Car battery quality plays a significant role in how long the battery is able to provide enough cold cranking amps to start the vehicle. This ability is what is known as ‘holding a charge’. A higher quality battery will hold a full charge through much more of the battery’s usable lifetime than a lower quality battery. The only way to test the real quality of your used car battery is by checking the brand. Exide, Interstate and the major automakers all supply or use batteries of fairly high quality. A car battery’s ability to hold a charge and state of charge can be tested by using a battery tester, which measures how long the battery is able to maintain a minimum current and voltage output when put under a known load.
For more info, see Getting the Best Car Battery Prices