I bought a 4 Pack of these on eBay the other day. Don't have them yet. If anyone has experience with these chime in. You said "battery life" but what I think you meant, going by your 45 minutes between charges, I assume you meant, "Can I fly on these batteries?"

http://cgi.ebay.com/4-PACK-Volt-Watch-Battery-Monitor-FUTABA-JR-HITEC-GWS_W0QQitemZ380124849121QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item588134e3e1&_trksid=p3286 .c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1 205|240%3A1318|301%3A0|293%3A1|294%3A50