Avigo Extreme Scooter
The model # 8801-01 is for the Avigo Extreme electric scooter, so that is definitely the make and model of scooter that you have.
The battery is located directly under the plastic footplate which is attached to the scooter's metal frame with screws. The heads of these screws are accessible from the top side of the plastic footplate. To detach the footplate all of the screws need to be removed and then the footplate can be lifted up off of the scooter and the battery will then be visible underneath it.
To install a new battery with attached wiring harness and connector, simply plug it into the scooter where the old battery was unplugged, and then place the plastic footplate over the scooter's frame and reinstall the screws that hold the footplate to the scooter's frame.
Here is a link to the page that we sell Avigo Extreme scooter parts on: http://www.electricscooterparts.com/avigoextremeelectricscooterparts.html
Please let me know if you have any questions.
Here is a link to the Avigo Extreme battery charger: https://cart.electricscooterparts.com/ProductDetails.asp?ProductCode=CHR-12V1ACX
Please let me know if you have any questions. Thank you.