leaving radio on when turning off the engine drains the battery

sdseabreezesdseabreeze Member Posts: 9
Leaving radio on when turning off the engine drains the battery, eventhough the radio is off?

Has anyone heard or know of this? What I notice is that if I leave my radio on when I turn off the engine, the next day, the battery is drained and I can't start my car. It sputters and tries to turn over but cannot start. Again, this morning I went out to start my car and it won't start, then I remembered I left the radio on when I turned off my car last night. Finally, it got a kick start and the engine started and my radio began playing. I turned off my radio, turned off the engine, started the car and it started right up.

My sister had same problem in her 2005 Hyundai Tuscon.


  • mpuzachmpuzach Member Posts: 635
    I highly doubt that the circumstance you describe would actually drain the battery.
  • somedai1somedai1 Member Posts: 416
    that would be a major design flaw - are u sure you didn't leave a door open or something?
  • eyoeyo Member Posts: 24
    I never turn off my radio when I stop the car. After 70k kilometers and 2 years I still have the factory battery working without a problem.
  • wahldowahldo Member Posts: 1
    I have a 2007 Hyundai Sante Fe which I purchased preowned. It currently has 8,000 miles. In the last month the battery has died twice. The dealership says that it is not my battery or alternator and that I must be leaving the lights on, but I know that I do not leave the lights on. I do leave my radio on, I'll have to try turning it off.
  • tidestertidester Member Posts: 10,059
    Leaving the radio on should not drain the battery unless the radio is defective. Normally, power to the radio is shut off when the ignition switch is turned to off so either the ignition switch is malfunctioning or there is a short circuit associated with the radio.

    tidester, host
    SUVs and Smart Shopper
  • fromzy98fromzy98 Member Posts: 1
    I bought my 2008 Santa Fe last week. When the dealer brought me out to show me all the features of the car, it wouldn't start. He then said that he thought the mechanics probably left the radio on when they they were getting it ready for me.
  • somedai1somedai1 Member Posts: 416
    i agree - radio is key on power only - shut off the car - no power to radio - you need to make sure you are not leaving the tailgate ajar... - i did it twice - closed it but it wasn't closed properly - killed the battery 2x
  • jntjnt Member Posts: 316
    I messed up in typing so here is correction:

    Whenever you turn off the IGNITION to the car, the normal radio would go to SLEEP and uses very little power (<1mA in SLEEP mode vs. 2A in OPERATING mode).

    So assuming your battery has 200 Amp Hour capacity or 200,000 mA hour. It would take 200,000 hours for the battery to be drained by the radio in SLEEP mode. That is about 347 days.

    Now if the radio is not going to SLEEP and stays in OPERATING mode with IGNITION off, it would draws 2A. Then the battery will be gone in 100 hours which is less than a week

    But there are many electrical modules inside the car which also draw battery power. Any of them, if not working properly could drain the battery.

    Another thing: for people who only drive 2-3 miles each day, then the battery may not be recharged enough and eventually it would lose its energy. In that case, take the vehicle out for a long distant driving once in awhile to replenish the battery, lubricate the system,...
  • steverstever Guest Posts: 52,457
    I'll zap the dupe.

    For future reference, after posting, you may edit your post for 30 minutes.
  • jntjnt Member Posts: 316

  • boeing1boeing1 Member Posts: 3
    the first thing i would do is check the battey its probably no good
  • rfaronsonrfaronson Member Posts: 1
    I've had this problem with my 2004 Accord for almost 200,000 miles. All night long, the radio console flashes on and off even though the key is in my pocket. If I leave the radio/CD on, then it also plays for about half a second. A high end stereo repairman said it was a known problem to him caused by bad solder on that Accord, and resoldered all the places he saw where it had run. That fixed things for about six months (he did warn me it might start happening again). Recently it flashes so much that if I leave it for 4 or more days, it won't start. A friend suggested removing the Radio Fuse if I'm going out of town. Will that work? Where is that fuse?
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