Rechargeable battery retrofit for microphone stand

[xyzzy]

I got one of the inexpensive rotating microphone stands from alix, the kind with an analog output.  My computer soundcard is better than the cheap cmedia chip in the usb type.  But I was annoyed at the rate it ate 9V batteries.

Two AA sized lithium rechargeable will just barely fit inside the 9V holder.  They provide enough voltage for the amplifier board to work and should last 50+ hours before needing to recharge.  I added a protection board to the batteries.  Otherwise leaving the microphone on and draining them completely could kill the batteries.  It also limits to the current to a safe level.  

Then there was space for a lithium charger board above the cells.

The charger board, despite having a USB-C connect, didn't work with a normal USB-C phone charger.  For some reason it failed to include the resistors needed to enable a USB-C charger to detect a connected device.  But I was able to modify the board to work, by adding the two very tiny resistors visible by the "R" in RCS near the USB-C connector.

A melted hole in the lid shows the charge status LEDs.

[spectre6000]

What are you using the microphone stand for? Also, where are you getting USB charging boards that are missing critical components?

[xyzzy]

It's for a timegrapher.  Plenty of threads on that here, also on microphone selection.  This one works pretty well.

Charging boards with components missing from their design?  Aliexpress of course.  Direct from the big rock candy mountain.  Where else does one buy electronics of dubious functionality?  Same place one can get out of alignment crystal press tools.