I switched from 2x3S 2200mah lipos and 10" props (got about 6 mins also) to 4S 5000mah lipo with 9" props and now get 11 minutes moderate flying. I use an EZOSD current sensor which displays on the goggles how much mah you've used so you can fly right till the end (about 4000mah to leave 20% in).