What usb to micro usb cable would you suggest for best quality?

I'd just go with a well-known brand like Belkin, since their quality control will likely be much better than a no-name company that's probably based in China. What charging issues are you facing?
 
I'd go with Anker rather than Belkin, but B. Diddy's advice is sound.

The other problem may be that you're letting the battery drop down way below 40% most of the time, which will slowly destroy the battery.