Method for managing battery charging so as to prolong battery life

The invention discloses an exemplar embodiment of a controller used in an environment control system and a method. In the exemplar embodiment, the controller used in the environment control system comprises a charger which is used for providing charging current for a battery in the controller. The controller further comprises a variable resistor which is used for selectively limiting the charging current. A control device is configured to monitor the charging current and battery voltage. Based on the monitoring, the control device changes resistance so as to enable the monitored voltage to be kept within a range limited by upper charging voltage (a) lower than the full capacity of the battery and final discharging voltage (b) higher than cut-off voltage of the battery. The monitored voltage has a fully minimized change ratio within the range.