Hacked a Kentli AA 2800 mill-amp battery for my MP3 player

[sam_sam_sam]

Here is the story of why I did this battery hack and this mod to my MP3 player

I got this MP3 about 10 years ago and when was brand new if you left the battery in it would be dead the next day so you had to remember to take the battery out of it
then put back in when you want to use it---> (this a pain in the a** if you what I mean

I even use the Kentli battery in it and would run this battery down to it might take a day or so to this (Really) I had with this MP3 player so I would hardly use it because of this

So a couple week ago I got a very bright idea to cut the metal case on this battery and
see if I get buck convetor out of it with out catching the battery on fire well the first attempt did not go so well when I cut the top off the battery I cut into the board and the top of battery got so warm that almost could not hold on to the battery

The battery was still ok but a little run down

A week later I tried this again and this I was able to get the board out in one piece

Here where the fun begins is soldier the small wire on this little board
I took a ten foot long USB cable and cut the small connector end off
and just used the red and black wires and cut off the white and green wires not need

Some more fun with mod the display on the MP3 has a back light that was not hook up but want to use so I took 2.2k ohm resistor and hook it up to the red wire on the USB cable now I have backlight now this is cool now I can see it the dark

Now to put MP3 back together this was real fun to get all the wires in my the right place so the switches would work it took a few tries before I got back together and everything works

The buck convertor board fits where the battery went all I had to is cut a small notch for the USB cable can come out the back of the player It works real good now

[sam_sam_sam]

Re: Hacked a Kentli AA 2800 mill-amp battery for my MP3 player

I have one very small problem with this setup it when it goes from one song to the next you hear small amount of ringing in the background what can I do to get rid of it it is not very loud but you can hear it

This is with the volume almost all the way up on MP3 player an on the Bluetooth speakers with the volume a little lower yes do not hear it at all

[sam_sam_sam]

Re: Hacked a Kentli AA 2800 mill-amp battery for my MP3 player

Update

I found the problem was this

The Bluetooth speakers that I was using has USB output port that I used to also power the MP3
Player is where I was getting the ringing noise from

As long as I power the MP3 player from a different USB power pack it is fine the ringing is not there