic of financialization they sold that tax break for $.92 on the dollar. So they don't really care what happens. And the $.08 hedges the middle man's risk. Etc. etc.

I think a cool application is that someone with a remote control could park these or manipulate them in the logistics park while the tractor trucks can immediately pick a different trailer and leave

That adds a lot of complexity. You'd need a steerable axle somewhere, for starters.

The usual tool for this is a mini-truck called a "yard goat".[1] There are also forklift attachments for this job.

[1] https://www.totalwarehouse.com/lonestar-battery-powered-trac...

You could join lots of these together, put them onto a pair of parallel metal beams and move them between major hubs.

C'mon. That's so stupid! It'll never work. You'd have to put so much metal in the ground. Way too expensive! It'll never happen. What if the ground isn't flat? Huh? Did you think of that? Or if there are any curves? Metal beams are straight, so there's just no way it'd work.

AI could largely do that.

I have a hard time seeing this adopted in many markets due to overall system complexity and weird new edge cases.

Trailers are supposed to be pretty dumb. This is what makes them valuable from a logistical perspective. If we hyper focus on reducing the carbon footprint of each specific shipment we may find we created an overall increase in aggregate once the higher order and deferred consequences come to bear.

It saves 7000 L of diesel on one year, but what is it compared to the spending in total? What is the percentage of saving?

Brave new world for the kinds of people who steal catalytic converters and the copper off air conditioners!

It'd be nice if researchers compared the impact on environment of disposing of the batteries (toxic metals, chemicals, other components) with the impact on the environment of the truck burning fossil fuels. In the end, what's the net benefit? Maybe it's great, I don't know. I feel we're getting a very one-sided assessment, though.

These are old talking points from the fossil fuel industry. The batteries themselves will be recycled to recover their valuable minerals. The process will certainly require care to avoid localized pollution. Compare that with burning fossil fuels- baked into their design is emission of heat trapping gasses which systemically affect the entire planet. It’s clear we need to stop burning fossil fuels lest we overheat the earth.

It is not a given that recycling lithium will be economical, if it’s more expensive than manufacturing new why bother?

Worst case scenario we dig up more lithium. I'm convinced the Nickel and Cobalt will be recycled. Lithium is a small percentage of total mass, 1-3%, and is abundant in the earth's crust. Maybe 5-10kg of lithium in a pack. Compare that to 40-80kg of petroleum every time I fill the tank.

https://www.npr.org/2026/07/13/nx-s1-5847025/ev-battery-recy...

That's what's called a life cycle assessment and these are standard in products like this for a long time. If they came out negatively, you can be damn sure that the fossil fuel industry would make us know.

CO2 increasing is a pretty one-sided and horrible effect, too. It's by far the dominant problem.

OP is asking about the environment impact of manufacturing this.

Like the whole supply chain for these trailers produce CO2 for each trailer it outputs.

I had a similar thought as my city replaced 500,000 curb side recycling bins because of the color. How many years of my personal environmental savings did that operation cost? They had people flown in from the other side of the country for months just to offload the bins from the trailers.

At what point does the second and third order side effects action offset the benefits.

Even a version without AC charging (just solar + regen) with a smaller battery seems like a good deal

The amount of solar power available to the square area on top of a trailer is negligible compared to the energy required to haul it long distances. Regen braking would probably only be worth it in some limited circumstances.

"Pavel Gilman, vice president of sales and marketing at Nivalis, breaks down where those savings come from: roughly 30 to 35 percent from the electric axle during braking and deceleration, 11 to 15 percent from the rooftop solar panels, and the remainder (roughly half) from grid charging during parking stops."

11..15% Is not the bulk of the energy. But it's significantly more than "negligible".

Note that this trailer could be expected to be on the road most of the time. Which may not even be the common case: demand for goods varies a lot, so I'd expect that a lot of logistics companies aren't fully booked all the time. Maybe have a few drivers/trucks on the road, and a bunch of trailers on a parking lot doing nothing. In that scenario: need a trailer? Use whichever one is charged up furthest, while at a loading dock top it up (grid power/in-building storage) to whatever is needed to complete the trip, off it goes.

Also for US-based naysayers: Europe is a very different environment than the US. Most long hauls aren't that long, and there's a lot of [industrial zone local distribution center] <-> inner city traffic. Read: lots of start-stop, low speed cornering & wait time.

What's your math on regen braking only being worth it. in limited circumstances?

The placement of the Krone pack in the photo at link, makes me laugh: it would never survive in the USA, given the way truck drivers drive and the bumps and curbs etc. that trucks drive over. It would be ripped off or at least heavily damaged within 50K miles.

Maybe some truck drivers. However there are also a lot of trailers in the US that hang even lower than this appears to. The most common situation is trailers have a lot of space between the floor and the ground - so a forklift can drive all the way in. However some trailers - those used for house moving for example - have much lower floors. They have more space inside which is good for lighter things you are putting on the trailer by hand.

So, what you're saying is, we should be preventing shitty drivers from operating 40-tonne lorries?

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