A heating, ventilation, and air conditioning (HVAC) controller may include a housing and a printed circuit board (PCB) situated within the housing. The PCB may include a battery seat region and electrical terminals for electrically connecting a battery to the PCB when the battery is positioned at the battery seat region. The housing may include an opening that may be configured to receive the battery. The battery seat region may be at least partially offset relative to the opening in the housing, but accessible via the opening. The housing may be configured to allow the battery to be inserted into the opening and then moved laterally to the battery seat region, where the battery may be at least partially covered and/or protected by the housing when at the battery seat region. In some cases, the battery may be inserted within the housing without adjusting any part of the housing.