Controllers Turns Off Right After Connecting + Nuances

I have checked this forum far and wide but haven't found my answer nor does it describes my issues. My issue im getting is that after paring/connecting to my PC or iPhone via bluetooth with pulsing yellow light, it simultaneously shuts off like it lost power. Heck, my Linux PC thinks the battery is less than 5% remaining.

I have swapped out the battery with a new one and still getting the same problem. I have confirmed the battery are charged as both the old and new battery reads 4V on my voltmeter. When I hook it up to an wall charger however, it connects then stayed powered on.

I have also done the trivial troubleshooting such as holding the PS button and Select/Share button to re-pair (Bluetooth), also press & holding the Reset button for 10 seconds to wipe out the paired address but to no avail. I do not have a PS4 console if its somehow needed to access certain settings or tools

If the community are stumped then im fine with using this controller soley wired as that works correctly.

Edit: I should mention that I never seen the LED bar changed to other colors other than Yellow & Off.