It seems that your Bluetti setup, consisting of 1 Bluetti AC300 and 4 Bluetti B300 units, is unable to power your Samsung RF 261 MP refrigerator or your GE 17 cf refrigerator. Even with fully charged batteries and no other devices connected, the refrigerators refuse to start up. This could be a compatibility issue between the Bluetti setup and the refrigerators. I would recommend reaching out to the Bluetti customer support team for assistance. They should be able to provide you with specific guidance and troubleshooting steps to resolve the problem.