To drop your voltage you could always try two diodes in series. Silicone diodes have a 0.6V drop across them so two in series = 1.2V, that takes your 7.4V down to 6.2V. Will also then protect against (your "friend") connecting the battery in the wrong way..
I also use diodes in series + small globe to discharge RX packs without going too low in voltage
