diff --git a/esp32/include/ControllerConfiguration.h b/esp32/include/ControllerConfiguration.h
index 4d987da..1d0190a 100644
--- a/esp32/include/ControllerConfiguration.h
+++ b/esp32/include/ControllerConfiguration.h
@@ -144,7 +144,7 @@
 #ifdef HWREVISION07
 #define SOLAR_VOLT_FACTOR           (4.0306f) /**< 100k and 33k voltage dividor */
 #else
-#define SOLAR_VOLT_FACTOR           11f
+#define SOLAR_VOLT_FACTOR           11.0f
 #endif
 #define BATTSENSOR_INDEX_SOLAR      0
 #define BATTSENSOR_INDEX_BATTERY    1
@@ -160,7 +160,7 @@
 #define VOLT_MAX_BATT               4.2f
 #define VOLT_MIN_BATT               3.0f    /**< Minimum battery voltage for normal operation */
 #define LOWVOLT_SLEEP_FACTOR        3       /**< Factor for nightsleep delay, if the battery drops below minimum (@see VOLT_MIN_BATT) */
-#define LOWVOLT_SLEEP_MINIMUM       5400    /**< At low voltage sleep at least for 90 minutes */
+#define LOWVOLT_SLEEP_MINIMUM       7200    /**< At low voltage sleep at least for 120 minutes (two hours) */
 
 #define WATER_LEVEL_MINIMUM         500      /**< Minimum Analog value (1023 is the maximum)*/
 
diff --git a/esp32/src/main.cpp b/esp32/src/main.cpp
index 9f3165e..e5124bd 100644
--- a/esp32/src/main.cpp
+++ b/esp32/src/main.cpp
@@ -239,11 +239,14 @@ void espDeepSleep(bool afterPump = false)
     }
   }
 
+  #define SECOND2USECOND_FACTOR (1000U * 1000U)
+
   /* sleep always at least one second */
-  if (secondsToSleep < 0) {
-    secondsToSleep = 1;
+  if (secondsToSleep <= 0) {
+    secondsToSleep = (unsigned long) (UINT64_MAX / SECOND2USECOND_FACTOR);
   }
-  esp_sleep_enable_timer_wakeup((secondsToSleep * 1000U * 1000U));
+  esp_sleep_enable_timer_wakeup((secondsToSleep * SECOND2USECOND_FACTOR));
+  #undef SECOND2USECOND_FACTOR
   if (aliveWasRead())
   {
     delay(1000);