Installing a battery meter - already have 12v accessory socket
 

I currently have a 12V accessory socket installed on my 2015 club car precedent. I would like to add a battery meter. I have found the 2 extra black and red battery wires that are available for accessories, but am not sure how to, or what to, hook up to the C terminal on the battery meter. I believe this is supposed to be hooked to the ignition switch; however, I have no terminals available on the ignition switch. It has a blue wire attached to one terminal and a green wire connected to the other terminal. There is no other terminal available on the ignition switch and I have no extra wire to connect to the C on the battery meter. How can I go about attaching a wire to the C terminal on the battery meter so that if turn off and on with the ignition switch? Any help would be appreciated.