Would it be safe ?

JohnM20

My nephew is working in China. He has just got home after nearly four months and found his car battery totally flat even though he had his battery connected up to a solar panel. The car is in his garage with the panel in the window which faces north so no
direct sunlight. A suggestion has been that he gets a smart charger and leaves this on whilst ever he is away. Would this be considered safe and would his battery be OK?