12v battery and charger for x-country trip

Hi everyone, I'm new to this Lipo and LiFePO4 stuff and could use a little help.
I'm planning a crosscountry trip using a velomobile and would like a battery that can power my accessories. There will be times when I will not be able to recharge for 2-3 days and the charging source will be 120v. The things to be powered include a MP3 player plus small speakers, automotive type GPS, cel phone, and LED head and tail lights which will be on 8-10 hours while rideing. The battery and charger must be as light as possible and as low cost as possible. I've been thinking about using three 12v 5ah battery packs in parellel from Hobbyking
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8580&aff=411978 What charger, keeping in mind that it must be 120v would you recommend? I would like to keep the charging time to a minimum if possible.
I have also contacted Ping and for a 12v15ah LiFePO4 battery with 5amp charger they want $227 shipped, but I'm hopeing that Lipo will be cheaper and lighter.
Any thoughts and other ideas will be greatly appreciated.
Thanks,
Dean

Would this charger work? At only 2amps it seems like the charging would be on the long side.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10946&aff=411978

I'd go with this one, or a similar B6 combined with a 5 amp power supply. Small light cheap, slow, but not as slow as the one you linked to. It'll do the job overnight. http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6478