Hiee Don,
haha forget to ask you this.....
I have seen your setup and seems that you always have your grip on...like its glued there already. Care to check you gold contacts on the battery and the one in the batteyr grip to see if there are grimes or dirt or dust layer that may have accumulated through time.
The Resisivity change on the gold contacts on your grip will result in bad "voltage" guestimation by the body and the bad dirty contacts on the battery will cause bad "charge voltage" guestimation for the charging sense circuit to shut off. Through time, you battery charge cycle will be shorter and shorter if you do not ensure good contacts(clean...)
rgds,
sulhan