Hackaday Prize Entry: Building A Car, From Scratch, Out Of Foam

Want an impressive example of what a few people can do in a garage? How about building an electric car, from scratch, starting with a gigantic chunk of foam?

The Luka EV from [MW Motors] had a few project aims: it should be all-electric, naturally, with a top speed of 130km/h or 80mph. It should have a range of over 300km, and it should look good. That last line item is tricky; it’s not too hard to build an electric car, but to make one look good is a challenge.

The design of the car actually started out as a digital file. A large block of foam was acquired and carefully carved into the desired shape. This foam is covered fiberglass, and parts are pulled off this fiberglass mold. This is a great way to do low-volume production – once the molds are complete, it’s a relatively simple matter to build another body for a second Luka EV.

With all the lights, accessories, windows, and trim installed, it’s time to put this body on a chassis. This was welded out of square tube and serves as a test rig that can be independent of the mess of fiberglass. In the chassis are batteries, suspension, motor controllers, and wheels loaded up with hub motors. It works well, even with one motor.

There’s a lot more to this project, including a great guide on building a road legal car in the UK. The team isn’t based in the UK, but it’s a much more friendly environment for ‘small series’ vehicles. The requirements are easy to meet – “have a horn”, for example – but there are a lot of them.

Already the car is beautiful, and that’s just with it sitting on a trailer. We can’t wait to see this thing hit the road.


The 2015 Hackaday Prize is sponsored by:

Odd-Looking Mini EV Yard Tractor Is Made From Plywood And Bike Parts

Mini EV Tractor[Ian] likes to build small Electric Vehicles and his most unique project is certainly this yard tractor. During the design phase of the project [Ian] came up with a few requirements to ensure that this vehicle would be useful around the house. First, it had to be maneuverable in tight spaces. This was accomplished by the short wheel base and small diameter front-steering wheels. Next, it had to get great traction as leaving torn-up grass around the yard was not going to cut the mustard. Four mountain bike drive wheels used in the rear double the traction while at the same time distributing the friction over twice the surface area of the grass. To increase the traction even more, the rider’s seating position was intentionally put directly over the rear wheels.

The frame was kept simple by using plywood as structural members. Two 40Ah 12v batteries are set low between the front and rear axles and power the 4 DC drive motors. The motors are connected to the axle by means of sprockets and chains which results in a 36:1 reduction. That’s a large gear reduction and limits the tractor to a top speed of 12 km/h (7.5 mph). Bike tires front and rear were used because they are easily available and are super low-cost. And of course, a tractor wouldn’t be complete without a trailer hitch to tow around plants, rocks, wood or any other general yard debris.

[Ian] makes plans for his mini EV tractor available on his website. If your kid is envious of this electric tractor, maybe you can make him one of these

 

Electric Bubblegum Board

The Mini Maker Faire in Atlanta was packed with exciting builds and devices, but [Andrew’s] Electric Bubblegum Boards stood out from the rest, winning the Editor’s Choice Award. His boards first emerged on Endless Sphere earlier this summer, with the goal of hitting all the usual e-skateboard offerings of speed, range, and weight while dramatically cutting the cost of materials.

At just over 12 pounds, the boards are lightweight and fairly compact, but have enough LiFePO4’s fitted to the bottom to carry a rider 10 miles on a single charge. A Wii Nunchuck controls throttle, cruise control, and a “boost” setting for bursts of speed. The best feature of this e-skateboard, however, is the use of 3D-printed parts. The ABS components not only help facilitate the prototyping process, but also permit a range of customization options. Riders can reprint parts as necessary, or if they want to just change things up.

[Andrew’s] board is nearing the 11th hour over at his Kickstarter page, so swing by to see a production video made for potential backers, or stick around after the break for some quick progress and demo videos.

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Electric Longboard Roundup

ev longboards everywhere!

Everybody and their grandmother is longboarding electric-style these days: here are some of the most recent developments in the world of kickless cruising.

First up, [comsa42] has punched up an excellent step-by-step visual guide for first-time EV hopefuls, detailing the basics of a battery-powered longboard setup and thoroughly explaining the particulars behind component choices. His build is relatively straightforward: combine a board with a low(ish) kV outrunner motor, some LiPo batteries, an ESC (Electronic Speed Controller), a transmitter/receiver, and a few custom parts for gearing and mounting. This build should be commended not only for its simplicity but also for its frugality: [comsa42] estimates a final cost of around only $300, which is a staggering difference from commercial alternatives such as the Boosted Board and newcomer Marbel.

[comsa42’s] other significant contribution is a low-key and low-cost cover to house the electronics. He simply fiberglassed a small enclosure to protect the expensive internals, then mounted and painted it to blend seamlessly with the rest of the deck. You can find loads of other useful goodies in his guide, including CAD files for the motor mounts and for the wheel assembly.

But wait, there’s more! Stick around after the jump for a few other builds that ditch traditional wheels in favor of a smoother alternative. There’s also a smattering of videos, including comsa42’s] guide overview and some excellent cruising footage of the other board builds doing what they do best.

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A Simple, Overkill, Electric Car

If you’re building an electric car nowadays, you’re probably looking at taking a normal, gas-powered car and replacing the engine and transmission with an electric motor and batteries. [Gahaar] thought this is a rather dumb idea; all the excesses of an internal combustion-powered car, such as exhaust, cooling, differential, and fuel storage is completely unnecessary. Building a new electric car from the frame up is a vastly more efficient means of having your own electric car. So that’s what he did.

[Gahaar] build his new chassis around a single box made of 3mm aluminum sheet. Attached to this box are two AC induction motors at the rear of the car, negating the need for a differential, with 45 lithium cells stuffed into the middle of the box. There’s no gearbox here, greatly reducing the complexity of the build, and with the batteries providing 145V and 100Ah, this simple car has more than enough power for a lot of fun.

The suspension and steering were taken from a wrecked car, in this case a Mazda MX5, or Miata for those of us in North America. The Miata suspension easily unbolts from the frame of the wrecked car, and with just a little bit of welding can easily be attached to the new electric chassis.

Even though [Gahaar]’s car is basically just a bit of aluminum, motors, suspension, and batteries, he’s getting some awesome performance out of it; he estimates a top speed of 100mph with about 60 miles per charge. It’s an awesome way to get around the farm, and with a custom fiberglass body, we can easily see this being one of the coolest electric vehicles ever made.

[Charles’s] Epic “Total-Recap” GoKart Post

charlesEVPost

If you’ve built an electric vehicle in the past few years, you probably owe [Charles] a couple of beers. Now you can feel more indebted to him after you read his 17,500-word, 10-part post covering everything you need to know about electric go-kart design. You’ll want to grab a sandwich to keep you company.

You probably recall the Chibikart from posts earlier this summer, which is one of an endless list of EV projects [Charles] has up his sleeve. He’s been teaching MIT students how to build EV karts for a while now, and this total-recap “2.00gokart” novel is [Charles’s] way of sharing the wealth. This is more than a simple how-to guide, though. Instead, it reads like a teacher’s edition of GoKarting 101, with a few brief and important histories, walk-throughs of how the class evolved, exhaustive links to vendors, graphs, videos, and plenty of reference and documentation.

If you have even the slightest interest in electric vehicles, do yourself a favor and give it a browse. There are a couple of videos after the break, and if you need some more motivation, check out the EV skateboard that uses a lot of the same parts.

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Porsche 911 made electric

[Kurt] wanted an electric car, and always wanted to drive a Porsche. Killing two birds with one stone, he decided to combine these wishes and convert a 2002 Porsche 911 into an electric vehicle.

After removing the engine, fuel tank, exhaust, radiator, and all the other things that make an internal combustion engine work, [Kurt] installed a high power motor, controller and 72 lithium phosphate batteries weighing in at over 500 pounds. He’s put over 300 miles on the car in the last few months while working out the kinks, but now he’s finally gotten the bugs out of the system allowing him to take it up to some relatively high speeds.

Already [Kurt] has taken his new ride to 100 mph and done a little bit of range testing that told him he should expect around 40 miles per charge in his new ride. It’s not exactly what he hoped, but more than enough for a few trips around town while riding in style.

After the break is a video [Kurt]’s first test drive of his electric Porsche.

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