I inherited an IPv4 a couple weeks ago from a buddy of mine. The battery indicator is vastly off. It's been off ever since I got it. I put my LG HG2s on the charger and they're half dead. But the battery indicator is showing it almost full. There is no option menu to calibrate either. If I put the batteries in my sigelei 150w, they read properly at half life. If I put them on my Efest charger, they show half full. It does it with both sets of married batteries I have.
