Testing the battery

Check and testing is designed to tell us things we want to know about individual consumer cells and batteries to substantiate if the customer claims will be accepted or not.

1.    Visual control:

  1. Documentation check :Customer must have validated quarantee paper and a bill (from the store) for „Munja“ battery.
  2. Date of production and sell check:We quarantee that „Munja“ battery will work properly within 24 months from the date of its selling (which must be written on quarantee paper), but the date of production and the date of selling must be within 6 months. Customer must use the battery according to the instruction manual and with proper function of the electric installatins in the vehicle.
  3. Terminal check :Terminals must be clean without sulfate layers or mechanical damages. There must be no grease layer between terminal and battery pole. In the case of customer claim, terminals and the battery poles must be clean – sulfates or grease between decrease the contact and can lead to difficulties with engine start.
  4. Electrolyte level check  :Electrodes must be covered with an electrolyte for about 15 – 20 mm. Electrolyte in all cells must be of the uniform density and level. If electrodes are not covered with electrolyte, that part of it has no function anymore. It influence the battery capacity, battery does not have adequate power (that is designated on the sticker on the battery).IMPORTANT: In the case of the electrolyte loss, you can add just water (destiled)
  5. Mechanical damage check:In the case of mechanical damage (container, cover, battery poles), we do not accept the customer claim.


  1. With voltmeter we test the voltage of the battery, and with areometer we check the electrolyte density.
    • Battery is fully charged at the voltage 12,50 V and higher.
    • Electrolyte densities are at the bottom of the page.
    • If the battery voltage is lower than 12,50 V, it is discharged and must be recharged.
    • If the voltage is about 10 V, probably it is a short circuit, and electrolyte densitiy in every cell should be checked. If it is uniform in all cells, battery should be recharged and then tested. In the case that densities in some cells a lower, it is probably short circuit in that cell, and heavy duty test should be performed. Only recharged battery can be tested.
    • Customer claim must be accepted in the case of the battery short circuit.
    • Batteries with voltage under 10 V are in deep discharge state, must be recharged and heavy duty tested. If the battery is still discharged, customer claim can not be accepted because of non adequate maintenance of the battery.
    • If the battery has adequate voltage and electrolyte density in stand by conditions, but on duty voltage is lower thab 9,98 V, customer claim should be accepted because of the short circuit.
  2. Hermeticaly sealed container testingCustomer claim should be accepted in the case of the electrolyte leek between container and its cover without mechanical damage.
  3. Electrical installations in the vehicle check:At the medium revolutions per minute (rpm) of the engine, voltage on the electrical instalations should be within 13,8 – 14,6 V. In other cases, customer claim should not be accepted, because the battery was not operating in the adequate mode.


Electrolyte density on temperature dependence:

0 C 5 C 10 C 15 C 20 C 25 C 30 C 35 C 40 C
Electrolyte density(g/cm ) 1,295 1,29 1,287 1,284 1,28 1,276 1,272 1,27 1,265


Charge current value is 10% og battery rated capacity. Time of charging is not regulated, but we can accept that battery is fully charged if the electrolyte densitiy has not been changed in last 2 – 3 hours during charging process.

Date of production and sell check