I vape my Pico (and all others) at 10 watts with the LG HG2 and the Sony VTC6. Both provide similar run time. All the batteries KenD mentioned are the better choices for most any mod for low or high watts.
The good part is the high MAH ratings on those. You get high amps and the 3000+ milliamp per hour rating gives you longer runtime. There are lots of 20A batteries with much lower MAH ratings.