Q: We went on vacation for 16 days and left my 2017 Malibu at a nearby long-term parking lot. When we got back, we discovered the car battery was dead. I was told by OnStar and the dealer that the Malibu battery can go into hibernation after 10 days. After 15 days, it is possible to completely drain. This doesn't sound right because there could be many occasions where my car won't be driven for 2 weeks. Is this a defect? I can't believe a car battery can completely go dead in 2 weeks. They explained that there are so many electronics being maintained while the car is parked, that the battery will slowly drain and it needs to be started during that time to keep it charged. I towed the car to the dealer the next day and they recharged the battery and it is running normally. I worry on my next vacation or business trip I will return to a dead battery, again. Is the only option to disconnect the battery while away on vacation for two weeks or more? Is this normal for new cars?
�� Terence C.
A: This is tough one because I'm not sure what the outside temperature may have been as this issue arose, and how far you typically drive during a standard trip. When a vehicle is parked, a tiny quantity of electricity is consumed to maintain memories such as the clock, radio stations, emissions component and system test results, user selected settings, and other functions. Your body control module is supposed to go to sleep after being parked for a while, but also needs to be ready to spring into action the instant a door handle is pulled. I wonder if the rumble of the airport could be causing occasional awakenings.
A typical vehicle's parasitic drain may be about 30 milliamps. Depending on the battery's state of charge and condition, and outside temperature, and the number and type of control modules in use, battery standby time is perhaps 15 to 25 days. Cold weather degrades battery performance and increases starting effort, taking folks to the lower end of the range. Short trips may also not allow sufficient charging time to return the battery to a full state of charge before shut-off.
It's possible your Malibu has an unacceptable parasitic drain, perhaps due to a module failing to go to sleep, or the "afterblow" climate control function being selected (runs the HVAC blower intermittently after shut-off to mitigate mold odors) _ this knocks the battery a bit. Parasitic drain can be tested, under the new car warranty, if the dealer is willing to expend the effort. Hopefully if there was a fault, it would be active at the time of testing, and confirmed.
There is some confusion or misinformation regarding your mention of "hibernation." It's your 4G LTE-based 10th-generation OnStar hardware that goes into hibernation after 10 days, not the battery, and that reduces parasitic drain. They are correct about the other information.
For folks who may be parking their cars and trucks beyond a week, a portable solar panel such as the Coleman 3.5 watt solar 12V battery trickle charger with OBD-II connector can keep the battery full if placed on the dash, oriented in a sunny direction. I mentioned this particular unit because it has a connector that plugs into a 1996 or newer vehicle's data connector, which is "hot at all times", as opposed to a typical solar panel that plugs into the accessory socket, which may not be active on many vehicles when parked. Don't disconnect the battery! There are too many things that need to relearn behavior and it's inconvenient to re-enter needed information.
