I drink decaff coffee all day so I planned to keep coffee in the Tumbler all day while sporadically on and off the charging coaster. Unfortunately, the charger is too slow. You can't quickly add some charge to the tumbler when at your desk before needing to walk away with your coffee. While warming coffee, the charger only maintains the current charge. With no coffee, the battery takes hours to charge.

At least for my use case, I find the battery dead often. The non-insulated mug then becomes no different from a paper cup. Unable to keep any heat in.


I'm returning this. I'll just get a vacuum sealed mug and live with a bit hotter than I like coffee in the beginning but never too cold (the worse end of the temperature range for me). It'll be leak proof as well which the sipping lid for the Ember is not.