A method used for determining the capacity of a battery. The method includes determining, via a controller, if the battery has a first capacity sufficient to support a conditioning cycle. In response to determining that the battery has the first capacity sufficient to support the conditioning cycle, the conditioning cycle is activated. The method includes partially discharging the battery at a constant rate while measuring a plurality of battery parameters. A second capacity of the battery is estimated based on the battery parameters measured at the constant discharge rate. The method increases estimation accuracy of the battery's capacity.