An article of clothing includes a garment body, a heater coupled to the garment body, a battery holder separate from the garment body and including a power terminal, and a rechargeable battery pack including a housing and a plurality of battery cells received in the housing and configured to provide power to the heater. The battery holder is detachably couplable to the garment body. The rechargeable battery pack is electrically connectable to the power terminal. The housing is detachably couplable to the battery holder. At least a portion of the housing is external to the battery holder when the rechargeable battery pack is coupled to the battery holder.