How long is a car battery supposed to last?

I have an '07 Mustang I bought new. It has less than 27,000 miles on it. I've been informed that it needs a new battery, but it seems like this NEW battery in a NEW car didn't last very long. I've bought used cars with the original battery that lasted longer - a 3 yrs old car with over 70,000 miles on it, drove for 2 more years on the original battery. So how long SHOULD a car battery last?
How long is a car battery supposed to last?
That's ford for ya~! But no...really...if you live in an area with extreme changes in temperature as well as sea salt in the air, it's going to be a factor in the life of the battery. Mileage doesn't really matter for batteries per se as the alternator is what handles most of the load during driving.



What I would do (prior to replacing the battery) is check the cables from the alternator to the battery to make sure they aren't corroded or loose and preventing the battery from getting charged during driving.



And if you need a new battery I would suggest getting a Braille daily driving battery (not a racing battery). You'll cut about 10 pounds in battery weight and get at least 50k out of them. Excellent batteries...but you almost always need to special order them or buy them online. Believe it or not a better quality battery CAN increase gas mileage (based on weight; and electrical stability to the fuel delivery and ignition systems) but generally not more than 1-2mpg.
How long is a car battery supposed to last?
Batteries should last 4-5 years IF they're maintained properly and sometimes even longer. Keep the top of the battery clean, remove the cables and wire brush the connectors and posts at least once a year and they'll usually make it. If it is a battery with cell caps then keeping the water level above the plates is also part of the routine maintenance that's needed. And always use distilled water. A battery will usually last longer in a car that has a lot of driving. Sitting for long periods without being driven will shorten the life unless the battery is connected to a trickle charger.
As a mechanic I see lots of of bad batteries. I assume everything else is working good on your car.



7 years is a good long run on a good battery, 9 years is a record for me. But quality of batteries makes a big difference. If your warranty is 3 years 36000 miles, ford will guarantee that but no more. Also, if you let the battery drain a few times by leaving lights on etc, also can diminish battery life. In the end, it is not uncommon for a three year old battery to go bad and since your out of warranty, you'll have to buy a new one. Get whatever you want but I'd recommend the Napa 75 month battery.



Good luck
Depends on if its a maintance or maintance free Battery, If you drain the battery by leaving lights on, Stereo etc. It doesnt last for very long, Some times, The odd faulty battery gets into a brand new car, It happens. Always making sure the battery is beening charged with the cars alternator, Battery terminals are cleaned when corrioded, Then usually youre battery should last at least 5 yrs.



Good Luck.
The manufacturer wants your battery to last one day longer than the warranty. It seems like ford got it about right. Sorry.
Usually 4-5 years. But the battery in my car is 9 years old and I've never had a problem with it.
3 to 5 yrs