PD or Iota for my upgrade?

Wayne Dohnal wrote:
Intuitively, I can't image why a DC source couldn't put the same power into a battery as it does to a resistive load

I also can see no reason why a DC source couldn't put the same power into a battery as it does into a resistive load. Everything I've read said that a battery is well modeled by a resistor in series with a perfect voltage source having zero resistance. That should make the load look purely resistive, although the resistance in the battery model may vary depending on the current flow. Of course, I'm willing to consider other information if I've missed something in my reading.

And, as a newbie here, I hope the conversation will remain at a friendly level even where viewpoints differ. I'm here to learn what I don't know, and share what I do.