diff --git a/src/M5StamPLC.cpp b/src/M5StamPLC.cpp
index c76e713..ab78d01 100644
--- a/src/M5StamPLC.cpp
+++ b/src/M5StamPLC.cpp
@@ -233,6 +233,7 @@ void M5_STAMPLC::rx8130_init()
     if (!RX8130.begin()) {
         ESP_LOGE(TAG, "rx8130 init failed!");
     } else {
+        RX8130.initBat();
         RX8130.disableIrq();
         RX8130.clearIrqFlags();
     }
diff --git a/src/utils/rx8130/rx8130.cpp b/src/utils/rx8130/rx8130.cpp
index 3985803..11a169e 100644
--- a/src/utils/rx8130/rx8130.cpp
+++ b/src/utils/rx8130/rx8130.cpp
@@ -81,6 +81,14 @@ bool RX8130_Class::begin()
     return result;
 }
 
+void RX8130_Class::initBat()
+{
+    uint8_t data = readRegister8(RX8130_REG_CTRL1);
+    // Enable backup battery charging
+    data |= 0b00110000;
+    writeRegister8(RX8130_REG_CTRL1, data);
+}
+
 void RX8130_Class::setTime(struct tm *time)
 {
     uint8_t rbuf = 0;
diff --git a/src/utils/rx8130/rx8130.h b/src/utils/rx8130/rx8130.h
index 5a4ec02..f23bd8d 100644
--- a/src/utils/rx8130/rx8130.h
+++ b/src/utils/rx8130/rx8130.h
@@ -18,6 +18,7 @@ class RX8130_Class : public m5::I2C_Device {
 
     bool begin();
 
+    void initBat();
     void setTime(struct tm *time);
     void getTime(struct tm *time);
     void clearIrqFlags();