In many ways, an electric car would make an ideal city car. The lack of car-generated pollution, both noise and emissions, has the biggest benefit in a dense city environment, and the trips tend to be shorter, well within most EVs’ range. Yet for most urban apartment dwellers with street parking, there’s just no good way to charge an EV. I think I have an idea that can help.

First, let me make clear the problem I want to address: the electric car charging infrastructure sucks. Most current EV owners get around this by having houses with driveways that allow for overnight charging of their cars. For daily commutes and normal driving, they can usually get by without having to hunt down an EV charging station.

For the millions and millions of people in cities all over the world that live in dense, urban areas, in apartments, and who park their cars on the street, home charging is simply not an option. Because the charging infrastructure in most cities is still so rudimentary, that also means that for these millions of street-parkers, electric cars are simply not an option, even if every other aspect of their lives would make such a car ideal.

Sure, maybe one day there will be a charging point at every parking meter and street side parking place. But nobody has even started any large-scale infrastructure project like that, and if they did, it would take years to finish.

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As much as I love the idea of battery swapping, nobody is close on getting that going on any scale, and while Tesla has had some patents surface regarding that, no major carmaker seems all that interested in pulling the trigger on that.

The public infrastructure for street side charging is not there, and the major carmakers don’t seem to give a shit. We’re on our own here. If we can’t charge EVs on the street, what can we do?

We can bring the charging to the cars.

What I’m thinking is that we need a solution that would work with what’s available in the very near future, and won’t require waiting on utility companies or carmakers to agree to help out. The way to do that is with autonomous mobile battery tender vehicles that come to the cars, instead of taking the cars to the chargers.

Now, there’s some pretty major logistical hurdles to leap for this to work. The cars that need help are ones parallel parked on the side of busy city streets, and any mobile battery can’t block traffic or just hope to find a space close enough to the EV that needs charging—somehow, it has to do its business out of the way of normal traffic. This is especially important since the time to charge could potentially take hours.

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Also, the system can’t require extensive modifications to the EV itself. This needs to be something that can work for any EV sold today.

The idea I had solves these issues, and, while it may seem sort of goofy, I think actually has potential to be a viable solution. It’s an autonomous driving battery, essentially, but one that has the ability to raise up and over a given EV, allowing it to occupy the same ground space as the parked car, and not blocking traffic at all.

Here’s what the battery tender vehicle I’m thinking of is like:

Fundamentally, it’s a low-speed (say, 35 or 40 MPH tops, good enough for inside a city) electric autonomous flatbed truck. The entire middle section is a battery. I’m thinking it should have a capacity of at least the equivalent of two Tesla Model S 85 kWh battery packs, which would mean it would weigh about 2400 lbs.

The front section contains autonomous electronics and sensors, drive motors, cooling systems and so on for the vehicle and its related equipment. The rear section contains batteries for use by the tender’s own functions, though I suspect it should be able to tap the main battery too, if needed.

The chassis has some ability to extend its length by extending the rear section backwards, and under at center section of the tender is a (maybe hydraulic) lifting unit and wheeled base. Here’s a little animation of how the tender works:

Just pretend that old Golf is a cool new EV

It’s a six-step process:

  • 1. The tender approaches the EV that needs charging. The EV is equipped with an add-on cable that relocates the charging point to the roof, and is secured via magnets (more on this soon).
  • 2. The tender parks next to the EV, then drops its lifting support wheels and extends the safety arms to under the car.
  • 3. The tender’s lifting mechanism raises the tender into position, just above the car’s roof.
  • 4. The lift support assembly moves the raised tender over the car on its wheels, which slide under the car. The safety arms are under the car in position to utilize the EV as a counterweight to prevent any external forces from tipping the raised tender.
  • 5. The raised tender connects to the roof-mounted charging port with a compatible port on its belly, and begins to charge the car, remaining as long as needed to get the car sufficiently charged.
  • 6. Once charged, the tender unplugs, the lift mechanism moves it back next to the car, the tender drops back to its main wheels on the ground, lifts the lifting wheels, and leaves, either to charge more cars or return to base for recharging.

It seems weird, I know, but all of this should be quite technically feasible. The mass of the battery is always over the wheels, so even if it looks scary, it should be quite stable, and just in case, the two arms that are deployed under the car should be able to keep the tender from tipping, even if, say, an escaped chimp decides to climb on it.

The roof-mounted charging port would be accomplished with a simple cable. Whatever company is running these tenders would have a variety of molded rubber cables made for most major EVs, and these cables would plug into the car’s existing charge port, and run up the A or C pillar to the roof, where the extended charge port would be held to the roof via magnets, or suction or other means for non-metallic roofs.

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The tender company would be operated as a subscription service; a client would sign up, and would schedule a one-time first visit where a tender would meet them at their car, and an employee would show up as well. The employee would fit the owner’s car with the roof-mounted charge port extender, and would do a test fit of the tender vehicle with the owner’s EV.

All parameters about the owner’s car—what height the tender needs to raise to, does the rear need to be extended, where the safety arms need to reach, etc. would be stored in that client’s file, so when the tender finds the clients car, it knows exactly how to configure itself.

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A device sending GPS data and state of charge would be plugged into the car’s OBD port (kinda like those things insurance companies are using now) and would communicate with the company about where the car is, and if it needs to be charged. The owner can set up a recurring recharge, or can set a battery percentage level that triggers a tender to be sent to the car, which it finds from the OBD unit sending the car’s GPS location.

The company that runs the autonomous battery tenders would have some sort of physical base in the city, where the fleet of tenders would return to be charged, serviced, and, likely, have the graffiti scrubbed off of them.

Our weekend kook Alex came up with a little mascot for me

These mobile battery chargers would allow many, many apartment-dwelling, street-parking people in big, dense cities like New York, Tokyo, Rome, Berlin, Shanghai, Seoul, and so on to viably own an electric car. Even less dense cities that still have massive populations of renters without driveway parking, like Los Angeles, could benefit from these battery tenders as well.

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All this without having to wait for infrastructure to be built, or carmakers to figure out how the hell they want to handle battery swapping.

Plus, these things will be fun to watch raise up and crab into position over a car. You can tell kids that’s how baby cars get made, if you want.

As always, people who know how to do business stuff to make lots of money, you know how to contact me.