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A123 Systems introduces Li-ion 6T battery designed specifically for military applications; engine start and silent watch

The military is interested in replacing lead-acid batteries with higher performing Li-ion systems. From a 2011 TARDEC presentation. (Skalny). Click to enlarge.

A123 Systems has introduced the Military 6T Battery, a robust Li-ion battery system engineered specifically to meet the demanding requirements of military vehicles. The 6T is a standard form factor (10.5 in. x 10 in. x 8.5 in.), and is used in a wide range of applications.

A123’s 6T solution, which has been in the works for about 1.5 years, was developed with input from the US Army Tank Automotive Research, Development and Engineering Center (TARDEC), said Les Alexander, general manager for the Government Solutions Group at A123. A123’s 6T is designed as a direct replacement for 6T lead acid batteries currently deployed in military vehicles delivering a longer-lasting, lighter-weight system for engine start and enabling longer-duration silent watch functionality.

In a 2011 SAE paper, a team from TARDEC noted that replacing lead-acid batteries military vehicle batteries with a Li-ion system would offer a number of benefits. These include doubling the reserve time of the stock battery and delivering a significantly greater number of charging and discharging cycles while also providing weight savings. Additionally, they noted, there is no acid inside a lithium ion battery to cause corrosion, which eliminates potential damage to a vehicle from chemical spills and poisonous gases. However, they also noted:

...the characteristics, including the charge and discharge control of lithium ion battery chemistries, are different from those of flooded and sealed lead acid batteries. The traditional continuous battery charging approach may potentially result in overcharge and thus raise safety concerns for lithium ion battery replacement. In addition, lithium ion batteries experience reduced battery service life when exposed to very low and deep discharge levels...Although lithium ion battery replacement may have value for vehicle applications that have strict weight and volume requirements, and a need for increased power, their higher cost, low temperature performance, and sophisticated controls may create challenges when they are used in place of traditional vehicle SLI lead acid batteries.

—Ding et al.

A123 Systems believes it has worked through those issues. Based on A123’s proprietary Nanophosphate lithium iron phosphate technology, the Military 6T Battery leverages the systems engineering and manufacturing design utilized to produce A123’s 12V Engine Start Battery (earlier post), which is currently offered to commercial automakers. The Military 6T Battery is offered in both a 12V and 24V model to accommodate specific vehicle requirements. Standard features and benefits of each of A123’s 6T battery models include:

  • Longer Cycle and Calendar Life. A123’s Military 6T Battery systems are designed to perform significantly more depth of discharge cycles compared to other battery technologies. A123’s lithium iron phosphate military batteries also deliver superior calendar life, lasting significantly longer than the most advanced lead acid batteries. This reduces battery replacement costs, enables vehicles to operate for longer periods of time and reduces life-cycle cost.

  • Greater Charge Acceptance Rate. A123’s lithium ion technology is capable of rapid charging, and it also delivers more power when the engine is off to facilitate longer-duration silent watch capabilities.

  • Reduced Weight. A123’s Military 6T Battery is about 50% lighter than lead acid battery systems, offering significant weight savings for transport to the battlefield. This improves fuel economy and packing efficiency of the transport vehicle which allows for fewer trips into hostile areas.

  • Intelligent Battery Management System. In addition to lithium iron phosphate cells, A123’s Military 6T Batteries are equipped with battery management electronics that help balance and safeguard the cells, in addition to providing built-in system level safety features for under/over voltage cutoff, overcharge and over-temperature protection. The battery management system also communicates diagnostics, state-of-charge information and current and voltage measurements during silent watch, maximizing the performance of the Military 6T Battery when operating communications, surveillance and other equipment while the vehicle’s engine is not running.

Alexander said that A123 has done ballistics testing as part of its safety testing.

There are three major phases of launching a military product, Alexander said: proof of concept and testing; vehicle qualification; and manufacturing. A123 is in the first phase, and prepared to enter the second.

Manufacturing sets us above the rest. We are already doing commercial batteries, we already have the factories in place. Our path to production is pretty smooth.

There is no doubt that we are not going to be the cost parity of lead-acid, but we are at least three times the life and only 3-4 times the cost, and costs come down. We are also half the weight. Weight is very important. Third, look at the functionality of what they want the battery to do. To improve the silent watch mission, turn off the vehicle, run the equipment for the appropriate period of time. You can do silent watch, and recharge the battery rapidly. Our value proposition is better life, improved functionality and longer rate.

At the end of the day, the military will get a highly reliable, highly manufactured product at good cost. They will not get a customized product with a cost premium—that’s where they’ve gotten into some trouble. They’ve developed specs around their needs, and paid a premium for the products. If we take a manufactured approach, looking at how we ruggedize our products for their needs, it’s a much easier proposition than looking at a clean sheet of paper and looking for a new chemistry.

—Les Alexander

There are nearly 800,000 6T batteries currently deployed in US military vehicles, Alexander said, and in 2010 alone, the military purchased about 300,000 6T batteries—virtually all of which were lead-acid.

The A123 6T has demonstrated the ability to start a High-Mobility Multipurpose Wheeled Vehicle (HMMWV), and the company has begun delivering 6T systems to a number of defense contractors so they can evaluate its performance as a first step toward potential high-volume production.

I think the 6T will help the commercial side. What the military provides is a platform to challenge the upper limits of the chemistry. You get a wider range of operating temperatures, a wider range of duty cycles to advance the commercial products.

—Les Alexander

A123 is showcasing its Military 6T Battery and other government and military solutions during the Association of the United States Army (AUSA) Winter Symposium. The 6T-12 and 6T-24 versions of A123’s advanced lithium iron phosphate military battery solution are available now, and pricing is available upon request.


  • Ding, Y., Zanardelli, S., Skalny, D., and Toomey, L. (2011) Technical Challenges for Vehicle 14V/28V Lithium Ion Battery Replacement. (SAE Technical Paper 2011-01-1375) doi: 10.4271/2011-01-1375

  • Technical Challenges for Vehicle 14V/28V Lithium Ion Battery Replacement (presentation) 



I hope A123 makes the grade. If this is a 'drop-in', are the Li-ion charge/control electronics included.

Frankly, the 50% lighter factor seems more important to cars or electric wheelchairs etc. than 70 ton tanks.


This is aimed at Humvees. Weight is a factor because every pound of battery requires fuel to push and takes away a pound of payload.


Hmmm. Since the cost of the supply lines is a major factor in conflicts these days, how soon before A123 or Via Motors proposes a PHEV Hummer? If a pallet-load of solar panels delivered to a camp could cut the fuel requirements by as little as half, the payback would be enormous.


Yes, that is the idea. Supply line is a huge task, so if the troops can supply themselves they can go farther and longer. Turning trash into fuel, sun into energy, any way you can keep them mobile without a huge logistical overhead helps.


One field soldier used 1 gal/day in WWII. With all our technical progress, 1 field soldier now requires 22 gal/day and is a major supply nightmare. This 22X increase in 60 years of continued progress does not make much sense.

PHEVs: Lighter Tanks, Trucks, Humvees, Jeeps etc using smaller more efficient diesel or micro turbines + ultra high efficiency solar panels could probably cut the fuel required per soldier to 11 gal/day or less.

Our soldiers, like many of us, are convinced that 'Bigger and Heavier is Better' and will have difficulties to adapt to new lighter materials and more efficient war machines like flying pilot-less micro-mini-robots etc.


M1 tanks in Gulf I had thirsty turbines, we need to think outside the box. With drones and lasers we may not need tanks and artillery. Just spot them and vaporize them, mission accomplished.

Dave R

They need to make a consumer version of this designed for the enthusiast/racing crowd.

A lot of people will pay hundreds for a small, light, durable, long-lasting battery for their regular automobile.


I can see the advantage of a Hummer with no noise nor heat signature. If you want to go stealth, this would be one way to do that. Imagine a base with Hummer car ports made with solar panel roofs. 400 square feet would provide enough energy to go 40 miles per day, that is a decent patrol with no petrol.

Bob Wallace

I doubt that patrol vehicles travel far from field bases.

How about PHEV Hummers with swappable ~30 mile battery packs?

A couple sets of batteries could be charging off solar panels all day. Swapping could be done via a low tech system in which a "stick" of batteries could be slid into/out of a battery tunnel with a simple wench. Think about batteries strung out along where a transmission tunnel would be.


The good thing with solar and advanced batteries in the middle east is there is plenty of sun. The rest of the power could be used for the base. I doubt you could air condition your tent, but it might reduce the amount of liquid fuel required for generators.


If you're interested in national energy security issues, you might want to check out:

Securing America's Future Energy (SAFE) is a non-partisan organization working to reduce our dependence on oil.


Forget carports, make the shelters out of PV panels for their outer skins. Kill two birds with one stone.

To kill another bird, back the panels with vacuum insulation filled with fumed silica. This keeps the heat of sun-drenched panels out of the interior and improves performance in winter also.


Sounds good to me, that might even give the U.S. solar panel industry a needed customer to keep them in business and competing worldwide.


I can see it now - 2112 - An Army Admiral comments to a Navy Sargent, "Why are these battery cases so big? The battery" inside is about the size of a BB and all of the computer controls are about the size of a pin head.

The Sargent replies, "You know how it was way back in 2012. Nobody would question how things had always been done. You know there still thousands of Navy Generals and Hundreds of Army Admirals that are still convinced you can pipe Hydrogen from one side of the country to another?"



Each Km of hardware to be moved on a battle field requires energy, mainly liquid fuel. Much lighter materials could be used to reduce army vehicles weight by 50% without affecting their usefulness. Hybridization and electrification could further reduce the use of very expensive liquid fuels. As mentioned above, large tents covered with flexible solar panels could supply most of the (sustainable) energy at lower cost.


I see here opportunity for redox batteries in combination with wind and solar panels. Charging redox electrolyte during day and filling in vehicles could be option. Electrolyte could be seen as additional protection since it is not explosive and could prevent penetration.

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