Sorry this took so long. Here's the video explaining how I did the wiring to add the second (the old) set of batteries to your Ecosmart Scooter. This could probably be done on any 36v scooter.

Here is my Amazon affiliate link if you want to use the same switch that I used: https://amzn.to/3RyMEKp

I do get a small commission for sales but this is a very inexpensive switch. This will not make me rich. lol. It does help keep the channel going though.

Disclaimer: This is a video of me simply showing how I personally modified my scooter and is not to be construed as mechanical or electrical advice. I will not be held liable if you burn up your scooter or damage something :)