Case Studies

One way to understand what we do and how Cobasys can provide the right solutions and products to solve your needs is to learn what we have done for others.

Denver Regional Transportation District selects Cobasys for its Hybrid Fleet Application

The Denver Regional Transportation District (RTD) began testing two passenger buses in early 2004 outfitted with Cobasys advanced Nickel Metal Hydride (NiMH) battery systems. The buses, originally fitted with lead acid batteries, have performed remarkably well over a wide range of temperature conditions in the Denver area. Successful testing has yielded improved performance and a marked increase in operation compared to lead acid batteries.

Denver RTD introduced a fleet of 36 mall shuttle buses in 2000. The buses’ hybrid electric propulsion system is powered by compressed natural gas (CNG) and electric motors. Each bus can carry up to 116 passengers driven by electric battery-powered motors that are recharged by only a small 4-cylinder CNG engine.

Denver RTD approached Cobasys indicating that they were not satisfied with the performance of the lead-acid battery system in their hybrid bus fleet. Short battery life and the need for reliable battery monitoring were the greatest concerns that needed to be addressed.

The solution provided by Cobasys was the NiMHax 288-120, a system consisting of two NiMHax 288-60 sub-packs connected in parallel, which utilizes the Cobasys flexible high power Series 1000 NiMH battery module to provide a nominal voltage of 288 volts and 120 kilowatts of power. A complete battery system - the NiMHax 288-120 includes: a battery management system, thermal management system, and CAN communications - all of the components required for reliable operation. In addition, Cobasys supplied on-site technical support for the installation of the battery systems and continual monitoring of the batteries.


NiMHax 288-60 Standard Pack, the foundation
for the 288-120 system used for Denver RTD's application.

The optimal solution provided by Cobasys married our batteries and our battery management system with the buses’ electric propulsion system. The NiMHax 288-120 system offered Denver RTD better performance, greater reliability and a superior battery management system. Since the battery footprint on the bus did not change, the NiMHax battery system provided more power than lead acid batteries in the same amount of space.

The main advantage for Denver RTD is increased battery life and more uptime for their hybrid buses. Cobasys will be converting an additional ten Denver RTD hybrid buses from lead acid batteries to their Nickel Metal Hydride (NiMH) battery system solution.

Tecnobus Gulliver Case Study

The Tecnobus Gulliver is an electric transit bus, powered by our NiMH battery systems, deployed in Rome, Italy. It is able to travel 113 miles on a single charge, versus only 38 miles when it was powered by a conventional lead-acid battery.  Its maintenance-free NiMH battery is also 22% lighter and has more than twice the life span of the conventional lead-acid battery, which required daily maintenance.

Transit buses are a particularly exciting application for our NiMH battery systems because they not only reduce pollution, but by carrying many passengers, they reduce urban gridlock. The Tecnobus Gulliver is an electric transit bus, powered by our NiMH battery systems, deployed in Rome, Italy. It is able to travel 113 miles on a single charge, versus only 38 miles when it was powered by a conventional lead-acid battery. Its maintenance-free NiMH battery is also 22% lighter and has more than twice the life span of the conventional lead-acid battery, which required daily maintenance.

Napa Valley Unified School District Case Study

The NiMH battery systems have a proven track record, delivering record-breaking range in a number of vehicles. Our battery systems hold the world record at 373 miles on a single charge set during the Tour de Sol competition in 1997. Our battery systems are beginning to be used in heavy-duty transit vehicles. An example is the all-electric 72-passenger school bus that carries students to and from school at the Napa Valley Unified School District in California. The 30,000+ pound prototype school bus is powered by a robust, energy-dense NiMH battery system with >100 kilowatt hours (kWh) of energy storage that provides >100 mile range. Our NiMH battery systems provide about 25% greater range, 50% reduction in weight, and improved safety, life, and reliability over the lead-acid version. At mid-day, the Blue Bird electric bus is capable of rapid-charging via a 60 kilowatt (kW) fast-charger provided by AeroVironment, who collaborated with our team on the advanced battery management system. Our NiMH battery systems that powered the school bus was developed through partial funding from the Defense Advanced Research Project Agency (DARPA), the California Energy Commission (CEC), and the Sacramento Municipal Utility District (SMUD).

HEV Battery System Case Study

Cobasys has been involved in numerous development programs for fully integrated hybrid electric vehicle (HEV) battery systems.

Cobasys has been involved in numerous development programs for fully integrated hybrid electric vehicle (HEV) battery systems.

One such program has resulted in the development of a system for a major automotive customer to fulfill its specific HEV application requirement. Working closely with the customer, our engineers have developed the battery system to fit in the demanding underbody environment of the vehicle, packaging around the vehicle frame and cross members.

This required a custom engineered approach and close working relationship with vehicle engineers and designers. The system was fully sealed and designed for underbody environmental and chemical environments. The battery system also included a liquid-cooled thermal management system (TMS), and a CAN-based (Controller Area Network) battery management system, which communicated with the vehicle controller to ensure optimum battery performance. The system was produced using production-intent processes and tooling and is undergoing automotive validation testing. With over 40 kW of power capability, the system met customer expectations and is currently powering its vehicles as the development program continues.

GM EV1 Case Study

As a testimony to our heritage, our NiMH battery systems powered the first mass-produced EV electric vehicle – the GM EV1 – in 1996. Our NiMH battery systems have powered approximately 1000 GM EV1s for a combined total of 1,000,000 plus miles. Our NiMH battery systems have enabled the EV1 to have a real world range of 250 km. For another electric vehicle project, the Chevy S10 Pick-up Truck achieved a range of 110 to 130 km with full payload.

Solectria Case Study

In 1996, the standing world record of over 373 miles on a single charge was set by Sunrise, a Solectria EV Race car powered by our advanced NiMH battery pack.

The journey to excellence began in 1994, when we publicly unveiled our highly regarded NiMH battery in a Solectria Force EV Race car in the APS Electrics race in Phoenix, Arizona. This car, which was driven by James Worden, CEO of Solectria, won first place in that event.

Later that year, the same vehicle competed in the Tour de Sol – an electric vehicle road rally driven on real surface streets in New England – to win first place and to set a world record (in its vehicle-type for range) of 214 miles on a single charge. However, another Solectria electric vehicle, the Force, powered by our NiMH batteries, broke that record one year later. In this event, the Force set a new record of 238 miles on a single charge.

Since then, there have been other public demonstrations of the performance level of the NiMH batteries in Solectria vehicles, including another Tour de Sol – a drive from Boston to New York City on a single charge. This event was aired on Good Morning America TV program.



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