Hacker News Reader

Comment by castratikron | Hacker News Reader

This is where it'd make sense for the battery to be removable. A truck company could keep a bunch of charged batteries at their warehouse and swap batteries out every time a truck comes back for a new delivery.

View on HN

If manufacturers were smart, they would make them easily moveable by forklift.

Battery powered forklifts swapping batteries on trucks. It's a nice image of the future. Perhaps there's even infrastructure commonalities to reduce costs.

I think it's much more likely that a) it's not that easy; and/or b) the economic incentive just isn't there rather than people whose livelihood depends on it not being smart enough to figure out that forklifts exist.

When I worked in plants, I remember gangs of battery charging stations that had a crane to swap batteries out on the forklifts. I can't imagine distribution centers not installing something like that for these trucks (eventually). Even if swapping isn't a feature in all electric trucks to start, there's almost certainly going to be some sort of conversion kit to make it possible in the future.

Why does this make particularly more sense for trucks than cars? Just because trucks don't need to have a down time for sleeping like a car with a single owner does?

It's a perception win, as their diesels produce a lot of soot (not so much anymore, with the DPF and urea injection, but .. perception).

They need a lot of torque to accelerate (err, "gain momentum") away from lights, and the instant torque of an electric motor is especially well suited for this.

The downside is that the heavy battery pack takes away cargo carrying capacity. Trucks are weight-limited to reduce damage to roads.

Regulations on larger trucks still aren't nearly as strict as they are for smaller (pickup) trucks. I'd be surprised if many of the big trucks are running DPF or urea injection. Although maybe that's just because I see more of the older ones around.

The OTR (over the road) trucks are built on multi-million mile chassis, so they get driven until they can't be repaired any more. I wouldn't doubt that some owner-operators are bypassing the emissions systems, even though those trucks tend to get better mileage. A few years ago, 6 mpg was considered good. Now 8.5 mpg is not uncommon.

> A few years ago, 6 mpg was considered good. Now 8.5 mpg is not uncommon.

Are you serious? That's horrific...

If you think that is bad, you should reconsider your car. A big truck is 3x more efficient than a Prius. Take a look at the numbers and analysis presented by "Why are cars unable to match the efficiency of the 18 wheeler?"

http://arstechnica.com/civis/viewtopic.php?t=41085

On a pounds per mpg basis, the truck is moving 9400 pounds (8.5mpg truck, 80,000 pounds), while a Prius is moving about 67 pounds (60 mpg, 4,000 pounds). If you look at the weight of cargo being moved, the ratios are even more in the truck's favor because it can carry 40,000 pounds, or about half it's weight (the Prius can't even come close).

Most trucks can haul about 48,000 - 50,000 pounds, since typical weight for truck and trailer is about 30,000 - 32,000 pounds. Some lightweight OTR trucks weigh less, and day cabs even less than that. Definitely more fuel efficient than any car. Trains win the grand prize, but they can only run where the rails are obviously.

All new trucks use DEF and burn low-sulfur diesel since California requires it. That has been the case for at least 10 years, if not more. The only trucks on the road that do not are older trucks and some "gliders" (new chassis and body with an overhauled engine that is older and doesn't have to meet the regulations). The vast majority of big trucks run cleaner than cars or pickups. By the way, trucking is one of the most highly regulated industries.

Trucks often have associated warehouses or depots that could support centralized battery charging facilities. For cars you are lucky if the owner has a garage that can fit a car.

You just argued that it would make more sense for cars to have replaceable batteries than trucks (which I agree with, and contrary to castratikron): we can count on trucks to have specialized charging facilities, but there are car owners who can only park on city streets or other places, who would be well-served by having battery-swap stations (a la gas stations) rather than home-charging.

Battery swapping with your self is a lot easier. You don't have to account for wear and tear other than just replacing batteries when they bust.

But if I go to a "battery swap" location I'm giving up my new battery and might get a dud. You can set up a business model that solves the problem. For example, use the propane tank model, where you put a deposit down to get the first one, and the customer is always entitled to a swap. And the company always owns the tanks/batteries. But that's an expensive business. These battery packs are big assets currently.

It's easier to just have two or three owned by a truck company who can swap themselves.

> Just because trucks don't need to have a down time for sleeping like a car with a single owner does?

That, and trucks generally go back to depots regularly to load/unload/etc… Even more so if you're swapping tractors around cities, you'd have swapping depots for that purpose.

Because it's far easier to keep all batteries in one location and have short haul trucks do a round trip, dropping off a flat battery in exchange for a fresh one. Very little logistics involved in keeping a bunch of stations stocked.

For some local fleet jobs you can probably put batteries in the trailers (if the cargo is consistently not super heavy).

That requires special trailers and tractors rather than just electrical tractors able to handle any standard trailer.

It also requires much heavier and "non-standard" coupling between tractor and trailer since the trailer now needs to power the tractor rather than the reverse (and needs send significantly more power over the link)

And? Note that I didn't propose it as the likely universal future, just as a potential way to do battery swaps.

> And?

And that means much larger upfront costs for debatable benefits.

I'm no truck expert but that shouldn't be that big of a problem. There are already power cables between trucks and trailers [1]. Thing is to just make a thicker one.

Weight is also no problem as 500kg of batteries is nothing compared to 20 tones of a trailer.

1. https://en.wikipedia.org/wiki/ISO_standards_for_trailer_conn...

> There are already power cables between trucks and trailers [1].

There are power cables but they're used to power the trailer from the tractor rather than the other way around, they're mostly controlling trailer devices (lamps, brakes, etc…) and the general power ones are small potatoes to power cooling (refrigerated trailers) or lifts, not full-blown truck engines.

> Thing is to just make a thicker one.

Well yeah as I noted with that "solution" you need much heavier coupling than the standard ones (and reversed power), so you get to throw all existing tractors and trailers in the trash, rather than just replacing the tractors and keeping all existing trailers.

Reply on news.ycombinator.com