diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.cpp b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.cpp
index 6d4589d1fa..591c8fe521 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.cpp
@@ -11,9 +11,11 @@
 #include "AP_BattMonitor_SMBus_Solo.h"
 
 #define BATTMONITOR_SMBUS_SOLO_CELL_VOLTAGE         0x28    // cell voltage register
+#define BATTMONITOR_SMBUS_SOLO_CELL_VOLTAGE_EXT     0x29    // cell voltage register up to 6s
 #define BATTMONITOR_SMBUS_SOLO_CURRENT              0x2a    // current register
 #define BATTMONITOR_SMBUS_SOLO_BUTTON_DEBOUNCE      6       // button held down for 5 intervals will cause a power off event
 #define BATTMONITOR_SMBUS_SOLO_NUM_CELLS            4       // solo's battery pack is 4S
+#define BATTMONITOR_SMBUS_SOLO_NUM_CELLS_EXT        6       // extended BMS supports up to 6s
 
 /*
  * Other potentially useful registers, listed here for future use
@@ -39,12 +41,12 @@ AP_BattMonitor_SMBus_Solo::AP_BattMonitor_SMBus_Solo(AP_BattMonitor &mon,
 
 void AP_BattMonitor_SMBus_Solo::timer()
 {
-    uint8_t buff[8];
+    uint8_t buff[12];
     uint32_t tnow = AP_HAL::micros();
 
 
     // read cell voltages
-    if (read_block(BATTMONITOR_SMBUS_SOLO_CELL_VOLTAGE, buff, 8)) {
+    if (!_use_extended && read_block(BATTMONITOR_SMBUS_SOLO_CELL_VOLTAGE, buff, 8)) {
         float pack_voltage_mv = 0.0f;
         for (uint8_t i = 0; i < BATTMONITOR_SMBUS_SOLO_NUM_CELLS; i++) {
             uint16_t cell = buff[(i * 2) + 1] << 8 | buff[i * 2];
@@ -62,6 +64,25 @@ void AP_BattMonitor_SMBus_Solo::timer()
         _state.healthy = true;
     }
 
+
+    // read extended cell voltages
+    if (read_block(BATTMONITOR_SMBUS_SOLO_CELL_VOLTAGE_EXT, buff, 12)) {
+        float pack_voltage_mv = 0.0f;
+        for (uint8_t i = 0; i < BATTMONITOR_SMBUS_SOLO_NUM_CELLS_EXT; i++) {
+            uint16_t cell = buff[(i * 2) + 1] << 8 | buff[i * 2];
+            _state.cell_voltages.cells[i] = cell;
+            pack_voltage_mv += (float)cell;
+        }
+        _has_cell_voltages = true;
+
+        // accumulate the pack voltage out of the total of the cells
+        _state.voltage = pack_voltage_mv * 1e-3f;
+        _state.last_time_micros = tnow;
+        _state.healthy = true;
+        // stop reqesting 4-cell packets.
+        _use_extended = true;
+    }
+
     // timeout after 5 seconds
     if ((tnow - _state.last_time_micros) > AP_BATTMONITOR_SMBUS_TIMEOUT_MICROS) {
         _state.healthy = false;
diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.h b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.h
index f14b0e16c0..b9083f5747 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.h
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Solo.h
@@ -18,6 +18,7 @@ private:
     void timer(void) override;
 
     uint8_t _button_press_count;
+    bool _use_extended;
 };
 
 #endif  // AP_BATTERY_SMBUS_SOLO_ENABLED