Determining power stealing capability of a climate control system controller

Disclosed are exemplary embodiments of systems and methods for determining a power stealing capability of a climate control system controller. In an exemplary embodiment, a controller for use in a climate control system generally includes a capacitor chargeable by current flowing through an off-mode load of the climate control system. A voltage detect circuit detects a voltage across the capacitor. The controller includes a timer for determining a charge time of the capacitor from a first specific voltage to a second specific voltage based on input from the voltage detect circuit. The controller determines a resistance of the off-mode load based on the charge time and, based on the determined resistance, determines a level of current for power stealing through the off-mode load.