Recommended battery "ZMI 20000mAh PD battery" not working on LattePanda Delta

Hello, 

I have purchased the battery recommended on this page:
https://docs.lattepanda.com/content/delta_edition/powering/

This battery:
https://www.amazon.com/ZMI-Pixelbook-Ni ... 468&sr=8-1

I charged the battery all the way, plug it in to the USB-c port on the LattePanda and absolutely nothing happens . My Lattepanda Delta does work as I am able to plug it in using the provided PD adapter. Can someone let me know what I am doing wrong here?

Also, it is recommended to use a Lipo battery "JST 4p DC Input Connector". Can someone recommend a battery?

Thank you!!!