Panasonic 8887549613968 CR1620 3V Lithium Coin Cell Battery

The Panasonic CR1620 is a 3V Lithium Manganese-Dioxide coin cell with a 75mAh capacity, 16mm diameter, and 2.0mm height. The lithium chemistry is the key differentiator from older alkaline coin cells: lithium maintains a flat, stable discharge curve, delivering consistent voltage through most of its life rather than gradually declining. That stability matters in microprocessor-driven devices like key fobs and fitness trackers, where sagging voltage can cause erratic behavior before the battery is actually depleted. At 75mAh, the CR1620 carries enough capacity for years of service in devices that draw milliamps or less.

This is a small purchase that delivers outsized value when the device it powers matters — a car that won't start because the key fob went dead, or a fitness tracker that stops syncing mid-workout. Panasonic's coin cells are produced to tight manufacturing tolerances, translating to a shelf life up to 10 years in storage. The main thing to get right before ordering is the exact battery designation: CR1620, not CR1616 or CR1632. The diameter is identical across all three, but the height differs, and the wrong size will not seat correctly in most devices.