Bipolar nickel metal hydride batteries are of interest for intermediate power storage in hybrid electric vehicles. The special design allows to gain additional information on the state of charge (SOC). In order to keep a nickel metal hydride battery in a limited SOC range a battery management system is required. The influence of external conditions, like temperature, mode of operation and load profile to the quality of the operation of the quality of the battery management system are discussed. (c) 2005 Elsevier B.V. All rights reserved.