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M-Beam Challenge's converted 2002 Volkswagen Golf will use system of modular battery exchange to keep the car moving over the estimated 60 hour drive from San Diego to South Carolina coast.

The M-BEAM Challenge

Fastest Coast-To-Coast Crossing of the US in an Electric Vehicle

By Steve Shrinkle

In August of 2013, we officially kicked off the M-BEAM project with the purchase of a 2002 Volkswagen Golf. Our project was simple, but our aspirations were substantial: we intended to transform it into an electric vehicle (EV) that was capable of crossing the United States in record time, around 60 hours.

The idea behind this started a few years ago when we saw the need for a solution to range anxiety and battery degradation. Most modern EVs have very limited range and take a long time to recharge. Fast charge has been the most recent industry trend, but even this has its limitations. Even on short journeys over a few hundred miles, an EV is required to stop for half an hour at a time, minimum, just to charge and keep going. This severely limits the ability for full scale adoption of electric automobiles. From my father’s experience with batteries and battery management systems, he was able to come up with a system that could handle the exchange of hand-held battery modules, at electric vehicle power levels. We called this M-BEAM.

M-BEAM stands for Modular Battery Exchange and Active Management and is the reason we are able to attempt the record drive. The idea behind M-BEAM is quite straightforward. If your car has depleted batteries, take them out and replace them with new ones. This is with small, manageable battery modules that you could manually remove and replace at any exchange station. Current, commercial electric vehicles only contain one large battery pack, which is usually fixed in the car’s chassis. Others have had the full pack become removable, however, this is proving to not be a reasonable solution. We think that the future of EVs is in small, removable modules. Battery cells will shrink considerably in the future making this refueling method clearly superior to fast charge which can only achieve a fixed number of miles for a given amount of charge power over time.

The reason you don’t see this now is because maintaining and balancing a mix of old, depleted batteries at those power levels is extremely difficult. Start mixing in different chemical makeups of batteries and it’s next to impossible. This is where the “AM” part of M-BEAM comes in. Through our active battery management system, we can take batteries of varying charge level, chemistry, age, or condition and keep all cells discharging and charging uniformly. We can even replace only a portion of the depleted modules and continue driving.

When we thought about how we could actually implement the M-BEAM system, we were a little overwhelmed. There was no way we were going to tackle the automotive industry into submission to use modular batteries. After much debate, we decided to do a demonstration at the grassroots level to see what kind of traction we might get with all the interested parties. We thought, “What better way to prove the capabilities than with a drive across the country?” This would demonstrate the modular exchange process as if someone were to complete a trip across the country themselves.

However, no cross country trip is an easy thing. This would require logistics. We recruited a team of EV enthusiasts, mechanical engineers, electrical engineers, software engineers, and an ME professor and his students at UCSD to help us with this task. These team members would perform two duties: assist in designing and building the car and helping to drive across the country. Since at some point on the trip, we are going to need some sleep, our team consists of six, rotating drivers: two in the car (one driver & one navigator) and the remaining four in a following passenger van, sleeping, eating, and getting on each other’s nerves. When we reach a depleted state on the batteries, freshly charged batteries will be put into the car, and driving will resume. Allowing for an estimated exchange time of around 3-4 minutes to fully swap out the batteries, we believe that, following the speed limit of course, we can depart from San Diego and reach the coast of South Carolina just shy of 60 hours.

Some people have wondered why we decided to do this and what our goals are in driving across the country. We are simply are a group of engineers from various backgrounds who are passionate about electric vehicles and innovative technologies. One of us has been in the disk drive industry for many years, but also has many years of battery technology experience. Others are in the aerospace/satellite industry and have been working as structural analysts for a few years. And another is a computer programmer PhD student. This diverse group is held together by a common factor: their enthusiasm towards electric vehicles. In addition to satisfying our fascination with EVs, we also think that the trip is a great way to get involved in the EV community and to start the discussion about modular batteries.

In order to complete trip across the country, we needed a durable chassis with a low coefficient of drag (decreased air resistance) that was easily convertible to an electric car. We decided on the four-door Volkswagen Golf due to its ease of conversion, low drag coefficient, lightweight structure, and ample space for battery storage. A few days after we bought the car, we brought in our mechanic to do his magic. The Volkswagen Golf turned out to be a very easy car to work with when converting into an EV. With some greasy hands and a sturdy hoist, we pulled the gas engine out of the car, leaving an empty hole. After some more work, we had the gas tank, alternator, and other unnecessary parts stripped from the car.

The next step was to get the Warp 9 motor into the engine compartment. With a couple custom machined brackets, we had the motor hooked right up to the transmission. A few days later, we had the liquid cooled Soliton 1 controller installed, a DC-DC converter bolted down, and a brake vacuum pump connected. When you convert a gas car into an electric vehicle, it really becomes quite evident how simple and elegant an EV is compared to a combustion engine car.

We are now at the most crucial step of the build: the battery modules. It took time to get these designed with the active management circuitry, but they are turning out to exceed all of our expectations. All of the circuitry is up and running and we are in the midst of bench testing them now, as we are still in the prototype stages right now of the battery build. There is plenty more work to be done in preparation for the challenge and we will certainly keep you up to date!

If you are interested in finding out more about M-BEAM, the team, our project, or just want something new to look at, feel free to visit our website: modularexchange.com. If you want to stay connected with updates about the project, you can follow us on Twitter at MBEAMXC or on Facebook at M-BEAM. And don’t be shy if you have questions, drop us a line at mbeamchallenge@gmail.com.

Project Photos

2002 VW Golf prior to M-BEAM conversion

Warp9 electric motor during installation

M-BEAM hot swappable lithium-ion battery

Times Article Viewed: 3193
Published: 29-Dec-2013

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