Nobody makes a battery box that accepts more than six of these, so here's a 6x lot of NCR18650Bs, the finest commodity lithium cell manufactured today.
http://www.amazon.com/NCR18650B-3400mAh-Rechargeable-Batteries-Panasonic/dp/B00GS48XRE/You will find cells advertised with way more capacity. They are without exception Chinese fakes. Learn this the hard way if you must. No legitimate 18650 cell yet exists with a capacity higher than 3400mah.
Here's what you put them into. It's as easy as putting AAs into a TV remote:
http://www.amazon.com/Universal-Portable-External-Battery-Charger/dp/B010XU6TJC/There are ones with LED displays and shit but that sucks down power from the panel that should be going into the cells. Plainer is better in this case.
