[SOLVED] Horrible sound after battery replacement.

Hi everyone,

I bought a JBL Xtreme in Australia, after 4 months the battery broke. I contacted JBL when I was in Belgium but they refused warranty because I bought the speaker in a different country.

So I decided to fix it myself! (if you want to skip the processes go to part 2)

I followed this diagram:

When I tested it I got 3.5V on each battery, yet when I tested the voltage on the connector I got nothing. I tried it inside of the speaker but nothing happened probably because the BMS board got too hot.

The day after I measured the voltage on the battery again and suddenly got 7.2V! So I put it inside of the speaker and it worked!! So I charged the speaker completely and the final voltage when it automatically cut of was 8.3V

I played the speaker like this for 1 hour on low volume to see if the battery got hot but all was good, so i tried to reassemble the speaker and I saw it wouldn't fit. So I trimmed a bit of the plastic of and realized it was the battery's circuit board that was too big.

So I moved the BMS board to the inside of the speaker and put some foam around the batteries so they wouldn't vibrate or get damaged when falling.

Then I put electrical tape around the circuit board and hot glued it to the side. I re-assembled the speaker completely and let the BMS board cool down all night. The morning after the speaker still didn't do anything so I briefly connected it to power and it worked again.

Then I went outside to test the speaker loud and I could immediately hear something was wrong I heard some vibration like there's something loose inside or the woofer is broken. When I came home I opened up the speaker and checked everything but there's nothing loose and neither the battery or the circuit board touch anything they shouldn't touch. I also re-checked the voltage on the battery and it was at 7.5v I don't know when exactly this started because the first time I didn't play the speaker loud.

So what did go wrong? Is it just the 18650 batteries that give too much power which made the woofers blow or is it some other component? Or did I do something else wrong?

Here are 2 examples of the sound:

It seemed the problem was air escaping from a hole in the front, I used some of the black gum inside the speaker to re-seal it. I also sealed the hole where the battery's cable comes out of. I also moved the BMS board back into the battery compartment and screwed it very tight.

It's crazy how a bit of air escaping could make the speaker sound so horrible! Although on some tracks it still doesn't sound right but I don't have another JBL Xtreme to compair it too, so maybe it's just me :P

Greetings

Dennis