It's a general consensus heat+batteries are not the best mix. When using a app like Waze, which runs the processor already, even with a 75% charged battery charging via car charger, noticed the back of the case quite warm. I just swapped cased to a Otterbox - have had the leather wallet case on my X for the last 3 months - and never noticed it hot in the back.
Anyhow, what camp do you fall in. Naked to let the heat dissipate or heat/battery not even on your radar ?
Anyhow, what camp do you fall in. Naked to let the heat dissipate or heat/battery not even on your radar ?