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Modal bluetooth wireless headphones. They will turn on while they are charging, but they will immediately turn off when disconnected.

Hi, The battery is not holding its charge and needs to be replaced. Even rechargeable batteries have a life span. Unfortunately, according to the user guide it has non user replaceable rechargeable battery. If you wish to try and replace the battery, you will have to work out how to open the headphones to find the battery, as there is no information online that I can find that shows how to do this. Once you have found the battery, there should be product information printed on it which should help you in finding a suitable replacement.