Everyone owning a XBOX360 with wireless controllers came across a phenomenon where older controllers were switching off randomly while playing or if they were moved too quickly. Me and everyone i know always blamed the battery contact springs being too short and everything the controller switched off it was completely normal to remove the battery pack and pull on the springs so that they would be a little longer and would press more tightly on the batterie contacts.
A few years have passed and my Xbox was sitting unused in some storage box. Until yesterday where a friend and me decided to play some good old Halo 3. We put new batteries in the controllers and noticed that they struggled to stay on for even a few seconds. After playing a few hours with my benchtop power supply soldered to the controllers contacts I've started to investigate further into this issue and took the controller apparat:
Not to my surprise I've quickly found that the contact springs weren't the culprits all along. What causing the switch offs was a contact in the battery pack itself, that only closes the connection between the batteries if the pack is inserted into the controller. This is done with a little notch on the controllers back, that pushes the two metal pieces that connect the two batteries and closes the circuit.
Over time these metal pieces corroded quiet a bit and the springs of the battery packs loosened up which resulted in really bad to nearly nonexistent contact between the two batteries.
Now my question is: Why all of this? This seems like a point of failure that could have been easily avoided. The only thing I could imagine is to avoid short circuits if a battery pack is thrown into a bag. Because of the missing connection a short circuit would be nearly impossible. But then I wonder who would use a battery pack in a way like this as it's just a fancy AA cell holder. So why not just take some extra batteries with you as swapping them out takes only a few seconds longer than switching to a pre-equipped battery pack? I don't even know if the battery packs were purchasable without a controller as I can see no use in having more battery packs than controllers.
Am I missing something? Or am I in inherent danger due to the bridge I've soldered between the contacts? (Just kidding)
Edit: I've just looked it up. There are a lot of aftermarket "battery holders" available. I guess mainly because of the above mentioned issue. I don't know if Microsoft ever sold original batterypacks.