Lithium Iron Phosphate is the future, the system of electric cars,1400 charge cycles and the Meon LiFe is an off the shelf solution - pay for it, plug it in and use it. I will head for a LiFe system when I build a new lighter cart but in the meantime I use a simple lead gel solution. A lead gel battery with a PSU across it. That is it: A 44ah battery in a strong bag (mikesfilmsound.com/new_itemB12.htm), an XP Power AC to DC PSU, (JPM120PS13, www.xppower.com/pdfs/SF_JPM.pdf). It is fan free, 85 to 260v input, so works both sides of the pond, adjusted to 13.7v so it charges and floats the battery without needing regulation and none of my gear is upset with 13.7v. It is smooth and free of noise. It also works as an uninterruptable power supply when the mains is pulled and fully charged it gives a day in the field without AC power. I also use the odd DC DC converter that take 9 - 18v input and give a steady 12v for equipment that does not like a lead gel giving 10.5v at the end of the day. If you used a DC DC converter to regulate all of your power, then rather than float the battery, you could use a fast charger - knowing that the higher boost charge voltage will not get through to your equipment. The battery costs £105 / $168 and the PSU £50 / $80. Simple and reliable - many of us have used this system for years. I also have a fast charger that I use overnight if I have been mains-free all day and the battery needs a complete charge - about $100. Remember that lead gel batteries are rated using a low discharge rate. With a higher discharge rate a 44ah might actually be a 38ah. Expect capacity to drop over the years and if it is frozen outside bring your batteries in overnight as a lead gel at freezing will halve its capacity and will not fully charge when that cold. Cold is when Lithium chemistry comes into its own and I am looking forward to a lighter higher capacity future - admittedly, at a higher cost.