I don't work for Bose but you may want to say:
1. Is it a soundsport wired or a soundsport free
2. how old is it
I have a soundsport wired for a year or two now and am having to charging or usage issues as you describe. Early on, it was loosing power after fully charging and not being used. But a firmware upgrade seem to fix that. Now if I charge it to 100% and comes back days or a week later it is still at 100% (though that is not your 'problem').
I have been having an issue for a long time with my SoundSport Wireless headphones charging for hours, they say they are at 100%, then 20 minutes into my run it says they are dying and I need to charge them. Not real happy with what is supposed to be one of the best brands around. I've tried everything, resetting them, software updates, you name it. Nothing seems to help. Headphones that last me 20 minutes are of no use to me. Is there a fix in the works or can I get a new pair? I have the 2 year Geek Squad plan that covers them until April 2020, perhaps I should go that route?
I would suggest either contacting your local Bose support team to see what service options we can offer you, or possibly even follow up with your extended warranty/gadget protection plans.
Let me know if there is anything I can do. You can private message me if you have any further questions.
Brandon_C - Community Support