Power　routing　(PR)　provides　a　good　choice　to　improve　the　modular　converter　reliability　by　equalizing　the　lifetime　among　multi-cells.　The　existing　PR　strategies　just　equalize　the　lifetime　of　power　semiconductor　devices　by　routing　lighter　loads　for　aged　cells.　However,　the　neglect　of　capacitor　may　mislead　the　multi-cell　lifetime　convergence.　Besides,　the　light　load　allocation　of　the　aging　cell　does　not　always　mean　the　lifetime　extension　considering　topologies　and　operation　principles.　Hence,　this　article　proposed　a　capacitor　lifetime-based　PR　for　input-series-output-parallel　connected　dual　active　bridge　converter.　The　proposed　strategy　can　achieve　the　same　accuracy　as　existing　PR　strategies,　greatly　reducing　computation　time　and　the　complexity　of　the　hardware　circuit.　Moreover,　the　nonmonotonic　relationship　between　the　damage　growth　rate　and　load　of　each　cell　is　revealed　and　a　damage　growth　rate　constraint　is　developed　to　ensure　the　PR　feasibility.　Simulation　is　performed　to　verify　the　validity　of　the　proposed　strategy　and　constraints.　Finally,　a　scaled　down　prototype　has　been　developed　to　verify　the　PR　feasibility　and　obtain　the　nonmonotonic　relationship,　verifying　the　necessity　of　proposed　constraints.　In　addition,　the　effect　of　PR　on　the　thermal　stress　and　cumulative　damage　of　capacitors　is　verified　by　a　temperature　test.