In addition to being OEM on my 2003 Malibu, I’ve managed to drain my car battery on a number of occasions recently. I don’t know what that little green indicator on the battery is supposed to be for, but I don’t think it’s been there for a while now. (That said, if I don’t screw up, it continues to start my car just fine).
Lately instead of the ~600 km /tank I got when I first bought it, or the 500km I got last summer, I’m getting more like 300km/tank. Part of this I can blame on winter gas and the fact that I’m now commuting < 10min instead of ~30min on the highway each way nowadays, but probably not all of it.
Could these be in any way related? If I shell out $100+ for a new battery, would I be able to recoup it in fuel costs? Or if it still turns the engine over is it for all intents and purposes “good”?
Not really the car electronics (even if they did effect mileage in a noticeable way) don’t run off the battery while operating, but the generator, the battery only starts it.
You can actually take the battery out of a running car and the car will stay on. As said above, the battery is only needed to start the vehicle and run the electronics components such as the radio and lights when the vehicle is not running.
2003 this is 2009. I would change the battery before you get stranded. With a bad battery you DC buss voltage is going to varry and may have an effect on the electronics.
A battery that won’t hold a charge acts like a large load and the alternator will be working constantly to try to charge it, which will result in a very slight (possibly unmeasurable) reduction in gas mileage as well as shortened alternator life.
I would disagree with the statement that the alternator/generator runs everything when the engine is running. Normally, everything still runs off the battery and the alternator keeps the battery charged. After the alternator replaces the energy used to start the car and if you’re not running something that’s a high draw like the lights or the defroster, the alternator mostly freewheels and only occasionally kicks in to “top off” the battery because it’s not good at running constantly at low loads. If you run your car without a battery, it forces the alternator to run all the time, which can make it provide too much current to the electronic components which can cause expensive problems.
Modern car batteries are different than batteries of the 70’s. They are more powerful and smaller. This is done by using more plates and spacing them closer together. They last 4 to 5 years but they don’t fade away slowly, they go tango uniform in the middle of the mall parking lot at 9 pm.
I wouldn’t expect it to hurt your fuel mileage but you’re about to call a tow truck.
I wouldn’t discount the season and your new commute being the cause in your drop in mileage. In less than ten minutes, your car is probably just warming up by the time you shut it down again, which really sucks up the gas.
I would definitely consider switching out the battery anyway just to avaoid being stranded.
Yes it could if it affects the processor during start up which is a heavy draw. The same for a dead battery. The brain box for the vehicle can be resetting to defaults when this happens.
By the way, don’t get a cheap battery from Advance Auto or somewhere. Get a factory one (your Chevy one lasted 6 years, that’s darn good. My Ford OEM battery lasted that long too.)
I’ve got a 2002 Saturn, and I just went from an 80 mile/day freeway commute, to a 8mile/day street commute. I’ve seen just about the same thing.
Summertime, long commute, I would get 30mpg.
Wintertime, long commute, I would get about 26mpg. (In Minnesota, they change the gasoline mix in the winter)
Now, I’m seeing about 20mpg, with a short wintertime commute.
Sounds like your numbers are in the same ballpark as mine.
