This MIB typically has power supply info:
CISCO-ENTITY-FRU-CONTROL-MIB
OID 1.3.6.1.4.1.9.9.117
This is what comes back on one of my 5548
CISCO-ENTITY-FRU-CONTROL-MIB cefcPowerRedundancyMode.470 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcPowerRedundancyMode.471 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcPowerUnits.470 CentiAmps @ 12V
CISCO-ENTITY-FRU-CONTROL-MIB cefcPowerUnits.471 CentiAmps @ 12V
CISCO-ENTITY-FRU-CONTROL-MIB cefcTotalAvailableCurrent.470 6500
CISCO-ENTITY-FRU-CONTROL-MIB cefcTotalAvailableCurrent.471 6500
CISCO-ENTITY-FRU-CONTROL-MIB cefcTotalDrawnCurrent.470 1062
CISCO-ENTITY-FRU-CONTROL-MIB cefcTotalDrawnCurrent.471 850
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerAdminStatus.22 1
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerAdminStatus.24 1
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerAdminStatus.470 1
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerAdminStatus.471 1
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerOperStatus.22 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerOperStatus.24 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerOperStatus.470 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUPowerOperStatus.471 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUCurrent.22 -4100
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUCurrent.24 -200
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUCurrent.470 6500
CISCO-ENTITY-FRU-CONTROL-MIB cefcFRUCurrent.471 6500
CISCO-ENTITY-FRU-CONTROL-MIB cefcMaxDefaultInLinePower.0 0
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleAdminStatus.22 1
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleAdminStatus.24 1
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleOperStatus.22 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleOperStatus.24 2
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleResetReason.22 0
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleResetReason.24 0
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleStatusLastChangeTime.22 1076
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleStatusLastChangeTime.24 6602
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleLastClearConfigTime.22 833478139
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleLastClearConfigTime.24 833478139
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleResetReasonDescription.22 Disruptive upgrade
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleResetReasonDescription.24 Disruptive upgrade
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleUpTime.22 0
CISCO-ENTITY-FRU-CONTROL-MIB cefcModuleUpTime.24 0
CISCO-ENTITY-FRU-CONTROL-MIB cefcMIBEnableStatusNotification.0 True