Wiring Diagram Charging configuration for Pershing
The wiring diagram above can be used to switch between charging the batteries and running the tank without having to open the tank to charge the batteries.
Notice the DMD and MF units are hard-wired together to the switch to avoid bulky connectors that take up precious real estate.
The charging switch is a DPDT (double-pole double-throw) to disconnect both terminals of the electronics to ensure safety when charging. The battery plug is connected to the battery(s) and the charging plug accepts the charging unit. Pay special attention to the polarity (red and black wires) when making connections and verify the switch is making and breaking contacts correctly with an Ohm meter before connecting battery power.
Extreme care should be excersied if hard-wiring more than one battery pack together. With charged or even partially charged batteries, a short circuit across battery wires can be damaging to the batteries and to oneself. Use of Y-connectors can be used for multiple battery packs but will take up more space. If more than one battery pack is used, it is imperative to use the same mili-amp-hour rating and manufacturer when parrallel charging as damage may occur to the batteries if not so matched. Also very important is to trickle charge the batteries only. Do not fast charge the batteries. The heat build-up while installed in the tank may cause damage.
Try to locate the charging switch in an accessible location like under the drivers hatch or any place that can be accessed without removing the turret or hull of the tank. Likewise for the charging plug, being able to charge the batteries without dismantling the tank will save time and keep the model looking good and not like its in the shop for repairs.
Charging connector Tiger I under hatch Charging switch and Battery connector Charging switch Tiger I under hatch
Charging switch and connector for Tiger II with charger attached
Pershing charging switch and internally wired brass accessory towing eyes for charger connection
by Mike Gardiner
Southeast Armored Division
Tech Notes - Page 4