Great that it works for you. I am building a 2x 18650 batt box and wanted 6v. I did go to rat shack and bought some of the diodes you are using. My 18650's in series at full charge hit 7.9-8v, I installed 3 diodes in series and it only dropped to 7v for me. I would need 1-2 more they are bigger than they look so its prob not gonna work for me. But great idea, and great job on yours!