'Supercharger on wheels' brings fast charging to you | Hacker News Reader

'Supercharger on wheels' brings fast charging to you

electrek.co

27 pointsrmason45 comments

Porsche did it a few years ago.

https://newsroom.porsche.com/en/2020/company/porsche-high-po...

Here is an ev influencer talking a bit about it: https://m.youtube.com/watch?v=a6lmTJiNTJc

I wonder why no one just has a pickup with a generator in the back and drives around to help EV’s that ran out of batteries.

Actually you could hang around overcrowded charging stations and make some good money. People in a hurry would pay a premium.

You would need a pretty big generator though. But an interesting idea.

I remember I saw something similar in Ukraine when the war stared, a Tesla drivers was photographed fleeing the country towing a generator.

https://www.reddit.com/r/ukraine/comments/zxk623/in_kyiv_the...

That's what breakdown companies (like the AA and RAC in the UK) do. It's slow enough that you'd only want to use it to get just enough juice to get to a proper charger, though - they use 3.5kW or 5kW chargers: https://www.rac.co.uk/drive/news/rac-news/rac-begins-rolling....

I'd imagine it's way less efficient and way more polluting than using the national grid, too.

I doesn’t happen nearly enough to be worth the effort. Electricity is cheap, and these mobile services are only worth it if they can charge a premium. And they can only charge a premium when a car is literally stranded. And that happens infrequently enough that you may as well just use a tow, which is readily available.

Well a generator would just make the power needlessly expensive. Presumably the whole point of such an operation would be to use cheap power and sell it at a premium.

That's the general idea behind series plug-in hybrid electric vehicles (PHEVs).

..Gasoline engine acts solely as a generator to recharge the battery, but can't mechanically power the wheels (known as "series hybrids"). Example: BMW i3..

https://www.caranddriver.com/features/a45483659/plug-in-hybr...

The fossil i3 is notoriously much worse than the electric one. Heavier, less reliable, more expensive to run. It only makes sense if you don’t have a dense fast charger network where you live and you somehow decide to use this car to drive long distances.

I might use this in an emergency but otherwise this seems spectacularly inefficient and unappealing.

I was thinking it might be a truck mounted diesel generator. Instead it appears to be an even bigger battery on wheels. Must draw a massive amount of electricity to charge it up. Probably need to park it next to an electricity substation.

Porsche has a similar solution for race tracks and remote press events. A 2.1 MWh trailer that can dispense power at 3.2 MW.

I think they are doing some clever things with solar to keep it charged (basically constant trickle charge with whatever they can generate), but the array might be pretty massive.

https://www.porsche.com/stories/mobility/how-does-a-mobile-c...

What is the actual difficulty of charging at higher power? Is it getting energy to the charger? The charging device itself?

Even as a non-EV-maximalist, I find it mind-boggling that we pump oil out in a few places in the world, ship it to turn it into gasoline, then ship it to millions of pre-placed fuel tanks and pumps around the world, and it all just works. Whereas even though all these places have electric power too, they can't charge EVs.

It's the hardware required to output a huge volume of electricity into the battery in a short amount of time.

Getting the power to the charger is trivial.

But what is it then, beyond a thick copper cable? An expensive transformer-rectifier? High-power electronics?

If I look at a petrol pump, I understand what makes it bulky. What makes a high power car charger bulky and expensive?

It converts from AC to DC and then has to work with the car to figure out at what rate to send power. You can't just go full throttle or the battery would start a fire (simplification).

A gallon of diesel, which you can easily carry, has about 40 kWh of (admittedly thermal) energy. You can pour it into a tank in a few seconds.

Edit: if it takes 10 seconds per gallon, that's 14.4 megawatts. Quite a lot. For instance, this massive wind turbine is rated 14 MW:

https://www.siemensgamesa.com/products-and-services/offshore...

Yeah, I've heard it's hard/impossible to put together a cable to transfer that much energy; in that context ofc. It's substation-tier equipment.

Battery-swapping may be the way.

It’s just growing pains.

Electric cars are trivial to charge at home because they get hours to charge every day. However on a road trip people want to dump as much energy as quickly as possible which has meant a rapid evolution of what cars/cabling/chargers/grid can handle and what chargers can supply. In 20 years this will all be boring infrastructure just like gas stations, until then it’s going to be a bumpy ride.

Charging an EV is straightforward if you have a home parking spot. However, "According to the 2017 American Housing Survey, 66% of all occupied housing units in the United States had a garage or carport."

For those living in big cities and relying on street parking, EVs are still less practical. I envision a service where you leave your car parked on the street and schedule a mobile charger through an app to come and charge it while you're away.

Add driveway to garage or carport, but I get your point.

Individuals can’t install them, but cities or parking garages can. Level 1 or 2 chargers down a city street makes more sense the more EV adoption increases.

Right now only 1% of cars on the road are EV’s, but EV’s and plug in hybrids are 18% of new car sales. Even if adoption stalls we will still build a lot more EV infrastructure, which then makes EV’s more attractive.

Pretty sure the real issue is safety. Obviously you want to avoid exposed hot contacts and arcing, but also thermal safety is a pretty big deal. Addressing that increases cost, so companies don't want to do it unless there's enough proven demand at that location to pay it back quickly. Same problem as internet access or mail delivery to rural areas, and the same solution suggests itself.

This problem could also be solved by using battery swap stations, where batteries charge much slower but the change is nearly instant. It's already a standard for electric motorbikes in Asia, especially for delivery folks.

I tried a system like this about 15 years ago, and it was unweildy:

https://en.wikipedia.org/wiki/Better_Place_(company)

China is propelling its electric truck market by embracing battery swapping.

In 2022, China sold 36,000 electric trucks, 91% of the global total..support for battery swapping is playing a key role.

With plug-in charging, it usually takes 40 minutes with DC fast charging or several hours via regular charging to recharge an electric truck. In contrast, battery swapping only takes 3–6 minutes.

https://theicct.org/china-is-propelling-its-electric-truck-m...

The NIO car company sells cars with swappable batteries and has built battery swap stations in Netherlands, Germany, Denmark, Norway and Sweden. The swap action looks slow and very particular still to be honest, but there's probably good reasons behind it (including not wanting actuators on the car itself): https://www.youtube.com/watch?v=aBdQQxgxDrY

The swap takes six minutes (example https://www.youtube.com/watch?v=VmWL1hZQmD0). The swap stations charge the packs to 90%. So swapping in a 100 kWh pack that has been charged to 90 kWh is the equivalent of charging the car at 900 kW.

Nio will start introducing 150 kWh packs in the same physical form factor which they charge to 135 kWh. Swapping one of those in would be the equivalent of charging at 1.35 megawatts.

Building out the infrastructure just takes time. There's only so much capacity for new builds. Eventually there will be EV chargers everywhere.

North America's infrastructure build out has also been stunted by a dumb EV charging standards war. CCS won the protocol war (CHAdeMO and Tesla's protocol lost) and Tesla's plug has now been standardized as SAE J3400. The future for North America is CCS chargers with the J3400 plug on the end.

Here's an example of that happening now. Same CCS charger that was already there, now with a different plug on the end. They replaced the CHAdeMO plug with a CCS J3400 plug:

https://www.youtube.com/watch?v=Y3-0xRTduPI

Europe's EV infrastructure is further along in part because they sensibly standardized on CCS type 2 Combo a decade ago. And a lot of the rest of the world will use it too:

https://insideevs.com/news/333637/european-ccs-type-2-combo-...

Standardization drove investment and development. All companies could build to a common standard so all brands of charging network, all brands of charger could more easily interoperate with all brands of EV.

It's a shame that car companies couldn't agree on a global plug and a global protocol. But at least CCS will be used by most of the world.

> And a lot of the rest of the world will use it too:

China has its own standard, which probably dwarfs Europe in terms of EVs using it. But it’s not like people are driving much between the two regions.

> China has its own standard

Standards. China is deprecating the GB/T plug and Japan is deprecating the CHAdeMO plug. China and Japan will switch to ChaoJi (aka CHAdeMO 3.0) which has a new plug and protocol changes. It would be better if they just used CCS, even if they want to insist on yet another plug:

https://en.wikipedia.org/wiki/ChaoJi

There's nothing wrong with it on a technical level. It's just dumb to introduce yet more incompatibility when they could harmonize with the rest of the world.

Japan in particular should harmonize with right hand drive countries (which would mean CCS Type 2 Combo).

You want a really crazy idea?

How about a fleet of vehicles that charge EV semi trucks WHILE THEY ARE MOVING. That could reduce the needed size of the tractor battery and the cost of the whole system.

Downside is it would probably be gasoline-powered.

Less radically, you simply tow an additional trailer that is a power generator/range extender. It can be a trailer of batteries that you simply swap at a swap station rather than wait to recharge, and you don't need some whacko battery swap scheme.

Honestly I think that should work for any EV, a range extending trailer. That way you can buy a 150-200 mile max range car for your daily stuff, and just rent/borrow a range extending trailer for longer trips.

i believe that's just a plug in hybrid

> that's just a plug in hybrid

To the extent an aircraft carrier is just an airstrip.

Just run regular shuttles between points A and B. Each participating truck has a connector on the front and one on the back, so that together they only occupy a single traffic lane.

Any visual resemblances to a train are strickly coincidental.

Maybe we could even put a cheap wire overhead to supply electricity, that way we don't need heavy and expensive batteries.

Imagine if instead of roads we have some sort of low friction surface that also controls the direction of the vehicle. Some sort of metal rail. Then the vehicles could be larger, open to the public, and follow a set schedule!

And they could have additional rails that branch off the road every few miles and run directly to a set of various businesses. The system would just need a way to allow individual trucks to leave and return as deliveries are made.

I'll do you one better, use magnetic levitation so there's no friction at all. And build it in a vacuum pipe, so there's no air resistance either.

I wonder why nobody else has thought of that yet? Such a mystery.

Trolley buses work this way. Sort of a halfway house between buses and trams.

Edison Motors has built diesel-electric truck that operates essentially like a diesel-electric locomotive. Last I read it got whatever certifications are needed and is now 100% street legal. They intend to also build retrofits for existing semi trucks.

https://www.edisonmotors.ca/

Just out overhead wires over the interstate and the trucks can charge/draw juice from the grid that way. Bus routes in many countries still use that (Seattle and SF for the states, probably some others, and of course trains in Europe and Asia.

Trains in the USA mostly use diesel turbines to generate electricity that is then used to move the train. You could do the same with a truck, although I don’t think it would pay off the same as it does in trains.

Energy pricing arbitrage on wheels? :)

Excellent idea. Might pay for itself in a hurry.

Yep. Get yourself some low quality/crap land that's not too far from a population center with insane electricity pricing and turn it into a solar panel farm (or wind farm, etc).

Regulations often seem to block new entrants from doing that and supplying the grid... but stuffing all of that energy into something portable which can directly top up or recharge consumer vehicles seems like a cool idea.

Hopefully it works out for them such that they can scale up then open up further options for themselves. :)

Would not want to be anywhere near the first highway accident involving one of these.

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