Originally Posted by Doc_Wui

This is when I plug in my other charger and it usually works. Chargers do fail.

Lacking a spare, put a voltmeter on the charge output. For a 48V battery, it will be 54.6V, For a 36V battery, it will be 42.0V.

Then put the meter on the battery output. Again, a 36V battery is normally between 30-42V. A 48V battery is 40-54.6V. If you read less, it's a battery issue.

Usually on these bikes, the battery got old and wore out, They sell spares for Jetsons. Might be better to loan her a regular bike if you have a spare. Jetsons only have a short range. If it;s less than 6 miles, she could ride a regular bike.