Battery Module Replacement - Some questions afterwards

Don't know. However, as a EE type, whenever I see "R" my thoughts go immediately to "Resistance", as in Ohm's Law. Resistance is a fact of life in any battery or any other power source, for that matter, and I happen to know that resistance goes up as a battery ages. Rb1 sounds like "Resistance of Battery 1" to me.

Consider ye ancient Carbon-Zinc D cell. Nominal output voltage with no load is around 1.6V. I haven't played engineering games with one of these, but I would expect that if one measures the output voltage with no load it would still be 1.6V until the point where it had gone beyond flat. However, the resistance would go up over time, so the actual output voltage would be something like

Vo = 1.6 - I*R(t)

where I is the current of the load on a cell and R(t) is the time-varying resistance, bigger as time moveth on.

(You'll also notice that I*I*R = Power Dissipated In The Battery, which explains why the back of your cell phone gets warm when you're doing something interesting. And that includes putting current into a rechargeable battery.)

So, given that there's bitty computers busy monitoring the health of the cells in the Prius battery pack I could easily imagine that said computers are doing a little math and working out the resistance of the cells over time. Or your fancy app is doing it, either way.

Lower values of Rb, then, would indicate a healthier battery. Those values could be in Ohms... But I wouldn't be surprised if they were in milliOhms. Or some scaled number that makes sense to the software.

Oh, yeah: The Big Power guys will tell you that the ultimate limit on how much power an AC power generator can make is determined by how fast one can get the heat out of the generator when it's generating power. The amount of heat is determined by I*I*R, where I is the load current of said generator and R is the resistance of the wires inside. Which is one of the reasons that Big Power Guys hope that room-temperature superconductors will arrive someday and make R, and the generators, tiny.

KBeck