diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.cpp b/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.cpp
index 58ca05cab6..60dda33e48 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.cpp
@@ -146,16 +146,17 @@ void AP_BattMonitor_UAVCAN::read()
     _has_temperature = (AP_HAL::millis() - _state.temperature_time) <= AP_BATT_MONITOR_TIMEOUT;
 }
 
-/// capacity_remaining_pct - returns the % battery capacity remaining (0 ~ 100)
-uint8_t AP_BattMonitor_UAVCAN::capacity_remaining_pct() const
+/// capacity_remaining_pct - returns true if the percentage is valid and writes to percentage argument
+bool AP_BattMonitor_UAVCAN::capacity_remaining_pct(uint8_t &percentage) const
 {
     if ((uint32_t(_params._options.get()) & uint32_t(AP_BattMonitor_Params::Options::Ignore_UAVCAN_SoC)) ||
         _soc > 100) {
         // a UAVCAN battery monitor may not be able to supply a state of charge. If it can't then
         // the user can set the option to use current integration in the backend instead.
-        return AP_BattMonitor_Backend::capacity_remaining_pct();
+        return AP_BattMonitor_Backend::capacity_remaining_pct(percentage);
     }
-    return _soc;
+    percentage = _soc;
+    return true;
 }
 
 #endif
diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.h b/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.h
index 9582893c74..a3ad6b9732 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.h
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_UAVCAN.h
@@ -24,8 +24,8 @@ public:
     /// Read the battery voltage and current.  Should be called at 10hz
     void read() override;
 
-    /// capacity_remaining_pct - returns the % battery capacity remaining (0 ~ 100)
-    uint8_t capacity_remaining_pct() const override;
+    /// capacity_remaining_pct - returns true if the percentage is valid and writes to percentage argument
+    bool capacity_remaining_pct(uint8_t &percentage) const override;
 
     bool has_temperature() const override { return _has_temperature; }