I have had my Kindle Fire HDX for over 4 years now and I like it a lot. It is my go-to device for social media, email and web browsing while at home. Recently the battery has been lasting only a few hours - previously it would last over a week of normal usage. So I decided to replace it. I found a deal on ebay for about $25.00 which is a LOT cheaper than replacing or upgrading to a new tablet! I found a instructions on ifixit that shows how to open up the Kindle and replace the battery and it did seem a bit daunting, but I'm an engineer dammit! It turned out to be quite challenging, but I got it done without ruining the tablet. At one point I did puncture the batteries (there are 2) and smelled a strong solvent odor, but nothing exploded or got hot so I proceeded. Those batteries are glued in there quite firmly, and it took about 15 minutes to pry them free. Replacing them and re-assembling the case was relatively easy.
From a sustainability standpoint I'm pleased with the outcome. I can responsibly recycle the old batteries at Lowe's. Also I'm not contributing the the consumer culture that drives people to upgrade their devices every year or so. Plus I have delayed the day that I will have to recycle this great tablet, and I saved a bunch of money. I do wonder how these things are taken apart and recycled given how much trouble I had.
Here's a brief photo summary of what I did:
Here is the replacement battery and the relatively useless tools that came with it.
The blue spudgers broke and I ended up using a flat blade screw driver and my trusty Swiss Army knife to pry the case open. There was a tiny specialty screw driver tool that was needed to remove 4 small internal screws, but it was for a smaller screw. I was able to grind down the tip to make it fit.
Here's the case opened up and the display disconnected and off to the left.
You can see that I had to do horrible things to remove the batteries!
Here's the back of the device after I got them out.
I don't recommend this for the faint of heart or those not "tool enabled".