My optima hybrid has about 130k miles on it and works perfectly except for this one odd issue that I nor the dealer can figure out. Every so ofter (about once a month), the car will for no reason act as if the 12v is totally dead. However, I do not believe that this is the case. My jumper box has a volt meter on it and before I energize the jumper cables I read the voltage from the battery and it is always around 12.4 to 12.6 volts. However, whenever I power on the jumper box, the car instantly jumps to life and blares the alarm. Then it behaves normally as if nothing has happened. No lights on the dash, no errors from the OBD port as stated by the dealer. Does anyone have any ideas? The dealer doesn't seem to believe me (they think I am some kind of ditz) and just keeps wanting to charge me $30 to replace the key fob battery. They say nothing is wrong with the car, the main pack, or the 12 volt. Has anyone experienced such an issue? Could it be a drain protection feature that is automatically activating because the car thinks there is an abnormal draw somewhere?