I removed the battery but kept the I2C chip/pcb, and fed 5V from USB port via a diode, on the PCB battery connections, seems to work fine. I actually installed a single wire from USB VCC to diode then + battery terminal. But you need to power the Kindle from something that can deliver at least 1.5A for startup peaks. A USB hub does the job fine in my case, and also connects it to a raspberry pi for ssh through USB networking, so no wifi either. Use a good USB cable for power.