The manual states that the red light will turn off when it is fully charged, this is the way our original prototype functioned and we made the instruction manual based off the prototype. However, when we did our main production run of the product, this was not programed into the charging function.
We have had several customers contact us about the red light not turning off. Even though the red light does not turn off, it will be fully charged after about 4-5 hours. Unless there are other issues with your speaker, it should be totally fine.