There has been a lot of talk on DPreview about building portable power systems like the Vagablond. I decided to put one together myself. I got the Samlex 300 Watt inverter for $118 from here. I then bought two 12V 12Ah batteries from Walmart designed for kid cars ($35 each). The charger is 1.5amps @ 15V. I got it from Toys R US for $20- also intended for kid cars. I put the whole thing in an Ammo box and here is the result. I did a test and I got 275 full power flashes with my 900 Ws Flashpoint 1820 monolight before the low voltage alarm started to sound. These were continues flashes too, every 4 seconds as soon as the strobe recharged. I think this is a worst case scenario as I wouldn't ever shoot that way. If I had gone slower, I think I could have gotten more. The inverter buzzes a bit while it's charging and I talked to Samlex who said this means it's being pushed to it's max. If I were doing it again, I'd get the 600 Watt version. It also gets a little warm but has it's own cooling fan that kicks on and if I stop shooting for a couple of min, it cools right back down and the fan switches off. I thought about wiring the AC plug and the charging plug to the outside of the box so that I could access them with the box closed but decided that it would be safer to leave them inside thereby requiring the lid to be open which allows the batteries to vent. The batteries are Sealed Lead Acid but this is a big warning on the side to not charge them in an air tight enclosure. Over all, I'm really happy with it and recommend anyone who want to take their lights on location to give it a try.