Battery load test
A battery load test determines how well the battery performs under load. The test determines the battery’s ability to deliver starting current and maintain sufficient voltage to operate other systems. In other words, if the battery can sustain a high discharge for some time and the voltage is still relatively high, then you know the battery has good capacity and is in good condition. If the voltage drops quite quickly, the battery capacity is low.
The battery load tester serves to carry out the load test. It contains an ammeter, a voltmeter, and a high power variable resistor. Depending on the strength of the battery, the amount of load for testing is determined. The tester draws current from the battery through the resistor. An ammeter measures the amount of current drawn. The maximum draw current and battery voltage drop define the battery state.
There are several prerequisites for the battery test. The battery electrolyte should be at room temperature, between 21°C and 27°C. A cold battery shows a significantly lower capacity. Never test a sealed battery if its temperature is below 15°C. A load test is performed only on a fully charged battery.