I got tired of being clueless as to how much battery life my controller has. It seemed like a pretty important aspect given that I take 20 mile rides sometimes and its just good to know.
All I did was make a cutout(eye ball it little by little with a dremel) and connect the wires to the capacitor in the picture. If you hook the meter striaght to the battery it will stay on all the time. Connect it to this capacitor to make sure it turn off when the controller is off.
Thinking of adding a momentary switch so that you can check the battery on command instead of it being on the whole ride. Let me know what you guys think or if there is anything else to add. Also wanna make my own enclosure in the future; putting together the sparkle is still not easy for me even after 5 time XD