John Petersen's  Instablog

eOver the last couple weeks there's been a lot of message board chatter about ePower Engine Systems, a transportation technology company that has selected the PbC® battery from Axion Power International (AXPW.OB) for its series hybrid electric drivetrain for over-the-road freight haulers who drive heavy Class 8 tractors. Since I introduced ePower to Axion and have tracked their progress for a couple years, I called ePower's CEO Andy Claypole to ask his permission to share what I've learned about ePower's hybrid electric drivetrain.

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After a series of phone calls and e-mails, Andy graciously sent me a technical presentation on ePower's series hybrid drive and gave me permission to share the presentation with readers and discuss ePower and its technology in greater detail. Click here to download a copy of ePower's presentation.

ePower Engine Systems LLC is a closely-held advanced transportation technology developer that's using inexpensive off-the-shelf components to bring series electric drive, the mainstay of the nation's rail transportation system, to highway transportation. Their goal is to narrow the fuel efficiency gap between 480 ton miles per gallon for railroads and 110 ton miles per gallon for heavy trucks.

In a truck with series electric drive, there is no mechanical connection between the engine and the wheels. Instead, the engine powers a generator and electricity from the generator powers an electric drive motor. This configuration maximizes fuel efficiency by running the engine at its optimal RPM and eliminates the need for complex heavy truck transmissions while delivering the instantaneous peak torque of an electric motor.

In furtherance of their goal to maximize fuel efficiency, ePower takes series electric drive a step further by sizing the generator for steady vehicle state operations at highway speed and using an array of 52 PbC batteries to provide additional power for acceleration and hill climbing, and increased energy savings from regenerative braking. The ePower drivetrain is a true series hybrid electric drive and a first for the trucking industry. The design is suboptimal for mountainous routes with substantial elevation changes, but it's extremely efficient in flatter terrain.

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While a typical Class 8 tractor operating in the US with an 80,000 pound gross vehicle weight achieves fuel economy in the 5.2 mpg range, the same truck with an ePower system will deliver fuel economy of 10 to 14 mpg, values that crush the DOE's 2018 SuperTruck target of 6.8 mpg for conventional heavy trucks. It works out to an annual fuel savings of roughly 11,500 gallons per vehicle.

During the startup phase, ePower has focused on the retrofit market because around 37% of the 2.7 million trucks in the US-fleet are more than five but less than twelve years old. These trucks have outlived their original drivetrain warranties and are often less efficient than newer trucks, but they have substantial remaining useful life in their chassis, bodies and other components.

The cost of converting a tractor with a conventional diesel drivetrain to a series hybrid electric drivetrain is approximately $70,000 (batteries included) and ePower believes its retrofits will pay for themselves through fuel savings alone in 18 to 24 months.

Currently, ePower is doing all required retrofit work in its own facility. Once its system is fully developed and proven, ePower intends to provide the necessary conversion components in kit form for sale to certified installers including fleet operators and other service entities. It also hopes to license its technologies and systems upstream into the OEM market.

ePower's original design used absorbed glass mat, or AGM, batteries to provide acceleration and hill climbing boost. Unfortunately, the AGM batteries were poorly suited to long-string use and ePower was not satisfied with the frequency of battery failures. The AGM batteries also tended to degrade rapidly, which impaired acceleration and hill climbing boost while diminishing the efficiency of regenerative braking systems. ePower believes the long-string behavior and high dynamic charge acceptance of Axion's PbC battery will overcome both of these challenges.

The PbC batteries were delivered to ePower in mid-November and installed in swappable battery boxes that will give ePower the ability to switch back and forth between the old AGM batteries and the new PbC batteries in a couple of hours. During the first week in December, ePower plans to conduct a series of benchmarking tests to compare the on-road performance of the two battery systems in the same vehicle. It will then devote the rest of December to a road show for potential customers. In early January, the first PbC powered truck will be delivered to ePower's customer and a second AGM powered truck will be brought back into the shop for a PbC upgrade.

I believe the ePower system is intriguing for several reasons. Firstly, it's a frontal assault on fuel costs, the biggest expense burden in the trucking industry. Secondly, ePower's initial marketing efforts are directed at medium to large fleet operators who are more inclined to assume the risk of testing an idea in real world conditions instead of devoting years to laboratory work. Thirdly, the ePower system is an extremely efficient use of batteries. Finally, it doesn't take much market penetration in a million-unit fleet to represent a substantial revenue base for ePower and Axion.

If results from ePower's prototype demonstrations are favorable, there is a significant likelihood that several large freight operators will purchase multiple retrofits for similar testing programs to determine where series hybrid electric drivetrain would fit into their operations. ePower's series hybrid electric drive system is not a silver bullet solution for all truckers and all routes, but the economics can be very compelling for firms with established routes and schedules where a series hybrid electric drivetrain can do the required work at a lower cost.

Disclosure: Author is a former director of Axion Power International (AXPW.OB) and holds a substantial long position in its common stock.

Disclosure: I am long AXPW.OB.

One of the more intriguing presentations at ELBC 13 was an evaluation of the Ultrabattery by the University of Sheffield. In their study, the researchers compared four device configurations including:

• A conventional AGM battery;
• An AGM battery in parallel with a 200 Farad supercapacitor;
• An AGM battery in parallel with a 2400 Farad supercapacitor;
• A Furukawa Ultrabattery.

By the time they adjusted for voltage differences between the battery and the supercapacitors, the 200 Farad supercapacitor pack resulted in a 33 Farad system and the 2400 Farad supercapacitor pack resulted in a 416 Farad system.

Since the researchers used a BoostCap from Maxwell Technologies (MXWL) for their 2400 Farad parallel string, the following impedence chart compares the Ultrabattery with the technical equivalent of the Maxwell-Continental system.

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As I understand the impedence chart, the Ultrabattery performed better than the AGM battery or the AGM battery in parallel with a small supercapacitor module, but worse than the AGM battery in parallel with a large supercapacitor module.

I was surprised because I always assumed that the Ultrabattery would have more capacitance than the Continental-Maxwell system and that doesn't seem to be the case.

While Axion Power International (AXPW.OB) doesn't typically talk about the capacitance of the PbC, the unsuccessful DOE grant application it filed jointly with GM in February 2011 did note, "The large capacitance of the PbC battery (13,000F) means that it can support typical vehicle loads for up to 600s above 12V without the need for charging."

I'm sure there's more in the University of Sheffield presentation than I've been able to glean for myself, but it should give some of our more knowledgeable friends something to chew on.

Disclosure: I am long AXPW.OB.

My materials from the European Lead Battery Conference in Paris arrived late last week and while there weren't many presentation graphs that were simple or clean enough for an investing blog, Norbert Maleschitz, the technical director of Germany's Banner Battery and the winner of the 2012 International Lead Award for lifetime contributions to the lead acid battery industry used this graph to show the dynamic charge acceptance differences between normal lead-pastes and lead pastes with carbon additives.

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It's unclear whether the batteries were flooded or AGM, but Banner is a primary battery supplier to both BMW and Audi so my best bet is that he was comparing AGM rather than flooded batteries.

The thing I like most about this graph is that it clearly shows while carbon additives do improve DCA, the gains are unimpressive when you remember that automakers want DCA in the 100+ Amp range for today's heavy micro-hybrids and even higher for their next generation micro-hybrids. It is worth noting that Exide Technologies (XIDE) has hitched its wagon to the carbon additives star.

In his presentation, Enders Dickenson of Axion Power International (AXPW.OB) reminded delegates that the 2010 test results from Axion and BMW showed stable DCA of 100 Amps through 50,000 cycles. He also reported that Axion's current dual battery system demonstration is using a charge current of 150 Amps for a dual battery system where 91% of the charging load is absorbed by the PbC and 9% is absorbed by the flooded starter battery.

If the PbC performance lines were superimposed on the Maleschitz graph, the old values would be near the bottom of my first paragraph and the new values would be near the top of my first paragraph.

Disclosure: I am long AXPW.OB.