Dear Jesse Thank you for contacting FOBO and we are sorry for any inconvenience caused. Unfortunately we regularly see new batteries that are dead in packets or discharge quickly as soon as used. We usually use and recommend Energisers/GP/Maxell brands in the market to clients as our experience is these last the longest and have nearly always proven to be reliable from new. We strongly recommended to change the sensor battery to a new battery and check the sensor's battery voltage with an ohmmeter/voltmeter if it is available and it should be more than 3v for the new battery. ( How to replace battery video link : https://www.youtube.com/watch?v=Zu_gp8oirfA ) Please let us know how it goes, should you have any issue arise, you may revert to us for further assistance. Best Regards Amir Bayati FOBO Support Team