Continued from my last post: The two AA charger worked pretty good on my phone. Running two apps ( one on standby and one with screen on ) the 2 AA-cell charger kept my phone's internal battery at full charge for ~ 4hrs. In practical use my phones' internal battery will run my Locus GPS app for ~3-3.5 hrs. and still have 30-40% battery left ( using the screen as briefly as I can ). Unless I start doing centuries or brevets ( very unlikely ) this should work for me.