You can use the 50 AH battery for you Ford Icon 1.6 NXT. The recommended battery for the car is a 44 AH one, which costs around INR 4,600. The larger battery would be costly and will be of no better use. It is recommended that you go for the 44 AH only. Most of the features in the car are electrically operated and using an odd sized battery may posses risk to the equipment. You are advised to visit your nearest dealer for more information on the matter and get the correct AH value.