Click here to get a new TI-Nspire rechargeable battery on eBay.
I’ve put together simple video tutorial on how to change the rechargeable battery on the TI-Nspire CX (or CX CAS). You won’t need anything but a set of mini screwdrivers and a new battery. As I say in the video, this is a fairly simple procedure which I’ve done many times without any problems. However, any time you take the calculator apart, there is a chance something could go wrong, so proceed at your own risk.
You could end up needing to do a battery pull for several reasons. Sometimes, the Nspire is acting strange, and a factory reset doesn’t do the trick. I’ve also had occasions where the battery meter reading 25% when the battery was actually completely charged, and a battery pull seems to reset the meter.
On the other hand, if your old rechargeable battery is shot, it’s not expensive to change out for a new one. The same battery that works for the older TI-Nspire Touchpad models in grayscale will also work the the CX models. Here is is on Amazon for under $20, which is the norm. If you’re more of an Ebay shopper, you can get it here.