I'd guess that it's not fully charging your battery. Even at a 5 amp charge rate(which is a bit more than your SuperBrain can actually charge at), it can take as long as 30-40 minutes to fully charge a pack of 3000's(that's what it took for me when I used 3000's, & I was charging at 5 amps on my Novak Millenium then). Something else toconsider, is your pack getting warm at all when you pull it off the charger? That's usually one of the most obvious signs that it's fully charged, the pack should be slightly warm to the touch(just a little above room temperature, maybe as much as 130-140 degrees F absolute max). If this isn't happening, I'd try putting it back on the charger & see how it goes.....
Tamiya TRF417, TA05v.2, TRF211XM, M-05ver.2R, XRAY X12