How Long Should I Leave the Battery Disconnected? If you’re not sure if you have an auxiliary battery, leave the negative battery terminal disconnected for 15 minutes up to an hour-the longer the better. If you have a vehicle with an auxiliary battery, which is one that would be in an OnStar module or another module throughout the vehicle, or if it’s a hybrid or electric car, you do not want to connect the terminals together. For 2015 Models and Older, Touch the Positive Battery Terminal with the Negative Battery Terminal to Drain the Capacitors Faster On 2015 and older models, take the negative terminal and touch the positive battery terminal with it to drain the capacitors faster. This will drain the capacitors in the vehicle, which is needed to reset the car’s computer.
