RC Bump Starter Box Restoration Upgrade Test

I got this bump box in my RC ebay lot. I would like to start using this in the future because the electric start and pull string rob so much power. Too parasitic draw.

Voltmeter on the box
https://www.amazon.com/gp/product/B07GQMN88W/ref=as_li_tl?ie=UTF8&tag=fintechcomm0f-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B07GQMN88W&linkId=bbb931ce0c8ec60ac9861af7a78e7da6

Zee Lithium Batteries 5200mah
https://www.amazon.com/gp/product/B07M7C7WN8/ref=as_li_tl?ie=UTF8&tag=fintechcomm0f-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B07M7C7WN8&linkId=9242a7230e9eafa3f9faa281daf73d43