Summary

Thanks to PhilT4 for the great design and Seibar for the Remix.

This is a light version of the 1 battery, which can cut off 20% print time, but the battery only slide in one way

for 1 battery https://makerworld.com/en/models/194823
for 2 batteries https://makerworld.com/en/models/191665
for 3 batteries https://makerworld.com/en/models/191662
for 4 batteries https://makerworld.com/en/models/147540