Hello, I did this project for myself. But I decided to share this creation with you, maybe you’ll like it) 
Specifications:

1. Laboratory module (the most important thing is that it fits into the case) power supply: ZK-5KX 

2. Lithium batteries. 6pcs. Look at the choice which ones are more suitable. Connection diagram S6. I used high current 3500. 

3. BMS board. Also absolutely any for your capacities and needs. 

4. Initially, the case did not have a charge indicator. I cut it after the fact according to the size of the module, so this is also to taste. 

5. Depending on how you connect the charging, through which connector, you will need connectors.

Ability to change Voltage 0.6-36V and 0-5A. Internal power bank for 15000 mAh.
If you need more detailed information, please ask)

Thanks for watching and criticizing)