I'm looking for info on making modular containers or expandable containers but can't find any info, can somebody point me in the right direction?
It's pretty simple. Place a Container Controller. This is what you use to access the cargo. This has 8k of storage volume. Place a Container Extender directly touching this controller. And then you can keep placing more container extenders either directly touching the controller, or touching any other extender. Each extender adds another 8k to the volume of the controller, up to 320k. Container Controllers or Container Extenders from different controllers cannot be directly touching each other.
so if my maths are right this means you can Have 1 Controller and 39 Extenders connected together????
Yes, that is correct as long as you are referring to Bases and CVs. For HV's and SV's its a different Story as the max amount of Volume is 32k but as they are smaller you need a lot more of them.
Correct. A total of forty cubes. You CAN add more for redundancy, so if you take some damage you don't lose stuff. 40 cubes makes for a fast 8 by 5, single layer. Unfortunately, it is far from a perfect cube, so designing it efficiently into a ship is a bit more problematic. If you want to get to an efficient (volume-wise) solution for cargo, you can sort of combine the bulk storage and the heavy cargo boxes, which are two each. Add in 7 cargo boxes and you can get to a perfect cube of 64 blocks. This works very well for a cargo bay situation. Imagine a room two high. 4x4x4 means you can use the upper and lower layer as part of the floor and ceiling. This leaves room for a cargo controller box and 7 containers (ceiling) BBBB CBBB (floor) C= container controller, B equals box. Then an intervening layer in between, say of steel to compartmentalize. (ceiling) BBBBSBBBBSBBBBS CBBBSCBBBSCBBBS (floor) That gets you a mix of small boxes for things that dont' take up a huge volume, but needs slots (guns, boosters armor), and has volume for bulky things.
