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Electric car kit approved ?. Yes, in Spain and Europe.

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In recent years, electric cars have become more and more common, and the question,often is: which electric car to buy?.

With the new European directives, regulations to reduce CO2 emissions, the inflation of raw materials (copper, aluminum, lithium, etc.) and the problems in the supply chain, it becomes increasingly obvious that the way forward is to retrofit, that is to convert a car into electric.

The most obvious advantage is the price, and that is that converting a small city vehicle with a car conversion kit to electric can have the same or less price than buying an electric car without a license.

And without looking at the price, the fact of giving our planet earth less work and making real use of the circular economy is the most important reason.

By buying an electric car, we will have promoted the manufacture of a car from scratch, with the resulting waste of energy and resources, while converting it with a conversion kit, we will be recycling and reusing a car that would otherwise go to scrap.

Well, we are ready to offer our first “approved car kit in Spain” (and in Europe), in this case for the fabulous classic Mini. And more approved kits will follow the Mini: VW Beetle, Seat 600, Seat Ibiza, Renault Kangoo,…

The kit will be tested, approved and ready for distribution in 2023.

And what does this approved kit consist of?

The kit has a three-phase induction electric motor of 18Kw of sustained power and 35Kw of maximum power. Air-cooled and weighing about 50Kg, it will be capable of developing a maximum torque of 150Nm.

The brain of this kit will be a 108V controller with a sustained output current of about 250A, air-cooled, which makes it easier to maintain, and with a power capacity of up to 55Kw and an energy efficiency of 98%.

The batteries for the prototype will be a 10Kw lithium battery pack with its corresponding charger (the final battery pack is yet to be determined), more than enough for urban use for the Mini.

It also has a 12V dc-dc converter so that the auxiliary battery continues to power the car lights.

Also, the kit will have all the other extras such as signal wiring, high-voltage cable (so that the conversion is very simple without the need to add anything else) and a console with all the information on the Mini (led aesthetics or Mini aesthetics)

The entire drive assembly is installed on the Mini’s sub-frame, so mechanical installation is a simple step from replacing the old sub-frame with the new one from the kit. Something that the car workshops will appreciate because of how easy and fast this operation is.

How will the kit approval process be?

Well, as simple as there is nothing to do. The kit will be distributed with the approved conformity reports (including the batteries approved with the R100V2), which will suffice with the workshop certificate that assembles it to go to the Technical inspection service (MOT in the UK) and update the Mini’s technical sheet.

The Mini will be a similar vehicle, weighing exactly the same (about 650 kg), with its four seats and running on electricity, it will be possible to obtain the ZERO label without any difficulty. Of course, a silent, more fluid drive, with regenerative braking and ready to continue being driven for many more years.

Telemetry confirmed good news.

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We went to the speed track, in Cartagena, where we could use the track for some time. We thank you very much for their help.

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We decided to drive a non-stopping run at a constant current, to see how other aspects of the prototype (our electric Twingo), as range, temperatures, rpms..etc. . were affected.

 

Due to the amount of corners the track had, we couldn’t get a stable current consumption, but at least we could monitor it, and that was the result for 20 min drive.

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We can see an average of 120 Amp out of the battery pack most of the time. And also, around 210 Amp out of the controller.

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All this time we have consume around 3,3 Kw, which is a stoning 46% of the total capacity.

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But, ¿how this test affected to the rest of the components?. Well, we could see the controller a bit too hot, so that led us to think about an additional cool system for the controller. We saw a peak of 72ºC, which is the limit of a healthy temperature, so we are working in some system to dissipate faster the temperature of the heat sink controller.

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The motor also was a bit warm, but we could see a very healthy average between 40ºC and 50ºC, so no drama about it, for now.

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We can also see that we tried to get the motor at the stable revolution rate of 2500 rpm, which is the manufacturer  recommended rpm rate to get the maximum torque. Seeing that we did drive a maximum rpm efficiency it is also good news. So, Telemetry came ok at Cartagena´s speed track.

 

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So, a little video with a summary of the whole test can be enjoyed here. If you need a professional video recording work for your project, please contact:  Tecnoforma, victor.aldaya@tecforma.com

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Testing, testing, .. out road.

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60_testingThe conversion of a petrol or diesel vehicle is the most sustainable and economical way of driving a perfect electric car. The main idea behind this, is to re-use all the vehicle´s components that have no impact in the internal combustion engine, and to substitute it with a full electric motor. Engine, radiator, petrol tank, exhaust tubes, alternator, etc will be removed, reducing the car´s weight. By having a chassis with all the necessary parts for driving, as interior, brakes, tyres, shock absorbers, etc, all effort is reduced to install and design an electric system with a motor and batteries.

61_testingIt is very important to choose a good design for the electric system, electric motor, battery pack and motor controller should have the same specifications in power and speed to the ones the car when it was originally designed. Too much power could damage the traction components or may not respond as well to breaking, and too little could cause the gears no to acquire the adequate speed.

Elektrun is a project that was born two years ago to probe the concept of transforming a city car to electric, ideal for short trips within the city.  We have chosen a Renault Twingo to build a prototype,  it is a vehicle with little weight and a reduced size, and after two years of design, test and experiments we have made it work.

62_testingThe main issue for this kind of transformation is the range the batteries will achieve. Now days there are cars that can drive 700kms in one single charge, in order to achieve that, it needs at least between 70Kw and 80Kw. Our prototype comes with a 7,4Kw.

 

 

63_testingThis prototype has an 15KW AC induction motor with a maximum torque of 80Nm, a battery pack of 72V and 100Ah, it has an 80V and 350Amp controller. This can speed the car to 90km/h in 5th gear.

The first tests shown the total weight didn’t affect at all in corners, the shock absorbers responded well as expected, and by removing the engine noise the driving was much more comfortable.

64_testingAn additional vacuum pump was installed to help the braking system. The braking was also performing very well as, it responded to hard braking and kept the car stopped in steep ramps.

 

65_testingA small display was installed in the interior to monitor, at any time, battery usage, current, motor temperature, state of charge, etc.

 

66_testingLights and interior accessories as electric windows, radio, air flow, window cleaner, etc were kept in the car.

This car takes 8 hours to fully charge the battery pack, although there are chargers that could reduce this time from 6 to 4 hours.

 

 

You can see a video about the first tests here:

Coupling, make it right the third time.

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This is one of the most, if not the most important and tricky mechanical manipulations you have to do when converting a vehicle into electric. Connecting the electric motor to the existing transmission is a big debate, as you can just connect both axis together with some sort a coupler or do it using a clutch.

 

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Usually, both axis have different diameter, splines or are in C-fase (as they say in America), so you will need two different couplers, one for each shaft (motor and gear-box).

 

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Now, those two couplers can be connected directly or with the original clutch (there is a big debate around this subject). In our case, we will follow the clutch design. The main reason is efficiency, as having the ability of changing gears, will give you more efficiency in all cases of the driving, such short, medium and long gears. Although this approach is a bit more complicated in implementing, as the flywheel needs to be adapted to the motor shaft, the driving of the car will be as similar as with the combustion engine.

The first part of this transformation is to have the adapter plate mounted in the motor so the flywheel attached keeps in the same position in relation to the gearbox.

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Then, we need to attach the flywheel to the motor with an adapter. You can use a steel coupler from Lovejoy or Rotex, machined exactly for the electric motor shaft. It is also very important to measure all the components including the clutch that will go inside the gearbox, so they all fit perfectly.

Once the flywheel machined and attached to the motor, it is time to screw the clutch to the flywheel. From that point on, the operation it is just a standard clutch installation.

 

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Now, in the 1st attempt to install the clutch, it all went smooth a part from a little periodic noise from inside the gearbox. So, we had to dismantle the clutch again to see what happened. Our surprise was that the flywheel was touching very lightly inside the gearbox. That was the 1st problem easily solved by reducing the flywheel or by carving a bit the specific gearbox area where the flywheel was touching.

 

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Another and second problem was the flywheel, even that was correctly inserted into the splined motor shaft; it wasn’t properly screwed, so that centrifuge force could cause the flywheel to move forwards touching the gearbox shaft. So apart from soldering a coupler in the centre of the flywheel, we asked for a whole too to be able to screw and stop the flywheel.
Now this modification caused to move the block flywheel-clutch forwards 6 mm, so we had to cut the gearbox shaft 7 mm.

 

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Also we discovered that the flywheel wasn’t properly turning flat respect the axis, so we sent it to a machinist to rectify that tiny difference and also to reduce the diameter of the flywheel, with that we solve 2 issues. Removing mass of it, so it would had less inertia and also avoid touching the gearbox inside.

 

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The final result was this 3rd attempt, where the flywheel was turning flat against the clutch disk, was fitted to the motor shaft, the diameter was much smaller, so it wouldn’t touch inside the gearbox and had less mass, so less inertia and better performance. It needed to be balanced (to have the same mass radially so it wouldn’t vibrate at high rpm) , but as the flywheel was already balanced when manufactured, we trust it would still be balanced after the rectification. The gearbox shaft was also cut 7 mm to receive the motor block. And once all modified it all fitted as a glove.

 

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The final result fitted quite well. Tested at high rpm and ahd no vibrations at all.

 

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Batteries, The big deal.

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The batteries world is in constant change nowadays with the electric vehicles take off , the new and improved power storage, super capacitors, and the new kid on the block, graphene.

Lead batteries and AGM or gel are a thing of the past. We are now having the Li-ion present going to the new Li-air future.

The necessity of longer trips, fast charging times a better performance are a must in electric vehicles, and more and more, those demands are the big deal in EV.

Fresh air, still to come.

Till now, the obvious technology in the batteries department has been lithium-ion. But since some time ago, a new technology based in air is the real interest for manufacturers and EV developers. The new Li-air promises up to 10 times the energy density of their cousins li-ion. IBM´s project 500 has the aim of driving 500 miles in one single charge  in a family car using those new batteries. Although this has been achieved already by the Metron Institute (Slovenia) with LiFePo4 technology.

Li-air cells

The way it works is, a Li-air cell uses cheap carbon as a cathode (instead of cobalt), a molecule of a oxygen pivots through the cathode and gives the battery its name. But it has remained theoretical because of its big challenges. Among them: the other electrode in such batteries—the anode—is pure lithium metal, which provides a lot of energy but also ignites when exposed to water, carbon dioxide, or other contaminants.

Such is the challenge, that IBM and JCESR (Joint Center for Energy Storage Research) have decided to step back from the LI-air project, and IBM has turned his favour to a Lithium Sodium technology.

Li-Na cells

But with all these changes, a new development continues, and metal chemistries are also under development, in particular Aluminium-Air. An Israeli company (Phinergy), has claimed to solved corrosion, and recharging issues with a silver based catalyst. A prototype EV claimed to have 1600km range with Al-air batteries. However those cells cannot be electrically re-charged having to re-load them mechanically and topped up with water.

It smells sulphur.

Lithium Sulphur cells are another energy dense technology that could solve the needs for the EV in a near future. This new chemistry tends to solve issues like life cycle and stability. Based around a carbon based electrode, those cells are said they could go ahead Li-air technology.

Li-S cells

Many studies and research from Imperial College (London)  to German company BASF are putting their efforts into Li-S. They said this could be the 4th generation of batteries, expecting ranges of 400Kms in the next decade. Scientists at Lawrence Berkeley Labs (California) have introduced graphene oxide into Li-S cells that are said to deliver 1,500 charge cycles without deterioration.

Other researchers from ETH Zurich are working with Sodium-ion cells, stating that are much cheaper than Li-ion. But they have two major problems; they are three times heavier than lithium and tend to lose capacity when not in use.

Lithium Ion are here to stay.

Despite all the development in the power storage field, one thing is clear, most of EV at the moment go for Li-ion, and the fact that manufacturer are offering cheaper prices and even Tesla is building a new Lithium batteries plant, makes you think that in the long term this technology is here to stay.

Li-ion cells

Li-Ion developers, Bosch, GS Yuasa and Mitsubishi, claim that the could reduce the prices to half in the Li-ion filed, and double the capacity, that would make EV much more approachable to normal consumers.

There are also many new promising developments with carbon, but the gap between the lab and the factories is too big to stop producing Li-ion for EVs.

graphene cells

The magazine “Electric & Hybrid Vehicle Technology International” writes in their July 2014 issue about the carbon:

“The real deal?. A new type of dual-carbon battery technology that could potentially be a game changer for EVs has been launched by a Japanese R&D company. Called Ryden, the new battery is said to offer energy density that’s comparable to Li-ion products, but over a much longer functional lifetime with far improved safety and cradle-tocradle sustainability, says Power Japan Plus, which will begin production of the cells later this year at its manufacturing facility in Okinawa, Japan. The Ryden battery makes use of a completely unique chemistry, with both the anode and the cathode made of carbon. “Power Japan Plus is a materials engineer for a new class of carbon material that balances economics, performance and sustainability in a world of constrained resources,” says CEO Dou Kani. “The Ryden dual-carbon battery is the energy storage breakthrough needed to bring green technology such as electric vehicles to mass market.” Kani says that the Ryden battery balances a breadth of consumer demands previously unattainable by a single battery chemistry. In terms of performance, the new battery is not only energy dense and operates at above four volts, but also offers a charge time that’s 20 times faster than that of current Li-ion designs.

dual carbon cellsThe Ryden technology has been created so that it can slot directly into existing manufacturing processes, requiring no change to existing manufacturing lines. Furthermore, the battery enables consolidation of the supply chain, with carbon being the only active material used. As a result, manufacture of the Ryden battery is under no threat of supply disruption or price spikes from rare earth materials, rare metals or heavy metals. According to Power Japan Plus, its technology is the first high-performance battery that meets consumer cycle-life demands, being rated for more than 3,000 charge/discharge cycles. The breakthrough also eliminates the unstable active material used in other high-performance batteries, thus greatly reducing fire and explosion hazard. Furthermore, the new battery experiences minimal thermal change during operation, eliminating the threat of a thermal runaway. Finally, it can be 100% charged and discharged with no damage. Adding to the sense that the Ryden battery could be a key moment for EVs is that it is 100% recyclable, vastly improving the cradle-to-cradle sustainability of battery technology. As an add-on to this, Power Japan Plus is testing the battery with its organic carbon complex material, working toward the goal of producing the battery with all-organic carbon in the future. Made of naturally grown organic cotton, the carbon complex exhibits properties not seen in other carbon materials. By controlling the size of the carbon crystals during production, Power Japan Plus can engineer the carbon complex for a variety of applications.”