Editing Load testing (section)

==Car charging system==

A load test can be used to evaluate the health of a car's [[Battery (electricity)|battery]]. The tester consists of a large resistor that has a resistance similar to a car's [[starter motor]] and a meter to read the battery's output voltage both in the unloaded and loaded state. When the tester is used, the battery's open circuit voltage is checked first. If the open circuit voltage is below spec (12.6 volts for a fully charged battery), the battery is charged first. After reading the battery's open circuit voltage, the load is applied. When applied, it draws approximately the same current the car's starter motor would draw during cranking. Based on the specified [[cold cranking ampere]]s of the battery, if the voltage under load falls below a certain point, the battery is bad. Load tests are also used on running cars to check the output of the car's [[alternator]].