Six Car Battery Warning Signs:
1. Slow Engine Crank
It takes a lot of power to get your car started, and all that power is produced solely by the battery. Once the car is started, the alternator keeps the car battery going by replacing the power used to start the engine and run your vehicle's electronic accessories. When you put the key in your car's ignition and turn it, the battery alone starts the engine. So if the battery is on its last legs, you may notice that the engine cranks more slowly than usual. It's important that you pick up on that warning sign, as often, you'll only get one shot at a slow start before the engine refuses to crank again. If the engine does not crank at all, the vehicle will often just make a rapid clicking sound, signaling the available power is too low to crank the engine. Have the battery tested at once and replaced if needed.
2. Issues with electrical components
In addition to powering the engine, the car battery also needs to produce enough juice to run all the various electronic components in your vehicle. In most modern cars, there are many electronic accessories including power windows, power seats, radio, windshield wipers, dashboard lights, headlights and more. All of which require electricity supplied from your vehicle's battery.
3. Dashboard Warning Light
Most cars have a dashboard warning light, usually in the shape of a battery. This will illuminate if the battery is not being replenished properly or if there is an internal problem with the battery. Similar to the Check Engine light, the battery warning light might also mean that something is wrong with the alternator or some other part of the electrical system. If the light comes on, the best course of action would be to have your vehicle's electrical system inspected by a certified professional to determine what exactly the problem is.
4. Swollen Battery Case
A car battery is basically a chemical reaction contained in a box. As with any chemical reaction, sometimes things can go wrong. When a car battery is exposed to excessive amounts of heat or cold, the flat sides of the battery case may swell or bulge. If for example the battery sits in a vehicle that is not driven for some time in the winter, the battery will discharge and may freeze. Freezing and swelling from excess heat often result in an electrically 'dead' battery that cannot be recovered and will require replacement.
5. Old Age
On average, a car battery lasts about four to five years. This average lifespan will fluctuate depending on extreme temperature exposure, number of deep discharges and whether or not it goes through full charge cycles. That being said, five years is how much life most batteries have so once you hit the 4-year mark, it might not be a bad idea to get it tested by a professional to see how much life it has left. If you are not sure how old the battery is, you should be able to find the manufacture date on the battery case.
6. Weird Smell
hen a battery has been frozen, overcharged or is shorted internally its case may vent gas. This venting often smells like rotten eggs. If you happen to detect a rotten egg scent under the hood of your vehicle, have your battery inspected as soon as possible because in addition to possibly needing a replacement battery, the sulfuric acid can eat away at other engine parts, causing corrosion, which is something you want to avoid at all costs.