If you can’t move it to blip it on, then that may be the problem. Just holding it down doesn’t allow it to restart into what is effectively permanently on mode so long as the clip holds the button down. But you must be able to move your hold-down to do the restart. Otherwise, it’s basically my instructions above [to the best of my current knowledge.]
This needs field-testing, if for no other reason to see if power consumption is within the capacity of current batteries and panels. In the winter, the slight heating effect might even be desirable. People should report back their findings when the weather allows.