This Instructable applies to my car, but with all of the modern electronics running in the background on today's automobiles, your car may have this problem, too. This Instructable tells about the solution to my problem, but may be helpful with a similar problem on your car, too.
Materials needed for this Instructable--none
- Multi-meter with an ammeter scale capable of reading up to about three amps.
- 8 mm socket wrench and ratchet
- Spring clamp for connecting a small alligator clip to the battery post
Step 1: How Much Is the Current Draw?
With everything "off," the doors closed for a few minutes so all dome lights have gone "off," and the key removed; there is a current draw of 470 milliamps, or nearly half of an amp. At a recent visit to the nearest dealership for routine warranty service I asked about this. I was told that is normal. If I am concerned, I should connect a trickle charger when I will leave the car unattended for more than a week. See the second photo. This is a battery conditioner we bought a few years ago for another purpose. I could mount it in the engine compartment and connect an extension cord to it when we will be gone for more than a week.
My question of the dealership was, "What do I do if I need to leave the car in an airport parking garage for a couple of weeks?" There are no electrical outlets in the parking stalls at any airport garage I know.
Step 2: What the Dealership Did Not Tell Me
The graphic is a page from my owner's manual in the section on fuses. It describes a memory fuse that can be pulled when leaving the car unattended for long periods of time in order to avoid a dead battery. Even if I had read this, I am not sure I would have remembered it or that I would have made the connection in my mind. From doing searches on the Internet, particularly on an owner's forum, I suspect this information has escaped others, too. But, the search for a solution to my problem can be more complex and confusing than it would seem. Some have had the dead battery problem because of a bad cell in the battery, faulty battery cables, a bad diode in the alternator, or even a problem in the car's radio. A dead battery after a few days has been a problem on several makes of car, not just my 2012 Hyundai Sonata.
UPDATE: October 9, 2012-- A friend who owns a 2013 Sonata spoke with his dealer in a different state and city. He did not let the dealer know he is aware of the memory fuse. He asked about the battery going down in a short time. The dealer said new cars of all makes and models have so many electronics items running in the background, even when everything is "off," that the battery on newer cars will go down fairly quickly. When my friend asked what to do, the dealer advised buying a trickle charger. Then my friend asked what he should do if he needs to leave his car at an airport lot for a few weeks. He got only a blank stare from the dealer and no answer. Then my friend led the dealer a bit and asked if there would be any kind of fuse that could be pulled to reduce the current draw. The dealer said he did not know of any!
Step 3: Fuse Information With Photos
Step 4: Find and Pull the Fuse
There are two fuses in this holder. To remove the holder from the car, squeeze it under the extensions you grasped on each side and pull. This releases two small catches. Each fuse can be removed separately from the yellow holder and replaced as necessary.
Step 5: Big Difference
Check the owner's manual on your car to see if it has a fuse like the one on my Hyundai Sonata, especially if you have had a dead battery problem after only a few days.