Well, pretty easy considering the at 150 Mah lipo is a extremely small battery that is used for micro's. The harness I use for charging has about 14 different wires with different size connectors to accommadate practically any RC battery used today. When I was flying last sunday I had charged the 150mah at the field, but never used it. I decided at the field just to leave it attached for the ride home. Anyway, forgot all about leaving it attached and when I hooked up to charge the tx, the 150 was simply buried under all the harness wires and I just didn't see it. Had it been a 300, 600 or 800 I would've noticed it for sure. I do not expect to win "RC battery charger of the year" for this incident and I could've as well saved my self the embarrassment and not posted any info. But feel that mistakes are just as important as no mistakes. I'm sure everyone that has read these post will double check (including me) before they charge their batteries next time. Pic of charge lead I use is attached