I have an 06 Kia Optima. Last year, I went on vacation and left the car parked for a week and a half with the phone charger plugged in. I had always left it plugged in so didnt think it would cause a problem. Thats when it started. Every once in a while, I would go to start the car and get nothing. No noise. Nothing. It almost never takes more than three tries to get it started. I never know when it will happen but generally it happens first thing in the morning when the car has been sitting all night. About 80% of the time, it starts fine. I havent heard any unusual noises or seen any warning lights and the battery, alternator and starter were tested and are fine. For several months, it wasnt doing it and I made sure to unplug the car charger when I wasn’t using it. Then last November, I forgot to unplug it and it started happening again. I am skeptical to take it to a mechanic and end paying a ton of money and them still not be able to figure out whats wrong. Any suggestions?
My first guess would be that you have a battery going south. No longer able to hold a deep charge so when it sits with any kind of load on it, it goes flat. The time when it is starting ok is maybe after its been driven a little and the alternator has given it enough of a surface charge so there are no starting problems. If its a few years old I’d just replace it but you could have a test done to determine the actual cranking amps it has compared to what it should have.
When it doesn’t start, what do you do? Do you wait and later it starts? Or do you get it jumped from another car?
Is the accessory plug “hot” with the ignition key out?
First off, clean and tighten the battery terminals. Still happening? Ok, try an experiment, charge the battery with a battery charger for 2 hours before the first start of the day. Charge at the lowest charge rate, usually 2 amps. That should give the battery an extra 4 amp-hours of charge. Does doing that help?
If the charger is still getting power when the car is off, I would keep the phone unplugged. I will also change the battery despite the test. I have lost faith in battery testing. My last few “slow cranks” have lead me to an immediate drive to the store for a new battery and another 3-5 yrs of good starts.