i haven't ruled out the information "the same charger which took 7 hours to charge 17%" means that it was in fact turned off, not connected properly, or otherwise not charging at all.
are you suggesting he buys another tower, connects that in parallel (plggued in to the wall) and uses that one for the charger, the increased parallelness increasing available current? its an interesting point.
i was going to suggest the towers dont have heavy duty cables, so restrict the...