Battery backup devices and systems for garage door openers

A battery backup system for a garage door opener, the system comprising:

• a removable and rechargeable battery pack;
• and
• a battery backup device including
• a housing;
• an accessory port configured to receive an accessory;
• a power input module configured to receive alternating current (“AC”) power;
• a power output module configured to output AC power to an AC power outlet;
• and
• a controller configured to
• provide power to the accessory port,
• receive power from the removable and rechargeable battery pack, and
• control a switch between a first mode of operation and a second mode of operation, the first mode of operation including providing the received AC power to the power output module, the second mode of operation including providing power from the removable and rechargeable battery pack to the power output module,
• wherein, when the power input module is receiving AC power, the switch is controlled to the first mode of operation, and
• wherein, when the power input module is not receiving AC power, the switch is controlled to the second mode of operation.