Hi there,

I thought I'll share some of good news as it may be interesting and relevant for this subforum readers.
At DitoGear™ we have recently developed a neat and simple piece of accessory for powering your Canon Cameras.

Essentailly it is a 12V -> 8.2V converter, designed for performance, efficiency and an mini-XLR-modified canon DC coupler.
The advantage of Canon coupler is that it does not give you any stupid messages in camera and shows the battery level.
Also it gives the necessary protections not to hurt your camera. You may give it a go with a cheap chinese or your own coupler, but since it is not THAT expensive, we believe that the Canon way is worth it.

More details here:
http://ditogear.com/store/accessories/4 ... 5d-7d.html

Is that a switching buck converter? Or just a simple voltage regulator? (ie, does it get hot and waste loads of energy?)

As I stated earlier, it has been designed for an optimum performance.
It has 87% efficiency in converting current, necessary protection systems as well as low-voltage auto cut off to prevent damaging the battery when the voltage level drops below 10.8V (a low limit for most batteries on the market).