How to Load Test a Motorcycle Batteryby Chris Gilliland
Testing a motorcycle battery with a voltmeter is a fairly easy task that will provide a basic picture of the battery's health. This static testing method can only tell you so much. A load test, which places the battery under a real riding scenario by having power drawn from the motorcycle's lights and ignition systems, will give you an accurate reading of its condition. The procedure is not much more complicated than a static test, but the results could reduce problems down the road.
Access the motorcycle's battery, either by unbolting the seat with a socket wrench or by pulling the side cover off of the motorcycle's frame.
Leave the ignition switch in the "Off" position and set your multimeter to read a DC (Direct Current) voltage scale, using the setting dial on the voltmeter's face.
Connect the voltmeter's red probe to the battery's positive terminal and black probe on the negative terminal. Take note of the battery's static voltage indicated on the voltmeter. Charge the battery with an automatic battery charger if the voltage is below 12.1 volts DC.
Keep the voltmeter's probes in place on the battery's terminals. Turn the ignition switch to the "On" position and take note of the battery's voltage. Replace the battery if the voltage is less than 10 volts DC while under a load.
Remove the voltmeter's probes and turn off the ignition. Reinstall the seat or side cover onto the motorcycle.