I assume the USB beverage warmer reduces battery life to approximately 10 minutes :-) > http://www.amazon.com/New-Coffee-Beverage-Warmer-Heater/dp/B004P15KAK/ref=sr_1_7?s=pc&ie=UTF8&qid=1447425044&sr=1-7&keywords=usb+beverage+warmer > (good for winter)