mongssim

If you can afford a better battery grip, you might want to consider the CGPro Battery Grip for Panasonic GH2 Built-in 5000mAh Li-ion Rechargeable Battery.

Cheers. :)

Looks like you are in luck.  You might want to order a CGPro Battery Grip for GH2. Link below.  Good luck.

Features:

• Compatible with Panasonic LUMIX DMC-GH2

• Extended run-time up to 7-9 hours.

• Built-in Ultra High Capacity 5000mAh Li-ion Rechargeable Battery
• Non-memory effect for maximum performance
• 4 level LED indicator for a quick check of remaining battery capacity.

Package includes:

1x CGPro Battery Grip Built-in 5000mAh Li-ion Rechargeable Battery
1x Charger

http://www.cinegearpro.com/hdmi-cables/power-batteries/cgpro-5000mah-li-ion-rechargeable-battery-grip-for-panasonic-lumix-dmc-gh2.html