You either have bad batteries in your lap top.. ( is it over 2 or 3 years old and you use it unplugged and discharge the battery on it frequently) and need to replace them, or you are running a modified sine wave converter that disagrees with the transformer in your charger, or both are a problem.
Plug your laptop in at a cyber coffee shop and check the temp of the brick. If it's lower than in your RV, it's the modified sine wave inverter you are using. If it's the same temperature and still too hot, it's your battery on your laptop that needs replacing.