u/Empty_Finger_2959

My dc to dc charger has been draining my battery and I’m not sure if it’s my d+ wire or not. I’ve used my multimeter and see 0v when the car is off and 12v when the car is on with the fuse tap that I was previously using but my battery was still discharging with the car off. I have since disconnected everything… Which fuse do you all recommend to tap or what else can I do to diagnose the problem?