Long battery charge times and low battery charge-discharge cycle life are the two major limitations holding back the commercialization of electric vehicles. In order to resolve these problems, a robust battery system was developed by Microvast Inc. The batteries can be charged in less than 10 minutes and rapidly charged and discharged up to 20,000 times, while still maintaining more than 80% of the original capacity. 6 City Buses utilizing the Microvast battery systems have been tested in commercial operation in Chong Qing, China for more than one year. The batteries are still in good condition. The improved Li₄Ti₅O₁₂ negative electrode material gives the Microvast battery system its excellent properties. In April, 2012, modules were removed from the buses and analyzed for capacity retention, increased impedance, and constant current capacity. In order to evaluate capacity retention, 5 cells were removed from the module and evaluated The nominal 1 C capacity of the 5 cells was tested at 1 C and compared with original delivery capacity data. Averaging these 5 cells, we observed about a 0.7% capacity loss, with a maximum capacity loss of 2.7%. In order to test for impedance gain, initial impedance data was compared with that of the 5 removed cells. The impedance rose from 0.662 mOhm initially to 0.676 mOhm. An increase of about 2% was observed. When testing for constant current capacity loss, the ratio of initial capacity of 5C constant current charging was compared with that of the removed cells. Nominal constant current capacity decreased from 90.2% to 88.6%. Based on the results of the tested cells and modules, the data shows very good results after 2,000 ultrafast charging cycles.