I am about to get a 2009 Kia Sorento BL diesel auto. It needs a tow bar (never had one). If I fit a 13 pin plug will it be any use to charge my caravan battery. I ask this because neither of my new cars, Peugeot 308 and Australian Ford will charge a leisure battery. They both have "smart charging" which means the alternator only supplies enough power to run what is turned on in the car. The ECU reduces alternator output to improve fuel economy. Will the Kia put some charge to a second battery?