Every day we start the car and do not even think about how this happens. In order for the engine to begin its work, a whole range of systems and mechanisms is used. One of the most important in this chain is the battery. Without it, it is impossible to start the motor. Over the years, the battery loses its capacity. The car starts to start worse. Also, often the owners have a problem of lack of charge. Why does the battery not hold a charge? Find out in our article today.
When to sound the alarm?
At what voltage can I say that the battery does not hold a charge? The minimum value for starting the motor is 12.5 volts.
In this case, the motor will resume operation at the first turn of the key. If this figure is less than 0.5 volts, the motor will start, too, but with great difficulty. A voltage of 11 volts or less is considered critical. In this case, there is a risk that the engine will not start at all. How much charge does the battery hold? Ideally, it should maintain a stable value without recharging up to three years (but subject to regular use of the car, as it charges the battery generator). If, after arriving home in the evening, the battery has run out the next morning, it means that the battery is faulty. In the event of downtime, it must be kept for at least one month.
Common reasons
You need to start looking for a problem with a small one. Visually inspect the contacts that go to the battery. Terminals must not be oxidized. If they are available, it is difficult to start the engine both on hot and on cold. The reason is simple - the terminals are loose on the battery terminals. Accordingly, a lower starting current goes to the starter.
And after starting the battery can not fully charge from the generator due to the same oxidation. As a result, the battery does not hold a charge well, and the car is difficult to start. Another commonplace is damaged fuses on the generator. They are metal and are in a separate block. If these plates burn out, the battery will not charge. As a result, all electrical appliances will take energy from the battery, but it will not be replenished. The solution is to replace the fuse.
Banks
This is a more serious reason. Banks are the very six holes that are in the battery. Each jar contains lead plates. The latter are placed in an acid electrolyte. In the process of contact between the plates and the electrolyte, electricity is accumulated, which is then used to start and operate the car. The voltage in each jar is approximately 2 volts. And if one of the cans does not work, the battery will only charge up to 10 volts.
These elements become unusable for two reasons. It:
- Electrolyte Evaporation How to determine this? When loosening the cap, you may notice a low level of fluid. In a certain bank, it will be less than in the rest. But it also happens that liquid evaporates in several compartments at once.
- Shedding plate. In such a situation, the electrolyte level may be normal. But the liquid itself is not transparent, but black (almost black) in color.
And if in the first case the problem can still be solved by adding distilled water, then with the deformation of the plates the only way out is to buy a new battery. Note that the battery capacity will not drop after adding distilled water. In banks, it is she who evaporates, not acid. The latter is much heavier and stays on the plates.
Plate closure
Improper operation can cause this phenomenon. This happens if the battery often runs down to zero. There may still be freezing of the electrolyte. But this happens if the car often stands in the cold over 30 degrees. To prevent plate freezing, in severe frosts, it is recommended to keep the battery warm, that is, bring it with you to the house.
Battery does not hold charge: plate recovery
Some are trying to restore such a battery by prolonged charging with low current strength. But it will not do anything. This battery is restored as follows. First, rinse the cans with distilled water. She fills the compartment to the maximum. Then they mix (in this case it is possible and even necessary to turn the battery upside down) and drain. If necessary, repeat the procedure again until clean water flows out of the holes, without dirt and a dark shade. In some cases, it is thus possible to clean the plates from oxidized particles and restore the old battery to life. But if there is too much dirt, such plates may no longer take charge even after 10 washing cycles.
Desulfation
If the battery does not hold a charge, salts may have deposited on the plates. They need to be deleted. To do this, in the store we purchase a special desulfatizing additive to the electrolyte.
Also, the removal of salts can be done using a special memory. The desulfation procedure is carried out in several steps:
- First, the purchased additive is dissolved in fresh electrolyte (its density should be at least 1.28 grams per cubic centimeter). It takes a lot of time - 48 hours.
- Next, electrolyte is poured into the banks. You should check its density. This is done using a hydrometer. This parameter should be at least 1.28 grams.
- After that, plastic plugs in banks are twisted and a charger is connected to the battery. In order for the battery to hold the charge for a long time again, several charge-discharge cycles must be performed. On the memory, you need to set the minimum current strength. It should be no more than one tenth of the maximum. When the voltage on the battery reaches 13.8 volts, you should reduce the charge current by half. Next, we measure density with a hydrometer. Leave the battery for two hours. Then we take measurements again. If the density does not fall, then we were able to restore the dead battery.
But that is not all. We need to make an electrolyte adjustment. To do this, bring it to a density of 1.28, and then add distilled water. After that, the battery is discharged. A powerful lamp or resistor is connected to it and the current is limited to one ampere. You need to wait until the voltage drops to 10.2 volts. From the moment the load is connected, you must enable the timer. This is an important parameter during battery recovery.
The discharge time must be multiplied by the discharge current. So we get the battery capacity. If it is below the nominal, you will have to repeat the charge-discharge cycle. And so on until the capacity matches the factory one.