First off, I'm no expert at this. So the info I give is only based on my own experience. Hopefully someone else will chime in with some info/fact also for comparison.

I get 11.3v on the dx7 after 12 hours of charging, but I can't really say how long it last before the alarm trigger. But I have used it for at least 2.5 hours without going below 10.0v. I have not used it very much yet beouse I only have 2 helis using the dx7.

I have other transmitters also for some other helis and planes, and they also get to 11.3v after charging for 12 hours. One of them (Hitec Optic 6) gives me 3-4 hours of flying before the alarm starts, but it has less mah on the battery.