Riyaz

Hi, My smart key for my Jaguar F type had a low battery sign so I changed the battery myself. Since then the key only works intermittently and its range has reduced. I often have to stand right next to the driver side front side of the door to open and lock the car. Also yesterday evening when I entered the car I couldn’t start it as it didn’t recognise the key though I got this to work eventually when I followed the instructions on screen and put the key under the steering wheel. Any idea what the issue is? i have a spare key and its battery is also low and I am scared to change it myself now in case I have the same issues !! Thanks for your help