- checking the electrolyte level in batteries;
- measurement of electrolyte density in batteries;
- electromotive force measurement (EMF) AB;
- battery voltage measurement.
Checking the electrolyte level in batteries
As already mentioned, AB is maintenance-free. It is filled with sulfuric acid, which is diluted with distilled water. Part of the water may evaporate, so check the electrolyte level from time to time and top up with distilled water if necessary, as insufficient electrolyte will reduce battery life.
To check the electrolyte level, remove the battery filler plugs. Lower a glass tube with an inner diameter of 3-5 mm into the battery filler hole until it stops in the safety net, pinch the top hole of the tube with your finger and carefully remove it from the battery. The height of the electrolyte column remaining in the lower part of the tube should be within 10-15 mm. At the same time, pay attention to the color of the electrolyte. The brown or brown color of the electrolyte indicates that the active mass of the positive plates has crumbled.
In addition, marks are applied on the translucent AB case «max» and «Min». The electrolyte level is considered normal if it is between these marks.
If the electrolyte level is below normal, distilled water must be added to the battery. Add water with the engine off, when the battery is cold.
Note. It is impossible to add tap water to the batteries, as it contains salts and organic substances that cause rapid destruction of the plates and accelerated self-discharge of the batteries.
Attention! If the electrolyte level in the battery is higher than normal, then the electrolyte in the battery may boil.
Electrolyte density measurement
The density of the electrolyte is used to judge the degree of charge of the battery. The lower the density, the more the battery is discharged. The density of the electrolyte can be measured using a hydrometer or density meter. Lower the hydrometer tube into the battery, and use a rubber bulb to draw electrolyte into it until the float floats. The division to which the float will be immersed will show the density of the electrolyte.
Measuring the density of AB electrolyte using a density meter is more convenient, since there are no glass parts in it - the body with a tube and seven floats are made of plastic, and, secondly, it is easier to use. The numbers printed on the body, opposite each float, indicate the lowest density at which it floats. Float indicating density 1.27 g/cm3, painted in yellow or red. The density of the electrolyte is determined by the floating float with the largest number.
If the electrolyte level is low, then first add distilled water to the battery and only after one and a half to two hours, when the water mixes with the electrolyte, start measuring the density.
With the obtained value equal to 1.28 g/cm3, battery is fully charged; at a value of 1.12 g/cm3 - completely depleted.
Attention! The density of the electrolyte depends to a large extent on its temperature, therefore the measurement results should always be brought to a temperature of +25°C.
AB charging
The battery can be recharged from any DC source with a voltage exceeding its rated voltage. There are two main ways to charge batteries: with constant current and with constant voltage.
The first way is better (in terms of depth and completeness of charge), but it requires a long time and constant monitoring of the charging process. The second method, although it does not provide a full charge of the battery, but allows you to keep it in working condition.
When charging the battery, it is advisable to use a charger that provides battery charging using the constant current method.
Before charging the battery, do the following:
- remove the battery from the car or disconnect it from the on-board network;
- unscrew the filler plugs from the batteries and simply put them on the filler holes;
- put newspapers or something similar around the battery, as the electrolyte will almost certainly spill during charging;
- Ensure that the area is well ventilated if charging is carried out indoors.
Charge the battery in the following order:
- connect the AB leads to the corresponding terminals of the charger;
- turn on the charger and set the charging current equal to 10% of the battery capacity;
- during battery charging, periodically check the current strength, electrolyte temperature, electrolyte density;
Note. If the temperature of the electrolyte exceeds +40°C, then stop charging, let the electrolyte cool down to +27°C and reconnect the battery for charging.
Warning! To avoid an explosion of gases released during the charging process, you must not bring an open flame to the battery and you cannot use a probe to measure the voltage of the battery.
The battery is considered fully charged if the density of the electrolyte and the battery voltage are constant for 2 hours, and when charging occurs, rapid gas evolution occurs («boiling» electrolyte);
- turn off the power supply of the charger from the mains;
- disconnect the wires of the charger from the AB terminals, tighten the filler plugs.
Attention! Do not turn off the charger, which is under load, by disconnecting the wires from the battery.
Note. Distilled water should be added to a highly discharged battery only after it has been charged, since during charging the electrolyte level rises greatly, which can lead to its leakage.
Removal and installation of AB
AB is located in the engine compartment of the engine and is attached to the tray with a clamping bar. Before removing the battery, make sure that you have the recorded radio code.
Attention! When the battery is removed, all fault codes recorded in the memory device of the ECU of the engine management system, as well as the readings of the electronic clock, are erased.
Before removing the battery, be sure to turn off the ignition and all current consumers.
Remove the AB in the following order:
- loosen the nut on the terminal «negative» wires and remove the terminal from the AB output;
- loosen the nut on the terminal «positive» wires and remove the terminal from the AB output;
Pic. 333. Mount AB: 1 - thrust bar; 2 - clamping plate flange AB; 3 - bolt, 20 Nm; 4 - battery holder
- remove bolt 3 (pic. 333), which secures the clamping bar 2 at the bottom of the AB, and remove it;
- remove the battery from the car.
Before installing AB:
- check the condition of the battery terminals. Remove large white or greenish deposits with a cloth dampened with hot water;
- clean the AB leads and wire terminals with medium grit sandpaper to a metallic sheen;
- wash and dry the AB cover, its side walls and bottom. This will extend the life of the tray on which it is installed, and the adjacent metal parts;
- check electrolyte level.
Install the battery in the reverse order of removal, while:
- make sure that the battery is securely fixed on the tray, as its vibration causes damage to the lead plates;
- lubricate the battery terminals with special Bosh grease or Vaseline;
- first connect the terminal to the AB output «positive» wires and then «negative»;
- after connecting the wire terminals to the AB terminals, cover both with a protective film (PVK or VTV-1 lubricant, «Unisma», WD-40);
- enter the security code into the radio and set the time on the clock.
Starting the engine with a discharged battery «smoking»
Attention! Failure to follow the recommendations below may result in battery failure, burns to drivers, and damage to circuits and electrical equipment in both vehicles.
When starting the engine from an external source of energy, such as the battery of another car, consider the following features:
- use, if possible, special jumper cables for «smoking», designed for cars with electronic ignition;
- try to purchase auxiliary starter cables with copper wires inside, as aluminum wires with «lighting up» they get very hot, as a result, the insulation can melt and, when removing the wires, you can get burned badly;
- for a car with an engine capacity of up to 2.5 liters, the cross-section of the starting cable must be at least 16 mm2. The size of its section is indicated on the package;
- the starting cable must have powerful connecting clamps.
Start the engine with a discharged battery in the following order:
- adjust the car «donor» (from which will be made «smoking») close to the Sharan's hood so that you can connect an auxiliary starter cable to a discharged battery;
Attention! Eliminate the contact of car bodies due to the possibility of a short circuit.
AB of both cars must have the same voltage rating - 12 V and approximately the same capacity;
- check the electrolyte level in the discharged battery. If necessary, restore it by adding distilled water;
- check the correct connection of the battery to the vehicle's on-board network;
- do not disconnect the discharged battery from the vehicle's on-board network;
- both vehicles must be set with the parking brake, the manual transmission shifted to neutral and the automatic transmission shifted to park «R»;
- turn off the ignition;
- turn off all current consumers on the car;
- check the reliability of the clamps and the integrity of the insulation of the auxiliary starting cable;
- connect the starter cable in the following order:
- 1 - clamp «+» cable to a discharged battery;
- 2 - clamp «+» cable to a charged battery;
- 3 - clamp «–» cable to a charged battery;
- 4 - clamp «–» cable to «mass» car body;
Note. Before installing the jumper cable clamps, make sure that the clamps do not come into contact with each other and the clamp «+» starter cable with housing (body, engine) car.
- start the car engine «donor» and bring it to a steady idle;
- start the car engine with the battery discharged. When starting, the inclusion of the starter should not exceed 7 - 10 s;
- if the engine does not start immediately, then pause 30-40 seconds before each new attempt so that the starter can cool down;
- Bring the engine with the discharged battery to a steady idle. Turn on for 10-15 s all consumers of the car's electricity to maximum power;
- if the motor runs stably, disconnect the auxiliary starter cable in reverse order (those. 4, 3, 2 and 1).
There are other ways to start the engine with a discharged battery.
Engine starting «with a push» or when towing a car are the most famous ways to start the engine with a discharged battery. However, these methods will have to be abandoned if the engine does not start due to a faulty ignition system or if the battery is too discharged (when the ignition is on, the control lamps of the devices do not light up).
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