Battery compartment AA/AAA and SD-Card

This is a battery compartment which can hold up to four AA and AAA batteries and a SD card.
Unfortunately the lid does not fit very well when printed on a Replicator2x. The walls of the lid are not thick enough. I was not able to simply increase wall thickness in AutoCAD. Advice on how to do it is very welcome.
This model is a result of an assignment trying to satisfy the following requirements:
- Hold either 4 AA or 4 AAA batteries
- Hold a SD card
- Can be attached to belt or camera bag
- Protect batteries against splash water