Can I hook battery tender through cigarette socket in 2003 BMW 325i?

Question

I want to plug in my battery tender to the cigarette lighter socket rather than using alligator clips to the battery. The socket is hot (i.e., the cigarette lighter works) even when the ignition of off and key is removed.

Problem is that the green light on the battery tender never becomes a solid green. It is always flashing and red light is always on (solid). So, it does not seem to be taking a full charge.

Answer 1

The only problem that I have seen by doing it this way is that you can cause the cigarette lighter to overheat...

You can use it if you wire it through a bosch relay so the relay will take the load off of the cigarette lighter….