Lithium-ion Battery Energy Storage Systems (BESS) are to be the next household electrical appliance in a smart grid environment. This is beside the growth of electrical vehicles with lithium-ion batteries. However, these batteries are yet to prove their performances in the household sector. This paper presents the performances of a small household scale battery energy storage system with a lithium-ion battery pack and a single-phase ac-dc inverter. Results of a list of tests conducted in a lab environment are presented explaining the test procedures and results. Test results show that the considered BESS is suitable for daily cycling applications but has low efficiencies at the rated power operations. Converter losses contribute to the low efficiency of the considered BESS. The BESS is more efficient in lower power (lower than rated) operations. However, the effects of the current harmonics need to be considered when it is operated with other appliances.