A Deep Drive Deep Dive Into A Twin-Rotor Motor

December 9, 2025 by Tyler August 45 Comments

Compromise is key to keeping a team humming along. Say one person wants an inrunner electric motor, and the other prefers outrunner. What to do? Well, if you work at [Deep Drive], the compromise position is a dual-rotor setup that they claim can be up to 20% more efficient than standard designs. In a recent video, [Ziroth] provides a deep dive into Deep Drive’s Twin-Rotor Motor.

This is specifically a radial flux permanent magnet motor, like most used in electric vehicles today — and don’t let talk of inrunners and outrunners fool you, that’s the size of motor we’re talking about here. This has been done before with axial flux motors, but it’s a new concept for team radial. As the names imply, the difference is the direction the magnetic field is orientated: axial flux motors have all the magnetism oriented along the axis, which leads to the short wide profile that inspired the nickname “pancake motors”. For various reasons, you’re more likely to see those on a PCB than in an electric car.

In a radial flux motor, the flux goes out the radius, so the coils and magnets are aligned around the shaft of the motor. Usually, the coils are held by an iron armature that directs their magnetic flux inwards (or outwards) at the permanent magnets in the rotor, but not here. By deleting the metal armature from their design and putting magnets on both sides of the stator coil, Deep Drive claims to have built a motor that is lighter and provides more torque, while also being more energy-efficient.

Of course you can’t use magnet wire if your coil is self-supporting, so instead they’re using hefty chunks of copper that could moonlight as busbars. In spite of needing magnets on both inner and outer rotors, the company says they require no more rare-earths than their competitors. We’re not sure if that is true for the copper content, though. To make the torque, those windings are beefy.

Still, its inspiring to see engineers continue to innovate in a space that many would have written off as fully-optimized. We look forward to seeing these motors in upcoming electric cars, but more than that, hope they sell a smaller unit for an air compressor so after going on a Deep Drive deep dive we can inflate our rubber raft with their twin rotor motor boater bloater. If it works as well as advertised, we might have to become twin-rotor motor boater bloater gloaters!

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Open Safety In The Auto Business: Renault Shares Its Battery Fire Suppression Tech

March 7, 2025 by Jenny List 31 Comments

As consumers worldwide slowly make the switch from internal combustion vehicles to lower-carbon equivalents, a few concerns have appeared about electric vehicles. Range anxiety is ebbing away as batteries become bigger and chargers become more frequent, but a few well-publicized incidents have raised worries over fire safety.

Lithium-ion batteries can ignite in the wrong circumstances, and when they do so they are extremely difficult to extinguish. Renault has a solution, and in a rare moment for the car industry, they are sharing it freely for all manufacturers to use.

The innovation in question is their Fireman Access Port, a standardized means for a fire crew to connect up their hoses directly to the battery pack and attack the fire at its source. An opening is covered by an adhesive disk designed to protect the cells, but breaks under a jet of high-pressure water. Thermal runaway can then be halted much more easily.

The licensing terms not only allow use of the access port itself, but also require any enhancements be shared with the rest of the community of automakers using the system. This was the part which caught our interest, because even if it doesn’t come from the same place as the licences we’re used to, it sounds a lot like open source to us.

Oddly, this is not the first time Renault have open-sourced their technology, in the past they’ve shared an entire car.

2022: As The Hardware World Turns

January 3, 2023 by Tom Nardi 30 Comments

Well folks, we made it through another one. While it would be a stretch to call 2022 a good year for those of us in the hacking and making community, the light at the end of the tunnel does seem decidedly brighter now than it did this time 365 days ago. It might even be safe to show some legitimate optimism for the year ahead, but then again I was counting on my Tesla stocks to be a long-term investment, so what the hell do I know about predicting the future.

Eh, my kids probably weren’t going to college anyway.

Thankfully hindsight always affords us a bit of wisdom, deservedly or otherwise. Now that 2022 is officially in the rearview mirror, it’s a good time to look back on the highs (and lows) of the last twelve months. Good or bad, these are the stories that will stick out in our collective minds when we think back on this period of our lives.

Oh sure, some might wish they could take the Men in Black route and forget these last few years ever happened, but it doesn’t work that way. In fact, given the tumultuous times we’re currently living in, it seems more likely than not that at some point we’ll find ourselves having to explain the whole thing to some future generation as they stare up at us wide-eyed around a roaring fire. Though with the way this timeline is going, the source of said fire might be the smoldering remains of an overturned urban assault robot that you just destroyed.

So while it’s still fresh in our minds, and before 2023 has a chance to impose any new disasters on us, let’s take a trip back through some of the biggest stories and themes of the last year.

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We Can’t Switch To Electric Cars Until We Get More Copper

August 31, 2022 by Lewin Day 205 Comments

Reducing emissions from human activity requires a great deal of effort in many different sectors. When it comes to land transport, the idea is generally to eliminate vehicles powered by combustion engines and replace them with electric vehicles instead. At a glance, the job is simple enough. We know how to build EVs, and the technology is getting to the point where they’re capable of replacing traditional vehicles in many applications.

Of course, the reality is not so simple. To understand the problem of converting transportation to electric drive en masse, you have to take a look at the big numbers. Focus in on the metrics of copper, and you’ll find the story is a concerning one.

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Recycling Will Be Key To The Electric Vehicle Future

July 15, 2021 by Lewin Day 114 Comments

Electric vehicles have become a mainstay in the global automotive marketplace, taking on their gasoline rivals and steadily chewing out their own slice of market share, year after year. Government mandates to end the sale of polluting internal combustion engine vehicles and subsidies on cleaner cars promise to conspire to create an electric vehicle boom.

The result should be much cleaner air, as generating electricity in even the dirtiest power plants is far cleaner and more efficient than millions of individual engines puttering about the place. However, if the electric car is to reign supreme, they’ll need to be built in ever greater numbers. To do that is going to take huge amounts of certain materials that can be expensive and sometimes in very limited supply. Thus, to help support the EV boom, recycling of these materials may come to play a very important role.

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Hackaday Podcast 080: Trucks On A Wire, Seeing Sounds, Flightless Drone, And TEA Laser Strike

August 14, 2020 by Mike Szczys 1 Comment

Hackaday editors Elliot Williams and Mike Szczys flip through the index of great hacks. This week we learn of a co-existence attack on WiFi and Bluetooth radios called Spectra. The craftsmanship in a pneumatic drone is so awesome we don’t care that it doesn’t fly. Building a powerful TEA laser is partly a lesson in capacitor design. And join us in geeking out at the prospect of big rigs getting their juice from miles of overhead wires.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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Choosing The Right Battery For Your Electric Vehicle Build

January 7, 2020 by Lewin Day 43 Comments

Many a hacker has looked at their scooter, bike, or skateboard, and decided that it would be even better if only it had a motor on it. Setting out to electrify one’s personal transport can be an exciting and productive journey, and one that promises to teach many lessons about mechanical and electronic engineering. Fundamentally, the key to any build is the battery, which has the utmost say in terms of your vehicle’s performance and range. To help out, we’ve prepared a useful guide on selecting the right battery for your needs.

One Chemistry To Rule Them All

Batteries come in all shapes and sizes, and a variety of different chemistries that all have their own unique properties and applications. When it comes to small electric vehicles, it’s desirable to have a battery with a low weight, compact size, plenty of current delivery for quick acceleration, and high capacity for long range.

30 years ago, options were limited to lead acid, nickel cadmium, and nickel metal hydride batteries. These were heavy, with low current output, poor capacity, and incredibly slow charge times. Thankfully, lithium polymer batteries have come along in the meantime and are more capable across the board. Offering huge discharge rates, fast charging, light weight and high capacity, they’re undeniably the ultimate choice for a high performance electric vehicle. They’re also wildly popular, and thus cheap, too!

There are some hangups, however. It’s important to keep all the cells in a pack at the same voltage in order to avoid cells back-charging each other. This can cause damage to the pack, or even explosions or fire. Maintaining the battery voltages to avoid this is called “balancing”. It can be handled in various ways, depending on the exact style of battery you’re using, as we’ll cover later.

Additionally, lithium batteries do not like being over-discharged. As a rule of thumb, it’s a good idea not to let your batteries drop below 3.0 V per cell. Failure to keep this in check can lead to ruining a pack, hurting its maximum capacity and ability to deliver current.

There are thankfully ways around these issues, and which ones you use depends on the battery you choose for your application. Continue reading “Choosing The Right Battery For Your Electric Vehicle Build” →