Does the drain plug have the same thread size as a new std size element found at Home Depot or Lowes? Why not use a standard element ?? Cannot be adapted ??
There is a member at RVnet that was building 12v elements for those that wanted to use them with secondary solar power loads. The Hotrod or Lighning Rod aftermarket heaters sell for less than $100 in kit form with switch, thermostat, and necessary wires. Either of these solutions are superior to cutting the tank and using a residential element.