Lucaspod

Any idea how to tell if a laptop will charge or not in this plug, before I buy the laptop? I have two older laptops that will charge and a newer one that will not charge, in this plug, they all charge fine when plugged in to a regular outlet in my home. I would like to buy a new laptop but I need to know how to tell if it would charge in this plug before I purchase it. Any way to check the specifications of a laptop and tell if it would accept the square sine wave? thanks