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Comment by agumonkey | Hacker News Reader

He didn't mention the semi ? The large flat area, long time under the sun, difference of market (no need to integrate it pretty, a simple flatbed on top would do)

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Semi trucks and trailers are two different components. Most trailers have a large flat area, but these can get swapped often. And even within the same company you won’t always have the solar trailer hooked up to the electric semi. The swappable nature of the load is part of the appeal of semis.

I guess what I’m saying is, even if you had a solar trailer, you would lose a lot of the load flexibility of using a semi truck. And you wouldn’t want to plan a load where you needed the solar power. So either way, you’re planning for charging at fixed intervals. Solar might help a little here, but not very much.

Couldn't it make the cost of shipping cheaper if the the load is able to contribute some energy to the truck?

You'd need some sort of standard for the trailer to provide electricity to a hybrid/electric truck but ignoring that (major) issue it seems like a pretty great idea.

But it makes the trailers significantly more expensive and the shipping cost more variable because the amount contributed by the trailer will be extremely variable. On top of that to cut down on cost you'd want the inverters to be on the tractor instead of the trailer but now you have truckers working around and having to plug and unplug live HV DC connectors as they connect and disconnect. Plus now the trailers are a hazard to worry about when they're just sitting around because there's all those solar cells creating big DC volatages just waiting for a circuit to be made.

I see, unless there's an army of solar trailers it's not useful.

Trailer manufacturers could make all trailers solar (panels on the roof of the trailer) and have a battery pack somewhere in the area a refer unit would sit. This way you could power the refer if there was one or the the Truck if there was no refer unit and the Truck was electric. They become a energy storage unit while not in use (sitting in lots). I think this is what we'll see when there will be more Electric Semi's on the road.

In a fantasy world unrestricted by physics and market and costs and raw materials, - yes, they could.

Wabash is already pivoting to special composites to lighten trailers for EV Tractors. I'm sure as new technology makes itself available they will start to think about solarizing their trailers. Right now they run their refers off of propane, switching to battery/electric would be a welcomed change. A trailer can spends days to weeks and even a month in a yard waiting for a tractor and could possibly charge a very large battery in that time. As a side note they could also add regenerative braking to the trailer axles.

> A trailer can spends days to weeks and even a month in a yard waiting for a tractor

Imagine what a similar investment in a stationary solar panel in that same yard would yield, a panel that will charge 100% of time.

>Imagine what a similar investment in a stationary solar panel in that same yard would yield, a panel that will charge 100% of time.

That will have to be rolled out by the yards not the manufacturers of trailers. Trailers are leased as very few companies buy them.

Semis use immensely more power than passenger cars, way more, proportionately, than is made up in increased surface area for solar.

It still doesn't work.

The only reason it might kind of work on a car is because it is only driven a handful of miles per week. Long haul trucks don't even make much sense to electrify with current technology.

Delivery trucks make a little more sense, but they still have the problem of being in motion for a large chunk of the day. Basically you're just slightly increasing your watt mileage/range on sunny days.

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