Simulation car battery model

This is the power bank that powers the simulated engine。
The appearance is designed according to the shape of the car battery。
The shaping size is L105mm W70mm H75mm，With power display and switch function，And the built-in battery can be charged through the booster plate。
Built-in batteryI used a lithium battery from the remote control model 3S4000maH，It is also possible to use the 18650 battery according to individual circumstances，The working video works with the engine I printed， and of course the 12V output can be applied to other scenarios as well。
Interested friends can see the video link：
https://www.bilibili.com/video/BV1Su4y1p7kC/?share_source=copy_web&vd_source=5c38b5f4f8fac13817da6ad46b2c8f6a