diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.cpp b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.cpp
index ac23bc44c8..83d33c8984 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.cpp
@@ -130,7 +130,7 @@ void AP_BattMonitor_SMBus_Generic::timer()
 }
 
 // read_block - returns number of characters read if successful, zero if unsuccessful
-uint8_t AP_BattMonitor_SMBus_Generic::read_block(uint8_t reg, uint8_t* data, bool append_zero) const
+uint8_t AP_BattMonitor_SMBus_Generic::read_block(uint8_t reg, uint8_t* data) const
 {
     // get length
     uint8_t bufflen;
@@ -164,11 +164,6 @@ uint8_t AP_BattMonitor_SMBus_Generic::read_block(uint8_t reg, uint8_t* data, boo
     // copy data (excluding PEC)
     memcpy(data, &buff[1], bufflen);
 
-    // optionally add zero to end
-    if (append_zero) {
-        data[bufflen] = '\0';
-    }
-
     // return success
     return bufflen;
 }
@@ -199,8 +194,8 @@ bool AP_BattMonitor_SMBus_Generic::check_pec_support()
     }
 
     // check manufacturer name
-    uint8_t buff[SMBUS_READ_BLOCK_MAXIMUM_TRANSFER + 1];
-    if (read_block(BATTMONITOR_SMBUS_MANUFACTURE_NAME, buff, true)) {
+    uint8_t buff[SMBUS_READ_BLOCK_MAXIMUM_TRANSFER + 1] {};
+    if (read_block(BATTMONITOR_SMBUS_MANUFACTURE_NAME, buff)) {
         // Hitachi maxell batteries do not support PEC
         if (strcmp((char*)buff, "Hitachi maxell") == 0) {
             _pec_supported = false;
diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.h b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.h
index 34a5b139f6..fd19a830b2 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.h
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_SMBus_Generic.h
@@ -26,7 +26,7 @@ private:
     bool check_pec_support();
 
     // read_block - returns number of characters read if successful, zero if unsuccessful
-    uint8_t read_block(uint8_t reg, uint8_t* data, bool append_zero) const;
+    uint8_t read_block(uint8_t reg, uint8_t* data) const;
 
     uint8_t _pec_confirmed; // count of the number of times PEC has been confirmed as working
     uint32_t _last_cell_update_us[BATTMONITOR_SMBUS_NUM_CELLS_MAX]; // system time of last successful read of cell voltage