My Canon 50D is always on. What can I do to minimise battery loss?

Get the On-Off switch fixed?

Sounds reasonable, however I’m on a several months long trip, unlikely to stay long enough in one place to get it fixed. In addition, few places I’ve visited have camera stores that could fix it. I’d like to know what I can do now, before returning home where I can have it fixed.

When it’s switched on and in a backpack for a day trip, it’s easy for it to accidentally hit the live view switch, wasting battery.

To disable Live View, under the [Setup 2 (yellow wrench)] menu tab, select [Live View function settings] → [Live View shoot.] → 'Disable'

It's on page 116 of the EOS 50D Instruction Manual.

Before packing your camera away you may also want to set one or several or all of the following to minimize battery usage from buttons accidentally pressed:

• Turn off Image Stabilization via the switch on the lens, if applicable.
• Set the MF/AF switch on the lens to MF, if applicable.
• Set [C.Fn III -3: AF point selection method] to [1: Multi-controller direct] so that a press of the multi-controller does not bring up the Quick Control screen.
• Set [Shooting (red camera) tab 1: Shoot w/out card] to [Off] and remove the memory card from the camera.
• Set [Shooting (red camera) tab 1: Review time] to [Off] so that an accidental image taken will not display the photo on the LCD.
• Set Drive Mode to [Single shooting]
• Set the Mode Dial to [Disable Flash] to prevent the flash from popping up and firing.
• Set [AF mode] to [One Shot]
• Set [Setup (yellow wrench) tab 3: Flash control] → [Flash firing] to [Disable]
• Set [Setup (yellow wrench) tab 2: LCD brightness] to the minimum value.
• Set [C.Fn IV -1: Shutter button/AF-ON button] to [4: Metering + AF Start/Disable] so nothing will happen when the AF-ON button is accidentally pressed.
• Set [C.Fn IV -3: Assign SET button] to [0: Normal (disabled)] so nothing will happen when the SET button is accidentally pressed.

From any of the P-Tv-Av-M modes you can set all of the above suggested settings (with the obvious exceptions of setting the mode dial to [Disable Flash] and setting the lens to 'MF' and turning IS off) and then register them to the < C1 > or < C2 > user settings. Use [Shooting Menu (yellow wrench) tab 3: Camera User Setting] → [Register] to set the 'C1' or 'C2' mode dial position to the selected settings. It's on page 186 of the EOS 50D Instruction Manual.

You can then use the other positions on the camera's mode dial to set the camera however you would like with regard to those settings. When you get ready to put the camera away, turn the mode dial to 'C1' or 'C2' (whichever one you registered) and those settings will all take effect without having to change them individually. Later turning the mode dial back to another position should restore all of the altered settings back to where they were before you moved the mode dial to the 'C1' or 'C2' position.

Beyond that, you can crack open the memory card door or the battery door and the camera will not power up until they have been properly shut. The battery door is easily removable to facilitate the use of a battery grip. Just be sure to not break the tiny plastic tabs on either of those doors that must press a switch in the body when the doors are closed for the camera to power up.