Reader Question: Electric Motors for Trucks?

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Here’s the latest reader question, along with my reply!

Arthur asks: If a truck trailer had an electric motor it could increase fuel efficiency and control. If the power were to come from the tractor, which is already producing power, then we don’t need all the weight, expense, short life, hazardous waste, etc. of the batteries. How much power does it take? Would the tractor motor need a larger alternator or a large, heavy expensive generator?

My reply: I’m trying to understand your question! I think you’re asking about big rigs – commercial heavy trucks – and whether it would make sense to add an electric motor to the drivetrain. I don’t see how it would. The electric motor would duplicate effort, add complexity to the system – and weight.

As with electric cars, the better question to ask is: Why?

Why bother with electric anything? It isn’t necessary or needed and there are no practical advantages which aren’t outweighed by the disadvantages – which are several and serious.

Electric vehicles remind me of an old country saying about the guy who goes around the block to cross the street . . .

The real problem besetting truckers is government – which is systematically strangling their ability to work and earn a living. The government is killing off diesel big rig engines with regs subject to no reasonable cost-benefit analysis (as with car emissions regs) that seem to have been designed deliberately to destroy the industry. The drivers themselves are pecked bloody by regs limiting practically everything they are allowed to do.

It’s a wonder there’s any food at the store. Of course, many people just assume it appears there, magically – and don’t consider what would happen to them if the trucks stopped rolling.

Got a question about cars, Libertarian politics – or anything else? Click on the “ask Eric” link and send ’em in!

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  1. I suppose in theory heavy trucks could use diesel generators and electric drive motors as do railroad locomotives. But they don’t so I suppose there must be no advantage at that level of weight.

    In theory heavy trucks could also use electric motors driving the trailer wheels for additional traction up steep and slippery slopes. But apparently tire chains and just waiting until the road is clear is a more economic solution.

    • Trucks have to haul 80,000 pounds at 70 mph. The motors would need a multi speed gearbox to handle the different speeds. they work at 0 rpm but are inefficient and unreliable in full throttle low rpm situations.

      The cheapest solution would be replacing the alternator with a motor/generator. It could add torque and would be in the efficent rpm range all of the time without adding systems.

      Powering the trailer wheels could lead to some handling issues as the trailer is sometimes at a different angle from the cab and could push it sideways. Also would you use 6 motors? 1motor+ A 50 ft driveshaft and differentials? Power just 2 trailer wheels? You could just use a little electric power to effectively lighten the load to get over slick roads, and electric braking could make the truck slow down more safely than air alone. But then there is the matter of the 1200 volt extension cord running from the tractor to the trailer over salty dirty mountain roads

      But trailers are often swapped out. Driver 1 runs out of time for an overnight, so driver 2 picks it up and delivers it. Or driver drops off a full trailer, picks up an empty so he doesn’t have to wait. No one wants to drop off the $100k trailer for a regular one, and fleets dont want to invest in a million new electric trailers

  2. With all the massive regulations that truckers have to deal with, it’s amazing there hasn’t been a huge truckers strike. Of course it doesn’t help that some of the regs are at least partly written by the rent seeking large trucking companies in a attempt to push out the smaller operators.

    • Many retirement age people are becoming truck drivers due to lack of career options, and also many truckers are imported. As bad as our regulations are, its better than living in india or africa. And my brother keeps trucking cause hes 400+ pounds unskilled and slow as a turtle. and he doesn’t want to live anywhere near a city.


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