good day!
I think common ang battery drain problem sa generic or china made battery grips for nikon d40/d40xd60/d3000. Ang akoa kay para sa ako d40, over night lang nga walay gamit ma drain jud ang he battery... I met someone who figured out the problem and took the risk nga ipa mod sa iya. Karon ok na kaayo ang grip, dili na mu drain! Good thing is minimal kaayo iya charge! Paid only P250 for the mod! And I would recommend the guy.
If nahan mu ma check or ma mod inyo grip, puede ra ninyo contact ang guy directy.
09336243497- Marvin
HTH