I have a simpel project with 2 SSD relays. It works fram a charge adepter 230V or computer, but not from cigarett adepter 12V 5V 2,1 A
You will need to provide technical details of the project and of the two different power supplies.
but not from cigarett adepter 12V 5V 2,1 A
That would suggest that there is a problem with the 12V adapter. Is the output from the adapter really 5V, open circuit? Is the output from the adapter still 5V when the adapter is connected to the circuit?