our vehicle relies on the battery under the hood for everything—from running your radio to starting your engine. The battery is the most influential piece of equipment your car needs to drive down the road, because you can’t go anywhere if your battery can’t start your engine.
If you’re left wondering what causes your car battery to die, you’re not alone. And the answer to this popular question includes a variety of different reasons. Originally posted in 2018 and updated in 2019, our auto repair experts discuss top reasons car batteries die, signs to look for that indicate your car battery is on its way out, and how you can prevent your car battery from dying.
TOP REASONS CAR BATTERIES DIE
There are several factors that can cause a dead battery. The following are the most common issues our customers face.
- OLD BATTERY (OLDER THAN 4 YEARS): THE OLDER YOUR BATTERY IS, THE MORE LIKELY IT IS TO MALFUNCTION. IF YOU SUSPECT THAT YOU’RE HAVING BATTERY PROBLEMS DUE TO ITS OLD AGE, CONSULT WITH US TO GET A REPLACEMENT.
- CORROSION: AFTER A WHILE, THE METAL TERMINALS ON YOUR BATTERY WILL OXIDIZE AND CORRODE, CAUSING THEM TO WEAR OUT. THIS PHENOMENON WEAKENS THE CONNECTION BETWEEN YOUR BATTERY AND THE ELECTRICAL SYSTEM. YOUR BATTERY WON’T BE ABLE TO SUPPLY AS MUCH POWER AND WILL AGE MORE QUICKLY DUE TO THE INCREASED RESISTANCE BETWEEN THE BATTERY TERMINAL AND ELECTRICAL LEAD. TAKE A LOOK AT YOUR TERMINALS, AND IF THEY ARE STILL IN GOOD SHAPE, SIMPLY CLEAN AND TIGHTEN THEM TO ENSURE THE CONNECTION IS STILL SOLID.
- LEAVING LIGHTS ON: MOST MODERN CAR MODELS DO A GREAT JOB OF WARNING YOU WHEN YOU’RE ABOUT TO LEAVE YOUR CAR WITH THE LIGHTS STILL ON. HOWEVER, SOME OLDER MODELS DO NOT HAVE THIS CAPABILITY. YOUR HEADLIGHTS USE CONSIDERABLE BATTERY POWER—A CURRENT YOUR BATTERY CAN SUSTAIN FOR ONLY A SHORT PERIOD OF TIME. IF YOU ACCIDENTALLY LEAVE YOUR LIGHTS ON OVERNIGHT, YOU’LL FIND THIS OUT THE HARD WAY WHEN YOU DISCOVER YOUR CAR WON’T START THE NEXT MORNING. BE SURE TO ALWAYS TURN YOUR LIGHTS OFF BEFORE LEAVING/LOCKING YOUR VEHICLE.
- EXTREME WEATHER: BATTERIES ARE DESIGNED TO WORK BEST IN A COMFORTABLE, MODERATE TEMPERATURE RANGE. HOT AND COLD TEMPERATURES CAUSE STRAIN ON BATTERIES. IF IT’S TOO COLD, THE ELECTRICITY CAN’T PASS THROUGH THE SYSTEM AS EASILY, MAKING IT TOUGH TO OUTPUT ENOUGH VOLTAGE TO START YOUR CAR. IF IT’S TOO HOT, THE BATTERY WEARS OUT MORE QUICKLY. THE BEST WAY TO PREVENT EXTREME WEATHER FROM WREAKING HAVOC ON YOUR BATTERY IS TO PROTECT IT FROM THE ELEMENTS IN A GARAGE OR PARKING STRUCTURE.
- ALTERNATOR PROBLEMS: YOUR BATTERY IS NOT A CONTINUAL SUPPLY THAT RUNS OUT SLOWLY OVER TIME. USING YOUR ALTERNATOR, YOUR BATTERY DISCHARGES WHEN STARTING YOUR CAR AND RECHARGES AFTERWARDS. THE ALTERNATOR, WHEN WORKING PROPERLY, TAKES THE ENERGY YOUR ENGINE PRODUCES AND TURNS IT INTO ELECTRICITY USING A GENERATOR THAT FEEDS BACK INTO YOUR BATTERY. WHEN YOUR ALTERNATOR STOPS WORKING PROPERLY, YOUR BATTERY WILL NOT BE ABLE TO CHARGE, AND WILL DIE QUICKLY AND OFTEN. ALTERNATOR ISSUES ARE BEST SOLVED BY CERTIFIED PROFESSIONALS. BOOK AN APPOINTMENT AND OUR EXPERT TECHNICIANS CAN HELP.
IS MY CAR BATTERY DYING?
The good news is, modern batteries are made to be extremely strong. They provide a lot of turnover power, even in the cold, up until they are no longer capable of working. The bad news is, in the past, when your battery was weakening, you would have plenty of warning. You’d crank the key and your car would turn slower and slower before finally firing. This allowed you to get a new battery before it stopped running completely. Unfortunately, because today’s batteries are strong and run right until they give out, you don’t have the same warning system as before.
If you’re worried that your battery is nearing the end of its life, try these at-home diagnostic tests to be sure:
- LISTEN CAREFULLY TO YOUR ENGINE AS IT TURNS OVER EVERY MORNING. IF THE CRANK SOUNDS DIFFERENT OR SLOWER THAN NORMAL, YOUR BATTERY MAY BE ABOUT TO DIE.
- ATTEMPT TO TURN ON YOUR CAR’S ACCESSORY MODE AND OPERATE YOUR WINDOWS (OR ANOTHER HIGH-POWER FEATURE). IF YOUR WINDOWS MOVE SLUGGISHLY, A DEAD BATTERY MAY BE IN YOUR IMMEDIATE FUTURE.