Small Engine Troubleshooting Problems? Ask a Mechanic Now.
If you hook up charger , does it show to charge? With battery gage showing only one bar, it is seeing low voltage, either a bad connection or wire, which feeds the meter. Do you have a voltmeter to check the unit? Are the batteries connected properly? 12 volt scooter, or 24 volt ? If 24 volts, batteries have to be posiitve to negative. !2 volt, negative to negative, positive to positive.
What does the voltmeter show voltage is at the battery gage? If less than battery voltage, trace back to find voltage loss between meter and battery pack.