Be honest we all need one of these in our cars, the FKANT Waterproof Solar Charger houses a massive 16,000mAh battery pack and it comes with a convenient LED flashlight.

The FKANT Waterproof Solar Charger claims to be waterproof up to 3 feet,  its LED light supports 3 modes (Normal / SOS / Strobe) and FKANT power banks protect itself from overload, overvoltage, overcurrent, overcharge, over-discharge, over-heating. 

This device is handy and what I consider a really good buy, well so would others as it got 4.6 out of  5 on Amazon. Go check it out.Maybe you could buy it for your HTC U11 

 

Check Amazon$39.99