Signs of a bad car battery are far from fully known to experienced and novice drivers. For most, the main symptom of a discharged battery is a problem starting the engine in the cold season. This is true, but in fact the battery is not only responsible for setting the motor in motion. Any battery performs 3 functions:
- starts the starter, which turns on the engine;
- feeds the on-board electronics when the engine is off;
- helps the generator if it can’t handle the load.
The battery charge must be maintained at an optimal level, otherwise it will not perform its basic functions. A discharging battery can still cope with some tasks, but it does it an order of magnitude slower and worse. To avoid critical situations, you need to understand the main signs of a dying car battery. PAK specialists will talk about 9 common situations in which the battery has sat down and requires prompt replacement.
1. Engine is hard to start
A dying or non-working lead battery will definitely show itself at the moment the engine is started. The battery is responsible for turning on the starter, which begins to turn the crankshaft (one of the main components of the motor). Under normal conditions, the car should start within a few seconds after turning the key or pressing the start button. If there is a problematic battery, the car will start differently:
- it takes longer to launch, regardless of weather conditions;
- when starting the car, the shaft starts to rotate more slowly than usual;
- when turning the key or trying to press the button, private clicks of the starter relay are heard.
The reason for the appearance of such symptoms is most likely a discharged or faulty battery. If even a slight suspicion is found, it is recommended to check the battery in order to charge or replace it if necessary.
2. The battery charging indicator is constantly on
The panels of modern cars are equipped with a special control indicator showing the battery status. The signaling device has the form of a light bulb with a battery depicted on a red light filter. The indicator lights up when the ignition is turned on and goes out immediately after starting the engine. In some situations, the light does not turn off, but is constantly on. This indicates a problem with the alternator or battery.
Battery problems can also be suspected if the Check Engine spontaneously lights up on the panel (problems in the engine operation system). When there are no other noticeable deviations, but the indicator continues to burn, you should promptly apply for a diagnosis.
3. Mechanical damage to the battery case
The internal structure of the batteries is represented by a set of lattice lead plates, which are coated with a special active substance (spread) and immersed in an electrolyte (an acidic conductive liquid).
As a result of mechanical impact (shocks, strong shaking due to poor fixation), the battery case is deformed, the outside is covered with chips and cracks. This contributes to serious internal damage (shedding of the spread or complete destruction of the plates), can lead to electrolyte leaks or frequent micro circuits. The presence of any deformations is a dangerous situation in which urgent disposal of the battery is required and replaced with a new one.
4. Battery swelling
Some signs of a bad battery can be identified by a simple visual inspection of the device. Body swelling is one of them. Chemical reactions are constantly taking place inside the battery. For their implementation, optimal conditions must be observed, especially with regard to temperature.
The effects of heat and frost have a bad effect on the electrolyte in the banks (cells) of the battery:
- when overheating occurs inside the battery, excessive gas formation occurs, which inflates the case;
- in severe frosts, the liquid hardens and deforms the body (subject to long downtime on the street or in an unheated garage).
A swollen case is a clear sign of a dead battery. You won’t be able to save him.
5. Dark electrolyte color
Chemicals deposited on lead plates, due to age, temperature changes or mechanical damage, can crumble and settle in the electrolyte. Accumulating, the destruction products begin to change the color of the conductive liquid from transparent to darker (from gray to black). If this symptom is detected, you should quickly replace the electrolyte or buy a new battery. Riding with broken plates is dangerous, explosion on the move is possible.
6. Putrid smell from battery cans
If any problems occur, foreign, unpleasant odors may appear inside the battery. Possible causes of a putrid odor include:
- plate closure;
- freezing or overheating of the electrolyte.
All these malfunctions entail the release of gas, which smells like rotten eggs. At the initial stages, the aroma will be heard only from under the hood, and with the aggravation of the situation, it will begin to appear in the car.
7. Low electrolyte density
A full battery charge takes about 8-10 hours. After completing the procedure, you need to check the level of electrolyte density. The parameter must exceed the value of 1.25 g/cm 3 in each cell. Even if the density of the conductive liquid, according to the test results, is reduced in only one bank, it is dangerous to drive with such a battery. Low electrolyte levels combined with other “unhealthy” symptoms are clear signs of a car battery failure.
8. Auto auxiliary systems do not work
The battery powers the auxiliary modules of the machine when the engine is off. This includes headlights, power windows, climate control, multimedia, security unit and other related systems. When the battery is dead or in a highly discharged state, these modules begin to fail or do not work at all. Typical manifestations of battery problems:
- dim headlights;
- slow windows;
- turning off air conditioner;
- weak response to the inclusion of the security mode;
- malfunctioning radio (turns off by itself when the volume is increased or the mode is switched).
The reason for this behavior may be poor contact at the battery terminals, the signs in this case will spontaneously appear and disappear. When the presence of such problems is observed constantly and in combination, then it is possible to judge the exact malfunction of the battery.
9. Service life
The average car battery lasts 5 years or less (3-4). The service life largely depends on the conditions of the car, the number of deep discharges, the frequency of recharging, the temperature of use and other factors. After 3 years of active driving, it is worth checking the battery for any internal or external problems. If there are no malfunctions, the battery can be used for some more time, but subject to annual diagnostics. If problems are found, the battery should be replaced.
Leading causes of battery death
The list of main reasons includes:
- Sulfation. Violation of the battery operation rules, long idle, incomplete or irregular charging, low level of conductive liquid in banks are the reasons why crystalline lead sulfate begins to form on the lattice plates. This process is called sulfation. The presence of lead sulfate interferes with chemical reactions inside the battery, provoking its deterioration.
- Regular short circuits. Micro circuits contribute to the shedding of the active substance from the surface of the plates into the electrolyte. Because of this, the conductive liquid begins to heat up, which leads to a decrease in its density. Signs of a closed battery may not appear immediately, but with the accumulation of a negative effect, other symptoms of a dead battery will appear: dark color of the electrolyte, clicks of the starter relay, problems with the auxiliary systems of the machine.
- Terminal oxidation. During driving, the electrolyte may leak or evaporate, leaving traces of oxides at the points of contact. Timely cleaning of the terminals will not allow the battery to sit down, otherwise the battery will quickly be discharged and become unusable.
Other causes of battery damage: ingress of foreign substances into the electrolyte, interruption of the current transmission circuit, improper connection to the current rectifier, regular recharging.
What to do with a dead battery?
First of all, you need to find the source of the problem, make sure that the dead battery really fails. It is important to consider that difficulties with starting the engine may be associated with breakdowns of other components (wiring, starter, generator, fuel pump).
To save a discharged battery, you can use the method of deep discharge and full charge, as well as using polarity reversal. The second method involves changing the battery poles (plus to minus or vice versa). Many unpleasant signs will remain after the polarity of the battery cans is reversed, so sometimes it is more rational to replace the old device with a new one.
You can exchange the battery for a new one with a surcharge at specialized points of sale, but this is the most unprofitable way.