Kindle Battery Life

I just completed testing my Kindle Touch 3G with wireless off. The test conditions were as follows:

• Wireless off except for 5-10 minute periods to sync and check for new items
• Wireless usually Wi-Fi but occasionally 3G
• Reading periods of 5 minutes to an hour
• Some use of the reading light on the Amazon Lighted Cover for Kindle Touch

Unfortunately, I blew it toward the end of the test when the battery was down to about 40% by leaving wireless on overnight by mistake. In the morning the charge was down to about 10%. By that time I had logged 23.25 hours of reading. That matches up well with Amazon's claim of 30 hours battery life with wireless off based on 30 minutes per day for two months.

I'm partway through a test with wireless left on continuously with a strong Wi-Fi connection. So far I have 5.65 hours logged with about 30% left on the battery indicator. It looks like I'll fall a little short of Amazon's claim of 10.5 hours with wireless on, based on 30 minutes per day for three weeks.

The difficulty of testing battery life with wireless on is that battery drain varies with the strength of the wireless signal. Data transfer slows down with weaker connections so that transferring a book or blog takes more time and uses up more battery.

My conclusions so far are that the battery on the Kindle Touch 3G will last through most wilderness trips as long as wireless is off. Using the light on the Amazon Lighted Cover for Kindle Touch seems to add little to the battery drain, which makes sense because the cover uses a single LED.

Since most backpack trips are a week or less, wilderness hikers should be able to read as much as they like, unless they read for hours on layover or storm days. River runners on extended trips (such as the full three week trip through the Grand Canyon) are going to need a way to recharge the Kindle, which usually means a solar charger. I'm going to look at some solar chargers over on my new blog, Travels With Kindle. I'll also look at travel accessories such as covers and sleeves.