Editing Fallout 4 mods/Stash Those Caps (section)

===THE CATCH - VERY IMPORTANT===
Warning: DO NOT ATTEMPT TO TRANSFER MORE THAN 65,535 CAPS AT ONCE.  YOU WILL LOSE CAPS.

Part of the joy and frustration of doing these kind of mods is bumping up against bugs in the game itself.  Some, you can get around.  Others you can fix yourself.  And others you most likely have to live with, at least for now.

Integers are stored internally as 32-bit values.  However, the AddItem() and RemoveItem() functions only process item count numbers as 16-bit values.  That means that while an unsigned integer variable can hold values of up to over 4 billion, you can ever only add or remove items from inventory or containers in increments up to 65,535.  This is made worse by the fact that the FO4 container/item transfer UI slider is high-limited at the total amount of items (which can go up to 4 billion), but NOT the total amount that can be TRANSFERRED AT ONCE (65,535).  If you attempt to transfer more than 65,535 at a time, the number rolls back over to zero. 

You can test this for yourself.  Go into console and type: "player.additem 00059af8 100000" and see what happens.  You won't get 100,000 pencils.

This is a Bethesda bug.  They clearly never expected anyone to attempt high count transfers like this.  It may be why they opted to not make caps transferable in the first place (I'm guessing to simplify their console ports).  Until a) AddItem() and RemoveItem() can handle 32-bit integers, b) the UI slider is fixed to cap the maximum, or c) the F4SE guys give us a better alternative to any of the above, there's likely nothing I can do about it.

You can carry as many as you like, and store as many as you like in a single container.  You just can't transfer them in larger increments than the functions can handle.  Again, blame Bethesda.  Any complaints about this issue (unless you have a clever idea for fixing it) will be roundly ignored.