>however the 2 non branded batteries i have both show as 0 >(new) & indicate a 100% charge when inserted.. >tbh i've not used the camera enough to see if there's any real >world difference in the number of shots available..
Since the health reading is an indication of the battery's own chip, and since these knock-off manufacturer's can make their own chip, comparing the two is likely an exercise in futility. If I were a knock off maker, I might be tempted to program my chips to be very slow to say they were "old".
What's baffling to me is the (Nikon) one that went from 2 back to zero. On yours at 2, can you check it the next few charges, see if it stays at 2?