Charging many devices only takes plugging the appropriate cable into the battery. To charge my Nikon D300S batteries, I bought a generic 12V cigarette car charger for the Nikon EN-EL3 battery. I plug this into the cigarette adapter of my Sustain battery, and my battery starts charging.
When I'm going on a longer expedition or want more power options, I turn to Goal Zero (www.goalzero.com) for their extensive line of power packs, solar panels and flashlights to meet the needs of any photography assignment. They offer larger power packs like the Yeti 400, with 300 watts of continuous power. When used with the AC inverter, you can plug your 110V AC charger directly into the power pack. Goal Zero has a wide selection of solar panels that have simple cord diagrams to show you how to tether them together or plug them into your battery.
My favorite device from Goal Zero is the Sherpa 50 Recharger Kit with inverter. This kit comes with the Sherpa 50 battery, the Nomad 13 solar panel and a 110V inverter. I just plug in the Nomad 13 solar panel to the Sherpa 50 battery, and after six to eight hours of good sun, the battery is fully charged. But, here's the best part for photographers. Unlike many other solar systems, Goal Zero supplies a 110V inverter that attaches to the battery. I attach the inverter to my Sherpa 50 battery, and plug my Nikon D4 battery charger right into the unit. No fussing with special adapters—just plug it in like an AC wall outlet.
But the Goal Zero system doesn't stop there. When I'm headed to a remote backcountry area, I take the Scout 150 power pack and Nomad 27 solar panel with me. The Nomad 27 will charge the Scout 150 in about six hours with good sun. With the Scout 150 fully charged, I can run my laptop, sat phone and tablet for hours and hours. I use the Goal Zero Light-A-Life to illuminate my workspace. It's just like being at home.
(Editor's Note: Tom is working with older Goal Zero gear, some of which have been updated by Goal Zero. The Scout 150 is now the Escape 150, for example. See the Goal Zero website for the latest models.)