T-Echo Rear Cover Flush - Supports 10mm Battery

A rear cover for the LILYGO T-Echo that can fit a 103450 2000mAh LiPo (Taobao link), without increasing the overall size of the T-Echo.

The stock rear cover has two brass threaded inserts for screwing on clips or accessories, that crush into a 10mm thick battery. This design removes the accessory mount in favor of fitting a 10mm thick battery, and is 1.2mm thinner on the inside.

Prints without supports. Ensure sufficient cooling for the screw posts or they may print poorly.

You may wish to set top+bottom layers to a total of 10, or use 100% infill, just to eliminate the ~1 layer of infill.

Updates:

* 2024-06-13: Reduce the battery space to just where the battery sits, to strengthen the back cover. Add 0.2mm more space for the battery. Add chamfers to screw holes so they will print better without supports. Tighten rounded corners.