Skateboard concept turns tubular as Trexa reveals the Enertube

Trexa Enertube chassis prototype – Click above for high-res image gallery

Trexa has finally raised the blinds over at their workshop and revealed that its skateboard platform concept has turned tubular. Totally! The light of day glinting off the production chassis reveals a structure with all the unnecessary bits removed and the remainders incorporated into a shiny torque tube connected to a set of wheels via a pushrod suspension set-up.

The changes leave its modular adaptability intact and perhaps quite improved. The 7 kWh lithium phosphate battery pack of this initial 96-inch long example can be doubled by changing the diameter of the Enertube from from nine inches to twelve. As well, the length can be stretched and the system is said to be capable of supporting everything from a golf cart to a class 8 truck with a 100 kWh battery.

Trexa has teamed up with a specialty vehicles manufacturer for commercialization and customers will receive the first evaluation platforms in May. Additionally, the company has partnered with Carnegie Mellon Robotics to develop "advanced functionality platforms for government and agricultural applications." It's also generated interest from a major auto racing league with an eye towards an all-electric series.

The smaller outfits haven't been forgotten either and CEO Seth Seaberg credits the "re-emergence of electric drive" to grassroots efforts and hopes to offer products for independent, kit and custom car builders in the future. Check out the gallery below then hit the jump for all the details in the official press release.

[Source: Trexa]
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Los Angeles, April 11, 2011--Trexa LLC, the electric drive vehicle platform manufacturer,
announced today the filing of a U.S. patent application for its Enertube™ tubular energy
storage technology in connection with the unveiling of the TREXA® production
prototype. The first TREXA vehicle platforms will be shipped to customers for evaluation
in May.

While the TREXA concept vehicle platform introduced early last year featured an iconic "skateboard" form, the production platform is pure function. Driving this design is the Enertube, which is an energy storage system that doubles as the main load-bearing structure for a variety of vehicles. This proven concept of using a so-called "torque tube" or "backbone" chassis dates to the 1960ʼs. Differentiating the TREXA platform are interchangeable parts on all four suspension corners, which keeps parts count low, makes platform integration fast, and makes maintenance easy for end-users. All the major mechanical subsystems, including the transaxle, are manufactured by TREXA in the USA with support from Tier 1 automotive suppliers.

Vehicle applications mount to the TREXA vehicle platform by way of several hard points located on the front and rear suspension subframes. The subframes are attached to the Enertube. A pushrod suspension and 2WD or dual-motor 4WD options enables broad adjustability for both on and off-road applications. After a vehicle application is mated to
these subframes, the Enertube is able to be removed for maintenance or future upgrade of the modular battery. The current generation Enertube utilizes thermally stable lithium iron phosphate cells and a proprietary third-generation BMS (battery management system), which have been extensively tested and proven since the TREXA engineering team developed EDrive, the first commercially demonstrated li-ion PHEV, in 2006.

Central to the TREXA patent application is scalability of the battery system. The nine inch diameter Enertube utilized on the 96" wheelbase prototype contains 7 kWh of energy storage capacity, suitable as a platform for a local use plug-in vehicle or small series PHEV. However, small increases in tube diameter dramatically increase energy storage capacity. For example, an increase in diameter from nine inches to twelve yields a twofold increase in energy capacity. TREXA plans to offer Enertube-based platforms in a range of diameters and lengths, representing energy storage capacities to over 100 kWh. As a result, TREXA platforms could be the basis for electric drive vehicles ranging from golf carts to Class 8 trucks.

TREXA has formed an alliance with a large publicly-traded specialty vehicle manufacturer to commercialize the platform and Enertube technology. TREXA is also exploring electric racing in connection with a major auto racing league. In addition, the company is working with the Carnegie Mellon Robotics Institute to develop advanced functionality platforms for government and agricultural applications. The company plans to make specific announcements about its developer and supplier relationships in the coming months.

"TREXA is both a learning and a teaching company," said CEO Seth Seaberg. "We have spent a great deal of time in the past few years understanding what our developers need so we can educate them about, and provide them with, the appropriate and scalable battery technology. The Enertube is the culmination of that considerable effort."

Although initially it will work with established vehicle manufacturers and automotive R&D divisions, TREXA does have future plans to offer systems to independent, kit and custom car builders. "The DIY market has incredible potential, and there is no question that the re-emergence of electric drive is a result of grassroots efforts," said Seaberg. "So we are exploring how and when we might offer platforms, development guidelines, and support to the general public."

TREXA is funded in part by Crunch Energy LLC, a firm dedicated to developing innovative new technologies that help the world use less energy. TREXA expects to close its next round of funding this summer.

For more information, visit the companyʼs web site,, email

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