Typically, they will last approximately 2-4 weeks, depending primarily on the amount of driving the subject drives. When the vehicle tagged with a named into a covered structure, such as a parking garage, it will have difficulty triangulating its location, which will run the battery down quickly. Once the battery level reaches near 25%, we recommend scheduling a swap of the dead device with a fully charged device. We will try our best to remind the client of the dwindling battery in the GPS unit!