I have an HD7 2014 Fire which I use mainly as a tablet for streaming video. It sits on my desk and is always plugged into the charger. Up until last summer, I could stream all day long with it plugged in and still have the battery show as 100% when I turned it off. However, late in the summer, I started noticing the battery would drain, even though it was plugged in. It got worse and worse until now I can only stream for an hour or two and the battery will be at 50% or less, even though it should have been charging. Sometimes I'll turn it on in the morning, after it had been plugged in and shut down overnight, and find the battery will be in the single digits even though it hadn't been used. I bought a new official Amazon Kindle charger a few months ago, thinking maybe that was the problem, but it's still the same issue. I've tried rebooting it - same problem. I tried deleting all the apps I never use - no improvement. Now it's gotten to the point where even when I fiddle with the charger and get it to start recharging, the recharging process is incredibly slow - it can take all day to get back up to 50%. I never had problems until maybe 6-7 months ago. How do I fix this?
My Fire all of a sudden started to do the fast battery drain as you've described. Just out of the blue a few days ago. I've spent the last 24 hours doing everything suggested that I could find on the Internet. Nothing worked.
Just now, however, the battery drain seems to have stopped. The most recent actions were to delete an app that wasn't working as expected and also to shut the wireless connection off, wait a minute and then turn it back on. It's now seems to be holding its charge when plugged in even though 30 minute ago the battery was draining even when plugged in! I am not a tech person at all, but it seems the shutting the wireless off, waiting and then turning it back on seems to have solved my problem. I won't know for sure until I unplug it from the charger and view how fast the battery drains when not plugged in.