thanks for all the info ,todays system do have smart chips in them that cuts transfer power when batteries reach full charge aint that smart of airtronics .i will take your advice on this one until the airtronics experts get back to me. thanks again but there hasnt bin an explosion yet with my transmitter i,ve used the jack in the back to charge batteries everything went without a hitch might have bin lucky but i do not see the difference like i said the jack chargers have back up power shut off for there transmitter (control)