If you have access to a battery cycler, charge it in the proper direction for at least 16 hours and then run a discharge curve. Do this twice or three times. If the battery is withing 80 % of it's origingal capacity, you are probably okay. If you did not cause the battery to heat up a lot or build up enough pressure internally to blow the seal, you may be able to continue using them but; to be safe, I'd put in a new set of cells. PS, you must have modified your transmitter (bypassed the diode) or this could not have happened. Now you know why the diode is there.