Need Help Building Portable Supply for Onewheel XR

Looking for help building a quality rechargeable portable power supply with 18650s in battery case for Onewheel XR. Hardware: 4210. Firmware: Gemini -4144.

Thanks!

What voltage is the battery of the onewheel xr? How many watt hour is the battery? From what I saw on the onewheel website 12v charger takes 75 minutes to fully charge one. 12v x 10A x 1.25 = 150WH
How portable do you want the power supply?
if you used the highest mAh cells 3500 mAh 7s5p would give you 453 wh giving you 3 + charges

I have a 7s10p battery pack and it weighs around 7 lbs 3.15 kg. It would charge the battery aprox 4 times

7s 18650 matches a 24v LA closer than a 3s/4s 18650 matches 12v La and there are lots of buck converters for 24v to 12v.
Later floyd