To　meet　the　increased　heat　dissipation　demands　of　5G　base　stations,　a　flat　plate　heat　pipe　array　(FPHPA)　of　500　×　200　×　3　mm3　comprising　of　19　independent　channels　is　developed.　To　investigate　the　thermal　performance　of　the　FPHPA　under　different　filling　ratios　(FR)　and　heat　powers　(30–300　W),　a　multi-channel　independent　filling　system　is　designed　to　conduct　two　experimental　cases:　uniform　or　asymmetric　filling　of　all　channels.　Results　indicate　that　30　%–70　%　FR　exhibits　better　thermal　performance　and　can　replace　the　aluminum　plate　over　a　broader　heat　power　range.　Furthermore,　separate　tests　are　conducted　to　evaluate　the　heat　transfer　and　start-up　performance　of　the　FPHPA.　The　optimal　filling　ratio　interval　of　single　channel　at　different　heat　fluxes　is　derived　through　asymmetric　filling.　Subsequently,　a　mixture　model　is　proposed　and　compared　with　the　uniform　filling　ratio　case,　resulting　in　optimized　heat　transfer　performance.　The　optimized　FPHPA　provides　better　heat　transfer　performance,　effectively　reducing　the　area　averaged　wall　temperature　and　ensuring　the　normal　operation　of　the　5G　base　station.　©　2023　Elsevier　Ltd