What are the Ryobi Charger Resistor Values inside the unit?

"That is an amazing question. Perhaps you can find part numbers or board manufacturer's names on the fried board, and cross reference that with other drill manufactures that may have used the board in their ni-cad or Li-on chargers.

Or, since you seem quite savvy on the e- end of things, perhaps just cut the Gordian Knot on this and build your own board with the proper voltage/amp/ohms outputs and wire it into the Ryobi interface pins. If you are good enough, which it sounds like you are, you can probably build in a smart circuit so as not to over charge and to battery tend while it is sitting around.

Just a suggestion,

Frank"