Frequently when I take the D700 and grip out for some fast shooting, after only a few sequences I'll notice a slowing in the frame rate. When I check the grip battery in the control panel display (which showed a full BP 30 seconds ago), has dropped to 2 bars (out of the five). More often than not if I unscrew the grip thumbscrew and just break the connection of the contacts, and then reattach the grip, the 5 bars come right back. This morning I noticed that the same can happen if I just pull the batteries out of the end of the grip (and then reinsert them).
I use Duracell Ultra Power cells, but I've seen the same thing happen in the past with standard Duracells.
Has anyone else seen this happen. It's not a major problem, but I would prefer not to have to unscrew the grip every few minutes.