i have a 1991 mazda miata NA and recently the battery has been dead every time i try to go drive. I tried to just start up twice a day to keep it charged, and it got so bad that even that wouldnt work. So i did a a draw test and the multimeter said there was no draw. So i tested the battery at autozone and they said that it was a fine battery. So i decided i would try to disconnect the aftermarket radio, and that didn't work. Any suggestions?