How to check your car battery?

SIMPLE METHODS to check your car battery:


Perform a visual inspection

  • If there is corrosion on the battery terminals, you should clean them with a wire brush and apply copper grease.



Check the electrolyte levels using the indicator


Remove any dust and dirt from the indicator and look at its colour:

  • Green means that the electrolyte level and charge are normal.

  • White means that the charge is weak and must be charged.

  • Red means that the acidity of the electrolyte has increased and that the water level has dropped.

  • Be sure to disconnect the battery terminals.

  • Add distilled water if needed.

  • Be sure to wear rubber gloves when working with electrolyte: if it comes in contact with your skin, it may cause chemical burns.




Check the electrolyte level using the special markings on the battery cover


Make sure that the electrolyte level is between the "min" and "max" markings.


  • Be sure to disconnect the battery terminals.

  • Add distilled water if needed.

  • Be sure to wear rubber gloves when working with electrolyte: if it comes in contact with your skin, it may cause chemical burns.


Check the electrolyte level using a glass tube if your battery has no markings indicating the level

  • Note: This only applies to serviceable batteries.

  • Check the electrolyte level in each cell.

  • Park the car on a level surface. Clean the battery cells of dust and dirt.

  • Remove the cell cap and insert the tube.

  • When the pipe reaches the plate, fill it and take it out.

  • Replace the cell cover.

  • The height of the electrolyte in the tube indicates its level in the battery.

  • Be sure to disconnect the battery terminals.

  • Add distilled water if needed.

  • Be sure to wear rubber gloves when working with electrolyte: if it comes in contact with your skin, it may cause chemical burns.




Check the density of the electrolyte

  • Park the car on a level surface. Clean the battery cells of dust and dirt.

  • Remove the cell cover and insert the hydrometer tube.

  • Pick up a complete electrolyte sample in the hydrometer. The hydrometer tube should flow freely in the liquid.

  • The reading where the electrolyte meets the scale of the hydrometer shows the density of the electrolyte.

  • Carefully drain the electrolyte back into the battery.

  • Replace the cell cover.

  • Be sure to disconnect the battery terminals.

  • Note: This only applies to serviceable batteries.

  • Check the electrolyte density in each cell.


Measure the battery voltage using a voltmeter or multimeter


Change the position of the multimeter to DC measurement and set the interval to 20 volts.

Connect the multimeter's black probe to the negative battery terminal and the red probe to the positive terminal. View the reading on the multimeter screen.

  • If the battery is fully charged, the voltage should exceed 12.6 volts. A voltage of less than 12.6 volts means that the battery is less than 50% charged.

  • If the battery voltage is less than 11.6 volts, it means that the battery is completely discharged.

  • Be sure to disconnect the battery terminals.

  • Clean the terminals with a wire brush before checking them, if necessary.




Check the battery charge level using a battery tester

  • Be sure to disconnect the battery terminals.

  • Clean the terminals with a wire brush before checking them, if necessary.

  • The battery should not have been used for 6-8 hours before the check.

  • Only perform the check if the electrolyte level is normal.


Connect the probes to the positive and negative terminals of the battery:

  • Measure the battery voltage without load resistance.

  • The car battery is 100% charged if the readings are between 12.6 and 12.9.

  • The car battery is discharged if the readings show lower than 11.5.

  • Repeat the measurement a few times.

  • The check should not last longer than 6-10 seconds.

  • Wait 3-5 minutes between measurements.

  • Measure the battery voltage without load resistance.

  • The car battery is 100% charged if the readings show higher than 10.2.

  • The car battery is completely discharged if the readings show lower than 7.8.