YES it was typo everyone makes mistakes

And since i know so much about batteries since work at a company that uses batteries and i run tests

RICH is correct on the official rating of the battery

BUT since the board is adjustable can set at 3.6 volts or 3.8 volts.

The old saying goes "better to be safe then sorry" so at 4 volt it may or may not hurt it

@Technopro, did the answers provided solve this question? If so don't forget to close the topic. I'm sure @PJ would appreciate it (unless you believe someone else deserves the credit)

Yes thanks everyone. This helped me understand a whole lot. I've come to the conclusion to just modify the board to move the charging port and make it possible to turn the speaker on and off and charge the same way it is right now. Later on I may go back to this and attempt it.

Everyone helped me out, and I thank everyone for that, but rich's responses answered the questions I had in the best understandable way. Thanks!