I've charged it OUT of the Tx with the leads from my multi meter. I wouldn't suggest doing it all the time.
A 2 cell lipo is 8.4v fully charged, a 2 cell Life is 6.6 (I think). Anyway, the TX is expecting 4.2v fully charged, so my guess is anything over 5v would be bad, and maybe even let out some magic smoke.
Normally I just charge mine when I'm not going to be using it for awhile. From about 3.7v to fully charged it takes a couple of hours with a 2amp 5v charger connected to the tx. I once tried a 2.5amp charger, but started to get some electron smell and turned that off real fast.
There are 10 types of people in this world. Those that understand binary and those that don't.
