diff --git a/docs/ESP32_clock_adjust.xlsx b/docs/ESP32_clock_adjust.xlsx
index 95f0f0c..fcd260c 100644
Binary files a/docs/ESP32_clock_adjust.xlsx and b/docs/ESP32_clock_adjust.xlsx differ
diff --git a/lib/RTC/PCF85063_Driver.cpp b/lib/RTC/PCF85063_Driver.cpp
index 36422c3..9d2b9d7 100644
--- a/lib/RTC/PCF85063_Driver.cpp
+++ b/lib/RTC/PCF85063_Driver.cpp
@@ -1,5 +1,6 @@
 #include "PCF85063_Driver.h"
 #include <ctime>
+#include <utils.h>
 
 namespace drivers
 {
@@ -18,7 +19,7 @@ namespace drivers
             success &= m_i2c.write(m_address, RTC_CTRL_2_ADDR, {def_conf2});
         }
         // set clock correction pulses
-        const uint8_t correction = 0b10000011; // fast mode +3 correction pulses, because clock is beyond
+        const uint8_t correction = 0xE7; // fast mode -25 correction pulses, because clock is beyond
         success &= m_i2c.write(m_address, RTC_OFFSET_ADDR, {correction});
         if (!success)
             LOG_ERROR("RTC Init Failure");
@@ -160,6 +161,22 @@ namespace drivers
         return false;
     }
 
+    const bool PCF85063::setOffset(const uint8_t ofst)
+    {
+        LOG_INFO("RTC set offset [", printHex(ofst).c_str(), "]");
+        return m_i2c.write(m_address, RTC_OFFSET_ADDR, {ofst});
+    }
+    
+    const uint8_t PCF85063::getOffset()
+    {
+        std::vector<uint8_t> buf;
+        if (m_i2c.read(m_address, RTC_OFFSET_ADDR, 1, buf)) {
+            LOG_INFO("RTC get offset [", printHex(buf.front()).c_str(), "]");
+            return buf.front(); 
+        }
+        return {};
+    }
+
     const std::string PCF85063::getTimeStr()
     {
         datetime_t dt;
diff --git a/lib/RTC/PCF85063_Driver.h b/lib/RTC/PCF85063_Driver.h
index c166e05..d6dd88e 100644
--- a/lib/RTC/PCF85063_Driver.h
+++ b/lib/RTC/PCF85063_Driver.h
@@ -83,7 +83,7 @@ namespace drivers
     } datetime_t;
 
   public:
-    PCF85063(I2C &i2c, const uint8_t address, const uint8_t ctrl1 = RTC_CTRL_1_DEFAULT, const uint8_t ctrl2 = RTC_CTRL_2_DEFAULT);
+    PCF85063(I2C &i2c, const uint8_t address = PCF85063_ADDRESS, const uint8_t ctrl1 = RTC_CTRL_1_DEFAULT, const uint8_t ctrl2 = RTC_CTRL_2_DEFAULT);
 
     const bool reset(void);
 
@@ -100,6 +100,9 @@ namespace drivers
     const bool readAlarm(datetime_t &time);
     const bool getAlarmFlag(uint8_t &flags);
 
+    const bool setOffset(const uint8_t ofst);
+    const uint8_t getOffset();
+
     const std::string getTimeStr();
 
     static const std::string datetime2str(const datetime_t &datetime);
diff --git a/src/main.cpp b/src/main.cpp
index edb4d2e..7797318 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -34,7 +34,7 @@ void loop()
   // Declared here to keep devices local to the main loop otherwise the kernel crashes //
   auto i2c = drivers::I2C();
   auto bus = drivers::MODBUS(9600, SERIAL_8N1);
-  auto rtc = drivers::PCF85063(i2c, PCF85063_ADDRESS);
+  auto rtc = drivers::PCF85063(i2c);
   auto eth = drivers::Ethernet(conf.m_ethHostname);
   auto tmp = drivers::R4DCB08(bus, conf.m_modbusTemperatureAddr);
   auto seneca = drivers::S50140(bus, conf.m_modbusSenecaAddr);