18.9. Rechargeable battery

The rechargeable battery is a device for storage of energy in a chemical form which can be used further as electricity.

The rechargeable battery works thanks to the fact that two various metals, being in acid solution, create potential difference therefore electric current is developed.

  1. On cars unattended rechargeable batteries are installed.
  2. In the rechargeable battery it is not required to add the distilled water.
  3. The battery is completely tight except for small air vents in a cover.

Survey of the rechargeable battery


  1. Switch off ignition and all consumers of electric energy.
  2. Disconnect wires from plugs of the rechargeable battery. The negative wire needs to be disconnected first of all and to connect in the last turn.
  3. Remove the battery from the car.

If the case of the rechargeable battery is damaged, remove the battery in rubber gloves to protect skin from electrolyte.

  1. Check elements of fastening of the battery as they can be damaged by the electrolyte which got on them. If necessary clear them warm soda solution.
  1. The same solution clear the top part of the battery.
  2. Examine the battery on lack of cracks. If there are cracks, replace the battery.
  3. Clear plugs of the rechargeable battery.
  4. Clear internal a surface of clips of the wires connected to plugs of the rechargeable battery.
  5. Install the rechargeable battery in the car.
  6. . Connect wires to plugs of the rechargeable battery.
  7. Reliably delay fastening of clips of wires to plugs of the rechargeable battery.
  8. Apply a thin film of vaseline on plugs of the rechargeable battery.

At charging of rechargeable batteries explosive mix of gases is emitted.

During the work with wires and electric devices use of fire, the sparking devices opened by fire-dangerous light devices and smoking is forbidden. It is necessary to avoid emergence of sparking at the address with wires and electric devices.

Never close directly the battery plug – there is a big danger of getting injured because of strong sparking.

Testing of the rechargeable battery

Check of specific weight of electrolyte

Specific weight of accumulator electrolyte changes with a temperature. Temperature increase leads to reduction of specific weight and vice versa.

Specific weight of electrolyte of completely charged rechargeable battery has to be in limits between 1,260 and 1,280, at a temperature of 26,7 °C.

Adjustment of specific weight has to be carried out by addition of 0,04 points for each 5,56 °C higher than temperature of 26,7 °C or subtraction of 0,04 points for each 5,56 °C lower than temperature of 26,7 °C.

For example: Indications of the areometer – 1,280 at a temperature of 5.56 °C. According to a difference of temperatures it is necessary to modify specific weight on 0,028 points. True specific weight is equal to 1,252.


Do not measure the specific weight of electrolyte at once after a dolivka of the distilled water.

Distinction in the specific weight of electrolyte on 50 and more points between banks of the rechargeable battery indicates that the battery is faulty and it needs to be replaced.

Charging of the rechargeable battery

Specific weight
Charging method
Slow charging (5A)
Bystry charging (20A)
Less than 1,000
14 h
4 h
12 h
3 h
10 h
2,5 h
8 h
2,0 h
6 h
1,5 h
More than 1,220
4 h
1,0 h