The built-in charger on the Tx pumps out a grueling 3C rate to the Lipo in the heli...It's no real wonder why the internal batts don't last long.
I've been considering a reroute to the battery (for external charging purposes) but not knowing enough about the electronics, I'm afraid that in doing so I might defeat the auto-cutoff (at the least)...So I've kept from doing so.
Even so, my Peak Charger (Duratrax Ice) has a minimum charge rate of 100ma (which is still 2C for the Picoo) so that' not much easier on the battery.
Didel makes a nice lipo charger (the "Bitcha") that can handle 10ma to 150ma in 10ma increments which is ideal here (you'd still have to mod/reroute the charging circuits), but that's an extra $40+ investment. Might be worthwhile though if you've got a few micro sized projects/flyers and use the 100mah or smaller lipos. Here's a good source for that Charger:
http://www.indoorflyer.co.uk/index.a...&productid=136