Different power batteries?

[jforget1]

I bought the grip for the 350D and have 2 batteries I bought at sterlingtek as my primary set.
I am wondering if I can use the battery that came with the camera and pickup one more battery from Sterlintek even though they are different power. I don't remember exactly the power of each I just know they are not the same. Is it OK to mix these two as a backup set. I would think if I have 2 pairs of batteries at all times. I should be prepared for just about anything.

[Mitcon]

I use batteries with different mAh ratings in mine. No problems so far, I read it's safe to use batteries of different charge status. Besides, when I tested my Canon 7.4v 720mAh and the generic 7.2v 1500mAh batteries they both show 8.4v.

I think when two batteries of different charge status are used it will draw power from the higher charged battery untill both are equal and draw simultaneously there after. I think as long as the battery falls within the stipulated voltage theres no problem, the mAh rating is the time the battery can supply for.