Agree with Zren.
I have a similar staff, one side is VA the other DVA. Here's a shot of it I took literally this morning:
And the same two hilts side-by-side:
Can you tell which is which? :-) Yeah, me either. IN person it is easier, though. For the record, the one on the right in the staff shot and the one in the foreground on the paired shot is DVA, the other is VA.
DVA is a "bluer" version of VA, which is a mix of red and blue. Banes Heart is the same skewed toward red, btw. But what happens when your batteries are not quite fresh is that the blue fades first, because the blue LED takes more energy than the red to illuminate. So as your batteries fade, the color of the LED will shift toward red, becoming pure red just before the batteries go fully dead. (This is on stunts and ObLite set-ups only. LiIon setups have a buck puck capacitor that keeps the energy flow constant until it completely undervolts and the whole system dies, at which point you take the batteries out and charge them back up. One advantage of the LiIon setup - constant color)
Now, what you described sounded like very erratic power input because of the loose batteries. What you should see is a cool purple color, though it might flare to more pinkish VA toward the tip. As Zren said, I'd get a fresh set of batteries, then make sure they are secure, and see what happens. :-) Unfortunately, the mixed colors are not an exact science and they do tend to fluctuate a bit. Even if everything is perfect they might be slightly different. My very first saber was a Phantom V3 in Sentinel Yellow. One of them was perfect, a wonderful buttery yellow. The other one was just a tinge more golden, and it had a tendency to green-shift at the emitter and red-shift at the tip, so the first 2-3" of the blade were more of an acid yellow-green and the tip would be orange. :-) It just was what it was. That's one reason I got my current staff with one VA and one DVA. They're not the same and I don't expect it, but they're close. It seems like this is more "realistic" anyway, as no two crystals would be the same either.
Anyway, sorry to preach! I hope the fresh batteries yield the color you were hoping for! Please post a picture or two as well, maybe there's more to the story.