Cold temperatures slow down Pixel 2 XL charging despite misleading notification4
So far, this behavior has been seen on the Pixel 2 XL and not the Pixel 2. This is an issue that is problematic on two levels. One, a Pixel 2 XL battery cooled to less than 68 degrees fahrenheit takes a much longer time to charge than usual, even though the cell shouldn't be affected so much at that temperature. More on that below. The second issue is that while this slow down is happening, the phone still shows a notification that it is "charging rapidly", which is certainly misleading users.
Google is reportedly investigating this issue. According to some experts, Li-ion cells (the kind found inside a smartphone) charge best within a range of 10°C to 30°C (50 degrees to 86 degrees fahrenheit). That would mean that there shouldn't be such a huge slow down in the charging of the battery powering the Pixel 2XL until the temperature of the battery drops another 10°C.
As soon as we hear something from Google about this, we will pass it along to you.