This paper focuses on the bidding strategy and online control methodology of battery storage systems (BSS) to participate in the frequency containment reserve (FCR) market. The new technical requirements for the FCR markets in the Nordic power system does not allow controlling the BSS in other ways than on the basis of frequency. Therefore, control mechanisms such as recovering the state of charge (SOC) whenever the power system frequency is in its acceptable (dead-band) range cannot be used. In this regard, this paper proposes and compares different control mechanisms to recover the SOC that are in line with the new regulation and maximizes the BSS profit using the lifetime model of the BSS. In order to compare different control mechanisms, this paper investigates the behaviour of a large BSS unit installed in the Helsinki area by simulating the proposed strategies over measured frequency and market data from 2014 till 2019.