Disclosed are exemplary embodiments of controllers and methods for use in climate control systems. In an exemplary embodiment, a controller for use in a climate control system includes a charger for providing a charge current to a battery of the controller. The controller also includes a variable resistance for selectively limiting the charge current. A control is configured to monitor the charge current and a voltage of the battery. Based on the monitoring, the control varies the resistance to keep the monitored voltage in a range defined by (a) a top charge voltage less than full capacity of the battery and (b) a discharge end voltage greater than a cut-off voltage of the battery. The monitored voltage has a substantially minimized rate of change within the range.