A quick video on Pocket Operator battery life. Lasts about a week with cheap batteries and over 3 weeks with quality batteries. Not too scientific but I wanted to share! I think
PO-SBT Solder-less USB battery replacer for Pocket Operators - YouTube
Teenage Engineering Pocket Operator CA-X Generic Case (fits all Pocket Operators) - B's Music Shop
Amazon.com: Title: MyVolts Revolt 2 x AAA Battery Eliminator Compatible with Teenage Engineering Pocket Operator Synth, with Ripcord USB Power Cable - Power from Any USB Port : Musical Instruments