If your car won’t start and/or the electronics are malfunctioning, your battery could be to blame. But if you’re not sure, don’t sweat. There are a few telltale signs of a dead car battery, and they’re easy to recognize if you know what to look for.
This article lists all the signs your car’s battery is dead. Keeping to learn how to spot those signs, how to replace or fix a dead battery, and how to take care of your car battery so it lasts as long as possible.
Signs Of A Dead Car Battery
A failing battery’s symptoms might be attributed to problems with other components, such as the starter, alternator, or other electrical parts. However, for our purposes here, we will assume all the listed symptoms are battery-related.
Although a new battery failing is not unheard of, the older your battery, the more likely one of our warning signs below indicates it is failing or dead. Signs include the engine won’t crank, or it’s slow to start. Read on for more.
#1. A Sudden, Slower Start.
When temps drop below 20 degrees, generally any car’s starting cadence will slow down. Get below 0 and it gets even slower. If you notice this behavior suddenly and the temperature hasn’t dropped – a slow, dragging start suddenly begins, get your battery tested as soon as possible and don’t ignore it. Eventually, the car will not start.
If a slow-starting battery seems able to take a charge and test fine, it’s likely that a parasitic drain, or draw is discharging the battery while the vehicle sits, and the electrical system will need to be looked at.
#2. Headlights And Power, But No Start.
Your lights work, the radio works, but you get a click or buzz once you hit the key. Or, your headlights are very dim. The purpose of the battery is to crank the engine by providing a full dose of high-amperage power to the starter. When the battery is low, it cannot deliver that power but often can still supply enough power for lights or accessories, that don’t require as much amperage.
Keep in mind, that jump-starting the car in these situations should only be done in an emergency. Get the battery tested as soon as possible, and do not rely on the alternator to charge the battery back up!
#3. No Radio.
Your radio doesn’t turn on. Don’t mistake it for a minor inconvenience. When the ignition is in the ON position, the battery will run the radio, windshield wipers, and headlights, among other electronic devices. If these flicker or dim before starting, your battery charge is weak.
#4. The Battery Case Is Swollen.
If your car has recently endured a hot wave or a cold snap, it’s a good idea to pop the hood and take a look. The battery case can swell when exposed to extreme hot or cold temperatures, and this can lead to an “electrically dead” battery. If this happens, the battery cannot be recovered and will have to be replaced.
#5. Odd Smell From Your Battery.
The stink of sulfur is a sign that your battery acid is leaking. Leaking battery acid is one of the top signs a car battery is dying. A dying lead battery will produce hydrogen sulfide gas, which smells like something between rotten eggs, a sewer or well water.
#6. Your Battery Is Old.
Your battery is old. The average life span of a car battery is typically between four to six years. At around the four-year mark, you should pay more attention to it. Have a technician check to see how much charge it has.
#7. Check Engine Light Flashes.
The check engine light flashes or stays on constantly. Generally, this light identifies serious problems in your engine that will require costly maintenance. But you may get lucky and discover that it’s only your car battery that needs replacement.
Does your car have a battery dashboard warning indicator? Generally, it’s in the shape of a car battery and comes on when the battery is not charging properly or has an internal problem.
IMPORTANT: When this light comes on, don’t ignore it! Have your battery professionally inspected as soon as possible.
#8. Corroded Battery Terminals.
One of the main reasons why car batteries die is because of corrosion. Battery acid will leak out at the connectors, then harden and reduce the amount of contact between terminals and connecting points. This reduces the battery’s ability to recharge via your vehicle’s alternator.
Battery corrosion will be quite visible to the naked eye; the terminals will be caked with blue-green powder or flaky residue. In some instances, cleaning your car battery terminals with a dry rag of toothbrush can extend the life of the battery. However, if you notice battery connector corrosion, it’s usually best to consider buying a new vehicle battery, just to be safe.
#9. The vehicle Starts, Then Dies Immediately.
This is a very strange issue that can indeed happen on certain makes/models of vehicles. The battery will have enough voltage to start the vehicle, but then it immediately dies and will not idle. If you encounter this issue, there are a multitude of things that could be wrong, but doing a simple battery check is the first and easiest place to start.
The basis behind this is when a battery fails, it can cause interruptions to the constant signals it sends to the ECU. Then if the battery can muster enough might to start the car, the sensors controlling engine idle, speed, and fueling have already lost signal, and the car immediately dies.
#10. Electrical Issues.
General electrical problems are a major sign of your battery dying and could affect pretty much your whole dashboard or electrical system.
These are some tertiary signs of a bad car battery:
- Your heated seats aren’t coming on.
- Your dashboard or radio is working sporadically or not working at all.
- Your dashboard lights are blinking, flickering or not coming on.
- Your electronic windows aren’t working. Your sunroof may also be affected.
- Your cell phone isn’t charging when you plug it in.
Of course, each of these alone might not be a guarantee of a bad battery; it’s best to check under the hood.
What to Do When Your Car Battery is Dead?
These tips may get you back on the road, but you may also need to replace your battery or check for other electrical system problems like a failing alternator.
Jump-Starting Your Car Battery
The simplest way to bring your vehicle back to life is to jump-start the battery. This involves either sharing the electrical power from another automobile through jumper cables or using a portable jump pack to help give you enough juice to start your vehicle.
The portable jump-starter solution is sometimes the easiest. Most have electrical leads you need to attach to the dead battery, which will provide enough spark to restart your car. Some, but not all, are able to supply power to completely discharged batteries. Most require some voltage to operate, even if that’s not enough to start the car.
Chargers that plug into a 12-volt outlet inside your car are simple, but they’re not a quick solution, like jump packs or jumper cables. Those types of chargers — often called cigarette lighter jump starters — function more like a trickle charger, supplying very low amperage through the light duty wires (when compared to the wires attached to your car battery) that charges the car’s battery slowly.
Alternatively, if you’re at home and you have time, a battery charger is a viable solution for addressing a dead car battery. The cheapest, and most basic, models will plug into an ordinary wall outlet and can recharge a car’s battery in a few hours. More expensive models may even have an “engine start” mode.
How to Jump-Start Your Car with Jumper Cables
Here’s a little refresher for the old timers — or a quick introduction for new drivers — on how to jump-start a dead battery on your car.
When Jump-Starting, Follow These Tips:
- Get both cars ready. Place each car in park or neutral, turn them off, pull the parking brake and pop the hood. The cars should not be touching.
- Your jumper cables have 4 sets of clips, or alligator clips. Red is positive and black is negative. Here’s the correct order for your jumper cables:
- RED to DEAD: Connect the red clip to the positive terminal on your dead battery.
- RED to DONOR: Connect the red clip to the positive terminal on the donor vehicle’s working battery.
- BLACK to DONOR: Same car! Connect the black clip to the negative terminal on the donor vehicle’s working battery.
- BLACK to METAL: Back to the dead battery. Connect the black clip to an unpainted metal part of the dead car (like a bolt or bracket) that is not directly next to the battery.
- Start the engine of the working car and let it run 1-2 minutes.
- Start the car with the dead battery and allow it to run 1-2 minutes so it can recharge.
- Remove the cables in reverse order and start driving your resurrected vehicle for 30 minutes so that it can recover for next time.
When Jump-Starting Doesn’t Work … Consult an Auto Expert.
If you’ve tried the jump-starting routine and are still unable to get your car to start, it might mean that your battery is completely dead. Have a mechanic, an auto shop, or an auto parts store test the battery to see if it needs to be replaced entirely. Auto batteries have a typical life of three to five years, after which they can no longer hold a charge, and yours may have reached the end of its journey.
A car battery test result will also let you know if there may be another problem. The alternator — the mechanically driven electrical generator attached to your engine — may no longer be able to generate enough power to keep your car going and your battery charged.
If you’ve also been experiencing dim headlights, slow-to-work accessories, or the smell of burnt wiring, it might be shot. A mechanic can run a quick test and see if the car battery needs replacement.