I think I've experienced low battery RTH a couple times lately. It's hard for me to tell if it's simply low battery or if it's signal lose. Does the Phantom 2 and Phantom 2 vision + actually have return to home upon low battery feature? It seems to have happened betweed 15-20%. I never mess with below 10%, and usually start coming back around 25% as a min. I don't go out of VLOS anyway, so it's usually a pretty short trip back to me. Cheers!