A method of charging a metal-air fuel cell. The method includes a step of orienting an anode chamber horizontally. The method further method includes a step of providing metal particles suspended in an electrolyte to flow through the anode chamber in a downstream direction oriented horizontally. The method further method includes a step of allowing a bed of the metal particles to form on the anode current collector. The plurality of particle collectors perturb the flow of electrolyte through the anode chamber and encourage settling of the particles one of on and between the particle collectors. The method further method includes a step of maintaining uniform formation of the bed.