Is there anything that means to put a 2nd power source at the 12 V distributor of the WW which only supplies electricity from time to time? Specifically, I play with the idea of putting solar power to the connection that normally brings 12 V from the car to serve the corresponding consumers. My concerns are, then something is possibly double charged, or comes back current when sometimes both power suppliers hang on one access and it becomes too much? Or is there then even a “short” I am Laie and ask before I do something wrong.