Since the posting of Ken Myers 6th video on Deadrail Consisting has expanded it is time to start a new subject dedicated to Parallel Consist Wiring.
I have commented on Ken's attempt and my personal experience deadrailing using LocoFi in his posting which you can read we need to take this to another level.
This posting centers around why can't you have a single trailing battery car feeding power to multiple locomotives. Each locomotive could have two 22 AWG multi strand solid copper wires, red and black running from each end of the locomotive to the other and power feed wires coming from the battery car. Each locomotive's LocoFi system would tap into the power source wires running the length of the locomotive. Female receptacles could be camouflage in the body of the battery car and locomotives or in a small tool box on a walkway. The battery car would also have a batter charging receptacle mounted on it.
The Female receptacles between the battery car and the locomotives would be collected via a 2 wire cord with male plugs on each end, similar to real locomotives. Micro Mark micro mini connectors part # 86559 may work.
With this arrangement locomotives would not have to be facing in the same direction or only one locomotive could be used.
Since this is a concert I ask for comment and suggestions.
You could easily do it and it should work good. A 4S LIPO battery will be about 16.8 v fully charged and above 13 v when discharged. The main consideration is weight. LIPO batteries are about the lightest there is. You could go with a 1S or 2S LIPO and use a DC-DC converter to increase the voltage to whatever you want. A small DC -DC converter could be mounted in each loco and that way you don't have to worry about the voltage drop. A 4S 450 mili amp hr battery weighs about 2 oz. A 1000 mili amp battery is about 4 oz. Depending on your loco , you should be able to run 1 loco for almost 2 hrs on a 450 mili amp hr battery.