Battery Charge time

[Sithel]

I've charged my FPZ a few times now and notice the light stays blue while charging then go to green when full. But these last couple times I used it until the battery went completely dead and shut down my fpz. Last night I charged for what seemed like at least 6 hours and the light never went green. So being scared of screwing it up I just unplugged it. Thinking maybe 1 of the batteries was the issue I unplugged 1 and ran just 1 battery until dead which seemed like about 2 hours of play time. Unplugged it and ran the other battery for about 2 hours until dead. So 4 hours on 2 batteries that are 1000mah each, so does 4 hours seem about right even though the green light never came on saying fully charged?

And out of curiosity, if i have 2000mah total and using the canakit 2.5a charger how long should it take to charge to full?