Comment by aurizon | Hacker News Reader

Comment by aurizon | Hacker News Reader

I can see a small niche for hybrids, a small, constant speed engine coupled to a charger to get you past dead spots with no chargers, but the handwriting is on the wall for IC passenger vehicles, and possibly for long haul trucks. While it is true that gas/diesel has a higher energy per tank as well as a faster tank 'fill' time, this does not make up for the far higher cost per mile for the liquid fuels, AND the complexity of thousands of small parts threshing and wearing away. Electric motors are routinely made to run for 100,000 hours and upwards, because they have rotary bearings and only torque to contend with versus the 2500 rpm of IC engines with bearing impact bangs of the IC engine many times per revolution, and the timing belts, and the tappets hammering and the valves burning away, and the muffler and pollution control gizmos rotting and crumbling away. And brakes, with regenerative braking (which wears nothing) we have already seen brake linings on Teslas and others hit 500,000 miles - more? I can see an era of polyurethane(PU) tires also good for 500,000 miles. They cost more, but they run more and are a lot tougher against road damage than rubber. Sure, any fool can burn rubber and jam on the brakes and, in effect, burn $$ to kill them faster, but I am betting that regen braking as well as more AI in the control box that has the potential to avoid almost all friction based braking, because that AI knows your route (mostly - from experience), when to slow with regen for the turns and curves. The moving hand writes, pauses, points it's thumbs down, and moves on. IC engines are in a downwards race to nowhere.

It looks like there is no lithium shortage at all. Cobalt looks like a scarcer element, which adds cost, but electrode design is improving almost monthly and less cobalt is needed. In addition, cobalt is a recyclable material and this will soon be almost 100% captured for re-use, as the growing shortage drives the reward for recycling it.

> Electric motors are routinely made to run for 100,000 hours and upwards, because they have rotary bearings and only torque to contend with versus the 2500 rpm of IC engines with bearing impact bangs of the IC engine many times per revolution, and the timing belts, and the tappets hammering and the valves burning away, and the muffler and pollution control gizmos rotting and crumbling away.

This is why the series hybrids don't really make sense. If you have to add an engine to generate electricity then it needs a fuel tank, a cooling system, an exhaust system, etc. By the time you add all of that stuff, you might as well just use that cost and weight to put in a bigger battery.

There is no technical reason you can't use an arbitrarily large battery to get arbitrarily long range, it's just that the incremental cost exceeds the incremental benefit for most people, so the current EVs are targeting the much larger number of people who don't actually need that much range. They're also supply constrained on battery production right now, so targeting the niche that requires a very large battery doesn't make sense yet.

This is somewhat what I would expect to eventually see out of a pickup or something that competes with a Chevy Suburban. You have a large vehicle, so plenty of room for batteries in the floor, which you also need to get reasonable range when transporting heavy loads. But then if you're not transporting a heavy load, the same batteries provide much more range than a vehicle which is trying to be spry and sporty.

I think battery tech needs to be much cheaper for it to really answer peoples’ needs. But I do see the situations you’re describing. A half ton truck can afford a pretty hefty battery pack, weight wise. Budget wise it gets pricy quickly. I wonder what sort of battery could be afforded in a larger chassis that’d normally go for 90k, though.

> I think battery tech needs to be much cheaper for it to really answer peoples’ needs.

Yes, absolutely, which is what's happening. Lithium battery prices have been falling for years. The price today is too high for a competitive light truck. The price in four or five years time, however?

Sadly, hybrids make sense to the degree that batteries don't. Although an electric motor and its rudimentary cooling system are trivial compared to a combustion engine and it's attendant systems, it starts to make sense when you consider that 1 gallon of gasoline buys you the energy available from a ~40 kWh battery.

Heck, battery electrics arent' even strictly dominant over hydrogen electrics. Hydrogen makes a lot of sense in some applications, what does it say about batteries if people are willing to go to the hassle of developing fuel cells just to get around chemical batteries?

I think they trye to get the density and fast fill ability of a fluid system, but Hydrogen is an economic failure. Hydrogen is so light that it takes a huge strong tank if compressed and if liquid a huge cooled dewar tank. Hydrogen can be made to work in special cases, not for workaday driving

Why not have the standard 400 km battery pack in the car, and another auxiliary 400 km battery pack that one could place in the trunk, on the roof, on the backseat floor, in the frunk, etc, only when needed?

Thing is heavy, you'll need a crane in the garage.

Ecars already have cooling systems, etc. The myth that ecars are more simple is just that. A myth.

Well, ecars ARE simpler, mechanically. IC cars drive the A/C from a pulley on the motor. This means there is a path for high pressure refrigerant gases to the atmosphere. In variably in 2-3 years you lose gas == $$ for the dealers. ecars use a sealed system, like a home refrigeration unit = no gas leakage path. There is another cooling path for the batteries to get rid of the charge/discharge heat, this is another fully sealed fluid circulating system that only leaks in some accident

As someone who owns a long range EV I don't see trucking/towing going away soonish. Even towing marginal 6-8k loads we see ~11mpg in our efficient truck(v6 turbodiesel). The energy density just isn't there for 100mi+ trips.

That said I'd kill for a diesel electric truck, love the torque and smoothness of our EV.

Tesla’s new Raven motors and a more energy dense pack based off the 2170 cells in the Model 3 make this use case within reach. Their Semi is dragging a 80k tractor trailer load (concrete blocks) around to demonstrate the high end working.

Disclaimer: I occasionally tow ~2500lbs with my Model S. Works very well, no Auotpilot though while towing.

How much does the range degrade when towing?

I lose 40-50% of range, depending on the weight and aerodynamic profile of the load; went with a 100D to mitigate the reduced towing range.

I wonder how much range you could get back with a trailer equipped with regenerative breaking? Or if it would be too much for the battery to cope with?

The vehicle recovers the collective momentum of both it and the trailer when braking.

The trailer is unbreaked? That seems rather dangerous!

Only need trailer brakes if the gross weight is above 3000lbs in my jurisdiction. I also keep the speed reasonable when towing to prevent jackknifing or oscillation.

I think I implicitly assumed that the 40% reduction in range you mentioned was due to a larger load than it sounds like you are carrying. It would be interesting to see if the car was using regenerative braking less with the increased load. Also the break down of where the extra energy is going (i.e. aero, rolling resistance, hills and acceleration etc). Would depend a lot on the type of driving you are doing, but I would have imagined that extra mass is less of a problem for electric vehicles since there is the opportunity to recover potential energy.

Its the aerodynamics for sure that kill my range and double my per mile energy usage. Petrol tow vehicles have so much more energy density available to them, their aerodynamics are less of an issue.

Still, no problems towing a Waverunner to the beach or an antique sewing machine to a friend’s house from a craigslist find.

Sounds like an opportunity for trailer manufacturers to make aero trailers for electric vehicles...

Indeed!

While I think you're right, I do want to correct you on something.

Class 8 trucks like the Tesla semi have an 80,000 pound total weight, hence the name 'Class 8'. Typically the truck and trailer weighs 32,000 pounds leaving 48,000 pounds for cargo. Average cargo weights are in the 35,000 pound to 45,000 pound range. If the Tesla semi significantly raises the empty weight of the truck it will limit the amount of cargo that can be carried. A load of toys will be nowhere near the weight limit but a load of milk products will easily exceed it.

Some states allow increased Class 8 loads as high as 115,000 pounds, mitigating the weight issue.

My guess is that Tesla will try as hard as possible to match the weight of existing trucks. It is interesting that they haven't released weights, perhaps because they don't yet know or because it is bad news. If it was lighter I imagine Elon would have mentioned it multiple times in tweets.

https://www.teslarati.com/how-much-tesla-semi-truck-battery-...

For metric people: Class N3 (35 tons), some states allow Class N4 (52 tons).

> It is interesting that they haven't released weights, perhaps because they don't yet know or because it is bad news.

I'm guessing the bad news part.

My Half-Ton Silverado Crew Cab's (That's the 4-door smallest full-size pickup) curb weight is 4,942 lbs. The heaviest Tesla Model S' (biggest battery I assume) curb weight is 4,941 lbs.

More weight spent on the cab and trailer is less weight spent on cargo, and money in the trucking industry is driven by how much you can carry (Speed is restricted, hours of driving are restricted, but amount cargo - other than weight - is not).

Definitely makes more sense in the tractor-trailer market, where the additional battery cost will be easier to account for. Doubling the price of a pickup is probably a no-go, so a few more years at least before the pricing gets acceptable there.

My napkin-math calculation suggests that to have an electric pickup capable of replacing our F150, I'd need a battery pack that would capable of pushing a Model S a thousand miles. Definitely within the realm of possibility, but introduces a non-trivial amount of extra cost at current battery pricing, and compounds the hassle of recharging.

So I agree, we are quite a ways off yet from plausibly displacing ICE from pickups. At least in the full size pickups. Seems a bit more plausible in the Colorado/Ranger/Tacoma sized pickups that are less often used for towing.

I may be wrong, but you only need the extra battery capacity when towing. So it's possible that your trailer could be equipped with the extra batteries.

That makes things worse, usually you want to less weight on the trailer. Right now I've got a 7.5k towing capacity, if a pack weighs 2-3k that cuts my towing capacity in half.

Do you typically have things in the bed when towing? Just brainstorming, a removable battery pack that sits in the bed for when you're hauling would save weight when your not hauling.

Is the towing capacity limited by the drivetrain or chassis? If it's drivetrain then I suppose that it does not help to move the batteries to the bed. But if you're chassis limited, then keeping those batteries off the towhook would help, no?

Most pickups reach payload capacity before the tow rating itself is reached. Payload includes everything -- driver, passengers, cargo, anywhere in the truck.

To an extent, putting the batteries in the trailer does make a little more sense since it won't count 1 for 1 against payload (typically about 10-15% of the trailer weight will be on the tongue, for safety).

For some reason I actually got downvoted for saying it in my original comment, but cost is a big consideration for now and why I think we're a ways off yet from full size EV pickups. Takes a big battery pack to tow an open parachute (what it feels like towing a high frontal area trailer ;-)) 300 miles a day. And then it has to be recharged, which can be a problem given that most people take RVs places that don't have great infrastructure.

Yeah, not sure why you were down voted. As an EV and truck owner your comment was pretty on the mark.

Locomotives have been diesel-electric hybrids for decades, so it probably makes a lot of sense for trucking, I agree.

Yeah, I've always been curious if running a diesel motor at optimum RPM offsets the conversions loss.

Locomotives do that because they need to power many wheels, and because they need huge torque at zero speed to get started. Trying to do that with a very large clutch is painful. (There are locomotive-sized clutches for some smaller locomotives, and British Rail was once into that approach, but it's obsolete.) Modern locomotives run the motors as synchronous AC servomotors, locking all the wheels together in software.

Freightliner has an electric semitruck.[1] So do MAN, Mercedes, Mitsubishi, etc.

[1] https://www.youtube.com/watch?v=qwI4Wt5Av3k

> diesel electric truck

Ford my actually provide you with that. They showed a Ford Transit in Amsterdam last week. It has 75kW battery with 200km range, but you can order a diesel powered range extender for it.

I think Tesla should partner up with a company that could add a range extender to the frunk.

The entire design of Tesla's vehicles is based around no firewall, no exhaust system. They would have to put that all back in if they added an ICE.

Won't it be inefficient to convert engine displacement - > charge - > vehicle displacement again?

I wonder if it is instead possible to have a universal battery installer. A universal battery pack that serves the same purpose as what you suggest, the size of a small engine + petrol tank.

One that is cross compatible with all electric cars. (the hard part) maybe it can be a section in the boot itself. So when not in use, it is simply boot space. (will be easier to be universally. Compatible too) as long as there is a power in the boot.

You pick one up from a store and as long you return it to another store inside of a few hours, you are only charged the cost of electricity + battery rental.

The trouble with this is that the amount of battery it takes to be equivalent to a tank of gasoline weighs on the order of a thousand pounds. They only get away with it as part of the car because the electric motor is light (~70 pounds compared to ~400 for a gasoline engine) and you also eliminate the fuel tank, transmission, exhaust system, etc.

The battery is also large enough that the shape is dictated by the shape of the car. Making them easily swappable wouldn't be easy.

The more likely solution is to just increase the number of charging points, and then have models specifically designed with larger batteries for people who need longer ranges.

The existing ranges are already sufficient for typical usage. Most people rarely drive more than 300 miles in one day, and almost never drive more than 600 miles in one day, so we're already at the point that on 99% of days you don't have to care about it at all and then on the occasional road trip you have to stop for an hour out of every five to have a meal and charge the vehicle.

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