Your motorcycle s charging system check is complete.
Motorcycle battery voltage when running.
The starter should be running at normal speed.
Your battery may even be holding a charge but it s the cold cranking amps that may determine if your battery needs replacement.
This is a huge part of your charging system.
Now push the starter button and watch what the voltage drops to.
With the ignition on and the bike not running switch on the lights and you should see the voltage drop slowly as the lights use up the power in the battery.
You should see the voltage increase on your meter even further up to around to 14 4volts this will vary from bike to bike.
If your battery is charging perfectly but your motorcycle still seems to keep killing the battery.
Your charging system is putting out the necessary voltage to the battery during a running condition past idle.
With the battery fully charged and functional it s time to test for battery voltage drop.
The alternator is fitted with a regulator that charges the battery while you ride.
With the multimeter on the same settings as above.
A low or failing battery can cause crazy readings during your testing.
A healthy 12 volt motorcycle battery should maintain a range from 9 5 10 5 volts under the load for a good 30 seconds straight.
Then measure the voltage from tab to tab just like before.
Or you may find it s not the battery at all and a charging system problem instead.
Hook up your dvom in the same manner you did for the standing voltage test and have an assistant thumb the starter.
Be in the know on whether you actually need a new motorcycle battery or not.
No need to go running to a dealership to spend money.
It doesn t matter if the bike starts or not what you re looking for is a voltage reading.
Perform a current draw test.
Now switch your multimeter to read ac voltage.
The relationship between your motorcycle battery and engine functions much in the same way as a car battery.
What you are looking for is that all three of the numbers are similar.
A good battery should not drop below 9 6 volts over 10 seconds or so.
If so this is good.
To check for voltage the motorcycle must be running and should be at about 2000 rpm.
Replace the voltage regulator if the reading is higher or lower than the 13 5 to 14 5 volt range to prevent insufficient or excessive charging.
Replacing the rectifier which converts the alternating current ac from your motorcycle s stator alternator to direct current dc before recharging the battery is also recommended at this time.
However it s important to note that normal riding may not be enough to fully charge the battery after being completely depleted.
This needs to be correctly charged and tested before you start and troubleshooting.
The actual number of the voltage is not terribly important.
