Apple advises against using bitterant-coated replacement batteries for AirTag
Apple's AirTag object trackers released earlier this year are expected to last at least a year on the factory-issue battery and users may not need to look for replacements soon. However, when they do, they must steer clear of bitterant-coated ones. Apple recently issued a warning to customers in a support document for the AirTag, first reported by The Loop. Here are more details.
Apple's support documentation for the AirTag released a couple of weeks ago details how users should replace a battery in their AirTag. The object tracker uses one standard CR2023 type 3V lithium battery. This battery is widely available but those that use a bitterant coating may not work "depending on the alignment of the coating in relation to the battery contacts," said Apple.
As the name suggests, the bitterant coating is a thin, invisible layer some manufacturers coat their batteries with so that the batteries taste bitter and children are discouraged from swallowing them by accident. Duracell explained that hundreds of lithium coin batteries are ingested by children every year due to their small size. Last year, the company started using Bitrex bitterant to coat batteries.
Duracell claims Bitrex layer is completely non-toxic if ingested, even though it's reportedly the world's most bitter substance. The problem is that if lithium is ingested, it could prove fatal for humans. With children, there is the added risk of the battery getting stuck in the esophagus. So, you should take care kids don't ingest these batteries and also avoid using them with AirTags.
The Panasonic battery that comes factory-installed on AirTag should last a year. Once it runs out and you've identified the correct (uncoated) replacement, press down on the steel side of the AirTag and rotate counterclockwise till the cover pops off. Then replace the battery (positive side up). Line up the AirTag's three slots with the steel cover's tabs and twist clockwise till it locks.
Once the steel battery door is securely reinstalled on the AirTag, the device should beep once to indicate that the battery is connected. The Apple Find My app displays each of your AirTag's battery levels using a battery icon under the name of each AirTag. Apple explained that in case the battery is due for replacement soon, you'll see a Low Battery banner.