5D battery load tests

Disclaimer: don't try this at home, folks. I'm an electronics engineer, I know perfectly well what I'm doing.
------------------------------

Today I connected my 5D to a laboratory power supply, in order to measure its supply current. In order to compare directly to the camera's battery, I adjusted the supply voltage to 7.4 volts, instead of 6 volts as marked on the camera body. Several Dyxum forum members have been running their 5Ds and 7Ds at 7.4 volts without trouble, so I felt safe to do so as well. These are not highly accurate measurements, because my current meter isn't the fastest. Here are my findings:

- Standby power = 180 mA (as long as the camera is on)
- Off = .05 mA (probably data retention)
- Auto power off = .25 mA

- LCD on = 145 mA (*1)
- LCD on but blanked = 100 mA (*2)
- LCD brightness adjustment = no difference
- Viewfinder backlight on = 5 mA
- Shutter halfpressed = 25 mA
- Flash charging (2 s) = 1200 mA apx (*3)
- Shutter open = 200 mA
- Focus motor running = 300 mA (apx)
- Anti-shake on (during shutter open) = 550mA (*4)

To calculate battery runtime, divide you battery's capacity (mAh) by the different currents (mA) from the list added up, the result will be the runtime in hours (h).

For instance: runtime when viewing images will be 1500 mAh / (180 mA + 145 mA) = 4.6 h.

Conclusions:

*1: Letting the camera switch off the LCD automatically is going to make a big difference, you'll gain 45% run time
*2: Switching off the LCD manually (using the display button or the eyepiece sensor) will only blank it, and not turn it off completely, wasting 36% power until the "LCD backlight" timer expires
*3: Flash consumes lots of juice, but only in short bursts
*4: Anti-shake for long exposures seriously drains the battery

I hope these tests will enable you to use your battery's capacity more efficiently.

If anyone has a special request for a specific test, please let me know.


Edited by Fuzzbass - 11 May 2006 at 20:42

That really is useful, Fuzzbass - thank you!

Can I check one point with you. Does the "auto power off = 0 mA" mean that there's no advantage to turning off the camera manually (other than the risk that it will be inadvertently turned on by touching the shutter release button)? I have wondered, because it is very convenient to use the standby feature..

Great measurements!

I guess we all know that AS consumes a lot of energy and that you shouldn't use it in long exposures anyway...

Would you be able to measure power drain during power on/off? Gary Friedman advises to use the auto power-off during longer sessions since it bypasses turning the camera on/off all the time, and it does make sense to me. I'm just wondering how much of a difference it would be.

Regards,
Bart    

Thank you FuzzBass for sharing these results, they are great!
I checked Gary Friedman's book and I notice differences, but he measured 7D, not 5D (and he make a mistake: he wrote the values in Amperes but he wrote the symbol "mA"). Anyway, he didn't do so accurate measurements.
And I have a question: when I keep the shutter halfpressed and AS is on(sometimes I do this for seconds...), does it consume those extra 350mA for AS? Or the AS activate only when shutter open?

PS: I think Diddlbiker refer to those peaks necessary to initialise/"save-the-current-state of " the camera when you turn on/off from the power button.

Edited by icss - 15 May 2006 at 09:15

@didlbiker
Less power you spend if you use a auto-power-off, because when you do hard-power off, focus goes to infinity and on power on checks a state. So, there is this 300mA mentioned above for AF motor. When a camera is in "sleep", focus position is manintined an it not moves on half-pressed button. Turn it off only when you pack it in bag.

I confess I hardly ever turn off when changing lenses and I've not had a lot of problems with dust on the sensor; after all, there is a focal plane shutter between the sensor and the open skies...

Bob

thats great piece of information, wonderful!