According to Jeff Liedel, OnStar's CIO, Chevy captured data, including the current charge state and trouble codes from the engine. (OnStar is owned by General Motors, as is Chevrolet, and provides the in-car safety systems that connect drivers with emergency and towing services, among other things.) Many of the onboard EV control modules are brand-new so, Liedel says, it was very important to capture specific data from the modules, including real-time diagnostics that showed how each module was performing. Then engineers were able to track and record this, analyze a data warehouse of diagnostic information, and tweak the design.
This kind of IT involvement is not new -- OnStar has captured test-fleet data from gas-powered cars before -- but the difference with the Volt was how quickly designers captured the data and made changes.
GM used IBM Rational software for logging changes, understanding the sensor data and communicating with the team about the changes. Designers used Compuware software to run computations on the collected data, to determine, for example, how often the car needed to be charged.
"We collected on the order of hundreds of individual pieces of data from each battery pack during the test fleet development," says Liedel. "We fed that data directly back to the individuals working in our battery lab. It's all about life-cycle testing and about correlating the results in the lab to real-world field trials as we developed the vehicle." The team also considered how charging affected battery performance for the cars that were operating in hot vs. cold climates, he explains.
For its part, BMW took a similar approach in designing the Mini E production car and BMW ActiveE concept car, which the German automaker will use for field trials this summer.
During the development phase, BMW worked with UC Davis to analyze data from test cars, says Rich Steinberg, BMW's manager of electric vehicles operations and strategy. BMW analyzed data on the battery, such as how turning on climate controls remotely while the car was connected to a charging station -- something you can do using Nissan's Carwings iPhone app -- impacted battery performance over the life of the test compared with not preheating or precooling.
To the BMW researchers' surprise, they found that most EV drivers tend to recharge at night, even if the EV is nowhere near empty. This habit will play well with the version of the Mini E that will be released in the United States. Leaving the car plugged in all night helps precondition the battery, which increases the car's driving range.
BMW was able to use this data, stored on a central server in Munich, to make design changes not just in the battery pack, but also in how the vehicles are made. For example, with the Mini E test, the company found that it could use lighter materials in construction that helped with overall range.