Gravity-driven two-phase liquid cooling systems using flow boiling within micro-scale evaporators are becoming a game changing solution for electronics cooling. The optimization of the system's filling ratio can however become a challenging problem for a system operating over a wide range of cooling capacities and temperature ranges. The benefits of a liquid accumulator to overcome this difficulty are evaluated in the present paper. An experimental thermosyphon cooling system was built to cool multiple electronic components up to a power dissipation of 1800 W. A double-ended cylinder with a volume of 150 cm(3) is evaluated as the liquid accumulator for two different system volumes (associated to two different condensers). Results demonstrated that the liquid accumulator provided robust thermal performance as a function of filling ratio for the entire range of heat loads tested. In addition, the present liquid accumulator was more effective for a small volume system, 599 cm(3), than for a large volume system, 1169 cm(3), in which the relative size of the liquid accumulator increased from 12.8 % to 25% of the total system's volume.