You are sorta right. The reason why the roadster is not able to handle DC current is because it does not have a high amperage Dc bypass that would allow the the direct current to charge the batteries directly avoiding the on board charger. All the power imputed for the roadster goes through the onboard charging system. In the model s there are two options for charging being the normal ac to dc conversion either 10 or 20 KW hour charging (depending on what you opt for) or a DC bypass that allows the 120KW to feed directly to the packs hence why the model s can be recharged so quickly. The roadster does not have the bypass hence it is limited to only a high amperage ac charging. In theory the replacement would seem simple but we always have to bear in mind safety and reliability we have over 460 volts flowing through a very finite although heavy duty cable that must interact with the internal battery management system to maintain optimal longevity for the battery packs.I didn't listen to the stockholder meeting but was told afterwards that he said the only significant reason it can't take DC is because it has the wrong kind of contactor. Did he actually say the Roadster never would be able to handle DC? The last time I had my PEM open it looked to me like a simple hardware kit could easily be installed to charge w/ DC. Then it's just a matter of replacing the contactor and related control circuit and firmware. It would not be 250 amps of course but the DC charger would handle that.