It’s probably time for a new cable. If you recall, my brand new barely moved Fitbit charging cable died from what I would consider no use, and the first things that were indicative of this were slow charging.
You can try cleaning the contacts with alcohol, switching to a different USB charger, and when that doesn’t work you can contact Fitbit (which I did, and received a warranty replacement after many hoops,) or purchase a third party charge cable replacement.
There are many reasons I sold my Fitbit, this was one. Customer service asking me to install Flash was another. Massive caloric miscounts, thousands of fake steps a day. I could go on.
I did not expect that those around me would be experiencing the same issues I had with a garbage cable that came straight from the factory, but here we are today with the second one this month being complained about at my office.
My first thought these days is that it’s a bad cable. I mean, try everything else before you buy anything, but it’s a bad cable.