Before I added the calendar mentioned earlier, my battery life between charges was about six weeks. That was with the Kindle on stand-by (Press the power button and release it to go to stand-by.). Battery life may have been longer, yet, if I had turned the Kindle "off" fully (Press and hold the power button until the green light begins to flash.). After adding the calendar application, I need to recharge the Kindle about every seven days, perhaps more often. (Update: Since installing the new firmware update mentioned in Step 3, battery life is much, much longer; even with the calendar.)
There is a battery bar in the upper right of the screen. When the battery is nearly discharged a low battery warning does appear. Many recommend letting the battery discharge fully once a month to avoid any possible memory problems with the battery's charge level.
The charging voltage is 5 volts and up to about 2 amps. maximum. Kindles come with a USB cord so you can charge yours from the USB port on your computer. You can also buy chargers that convert AC current for the USB cord or convert 12 volt DC current from your car's cigarette lighter to 5 volts for charging the Kindle. I discovered the phone charger for my wife's current cell phone has the correct Micro-B USB end and I can also use it to charge my Kindle. See the photo. The USB cord that comes with the Kindle is necessary for viewing and manipulating files on your Kindle through your computer. When the Kindle is charged the amber light turns green. Charging time is about 3 hours.
Batteries take only so many charging cycles and they need replacement. At this link
you can find a video on replacing the battery in a Kindle Touch yourself. Information is also given on where to order a new battery and a tool kit for opening the Kindle.