O'Reilly logo

Canon EOS 40D Guide to Digital Photography by David D. Busch

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Replacing Your Clock Battery

In addition to the large rechargeable lithium ion battery that provides most of the power for your Canon EOS 40D, a second battery nestles in the same compartment to provide enough power to retain your current settings and preferences, as well as the local date and time. This coin-sized clock battery is a long-lived C2016 3-volt lithium manganese dioxide cell, located in a slide-out carrier near the hinge of the battery door, shown in Figure 9.4.

Figure 9.4. Your clock battery is located in the main battery compartment.

You may never notice this battery at all, as it may last several years without needing replacement. ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required