I prefer a power panel because it's amazing the difference in power needed to drive various plugs to the same brightness. The lead acid battery inside the box is the type used in alarm systems and most auto electricians have them as well as the LHS. I recharge mine every few months from a standard wall charger and just monitor the voltage until it starts to level out. Works for me .

The item in the middle is my "fuel pump", non-electrical squeeze bottle from my CL days.

The item on the right is my starter and is also non-electrical. It runs on hamburgers, chocolates, milkshakes etc and I've never forgotten to take it to the field with me.