How to choose a car battery?

How to choose a car battery?
Advice from Vilnius Gediminas Technical University expert

It is not surprising that winter is the time of the year when the number of problems associated with car batteries becomes the highest. How to find the best solution in case it is necessary to replace the battery? How not to get confused among brands and not to end up paying for a well-known name but getting a low quality product? Scientists from the Vilnius Gediminas Technical University’s (VGTU) Motor Vehicle department will help to find answers to these questions

Docent Alfredas Rimkus explains which parameters can help distinguish "good" battery from "bad", by comparing several different car batteries in the VGTU laboratory. Comparative results of the study were surprising: there is no significant difference between the batteries of different brands.


“When choosing a new battery you should measure its voltage (it should not be not lower than 12.5V) and the starting current as well as, if possible, the electrolyte level above the plates and the density of the electrolyte. It is required to be 1.28 g/cm3, however, in most cases it is impossible to check it since the modern battery market consists predominantly of batteries that are completely sealed, with their sections filled with electrolyte at the factory. Although it is not difficult to measure the battery capacity, it requires special equipment, therefore only experts can do it. All other motorists will have to rely on manufacturers’ professionalism and honesty of sellers.” admits A. Rimkus.


After checking four different batteries’ parameters ("AD", "Bosch", "Exide" and "Varta") in the laboratory it was revealed that all of them with a very slight error meet their specifications. The differences between starting currents and capacity parameters that were indicated were likely to happen owing to unequal charge levels and storage conditions of the batteries. However, all batteries were ready to work.


"AD Baltic" product manager stresses that if the alternator is working correctly and a quality new battery was properly selected and installed in a car, the battery will reach the starting current declared by the manufacturer even if at the beginning lower amperage was recorded. However the alternator will not fully charge the battery with a capacity that exceeds the one required by the car manufacturer. In this case, the battery should be checked and charged additionally every couple of months (especially during the cold time of the year).


Both VGTU scientists and automotive business professionals note that factory defects are often found within 2-3 months of use. If the battery "dies" after six months, in most occasions it is due to misuse or electrical system malfunction, such as ineffective work of the alternator or current leakage. Objective reasons for short battery life – its age or the quantity of launch cycles make up only 10% of cases that make us look for a new battery. Up to 90% of faults are caused by car drivers themselves.