It is important to use an Alkaline battery in the Alco-Sensor III. Do not use “Heavy Duty” or “Super Heavy Duty” or rechargeable batteries. Rechargeable batteries do not drain the same as Alkalines and can cause errors in the Alco-Sensor III.
“Heavy Duty” batteries are Carbon Zinc batteries and are most useful for low drain or infrequently used devices. Alkalines are used for high tech and high usage devices such as the Alco-Sensor units.