I thought this info might help some of you since PulseTech« info does not cover it.
Solargizer Solar Charger Installation Manual
Page 4 of the SOL Manual.PDF covers the LED but I was having some odd things happen so I called PulseTech« 1-800-580-7554 and spoke to one of the technicians and got some useful additional information.
I let him know that I had noticed about a week after installing an IS-24-L / 735X150 that the LED was not on. But if I put my hand near the wires coming out of the solar panel, the LED would flash. If I removed it, the LED would stop flashing.
The technician let me know that under full sun the LED should be on fully, that under partial sun the LED should blink, and that with no sun the LED would be off. Since it was cloudy the day this happened to me the technician and I figured my hand had something to do with the amount of light the solar panel was receiving causing it to blink.
I searched and read the other threads to see if one was a better place for this info and decided it might be better on its own and help someone in the future.