To me, an engineer, at least. For instance, among other strange things, it seems to show that the motor is simultaneously powering the wheels and regenerating the battery. Is this display supposed to be "correct" or just "notional". Am I being too picky about this?

The key to understanding this is the fact that there are TWO motors in the HSD. One is referred to as MG1 and the other is MG2. MG1 is basically a generator, and serves as the starter motor. MG2 is often referred to as the "traction motor" - it powers the wheels, and regenerates electricity during braking.

This is what allows the "motor" to be charging the battery and driving the wheels at the same time. The energy screen is basically combining the motors into one graphically. There are also modes where MG1 is directly supplying electricity to MG2 to drive the wheels rather than going through the battery first.

A very useful site for understanding the Prius' HSD is:

http://www.ecrostech.com/prius/original/PriusFrames.htm

Go to the "Understanding" link on the left. Each subheading has useful info, but there is a LOT of reading!

it seems to show that the motor is simultaneously powering the wheels and regenerating the battery.
I believe it does. When more hp is available than is needed for power the rest goes towards regin. When I am driving on rolling hills I have found that the right amount of throttle keeps me moving as well as driving my battery into the "Green" charge state.

OK. Thanks for the informative feedback. I have read all that and followed their hyperlinks to other places. I have also had a couple more weeks of driving around and watching the displays.

The essence of my problem is wrapped up in the TWO motors. The power display only shows one, and in an attempt to show some "cute" displays of what is happening, it becomes confusing and only "notional", at best. In other words, it is just the wrong level of detail. If they added the other moter, I bet it would be a great display

Ironically, there is actually a simpler display and I find if very informative without driving me nuts with things that make no sense. This is the simple animation in the multi-function display.

I think the electrical and mechanical power from the ICE or through the MG1 are show in different colors. So you can differentiate mechanical only ICE output from ICE/MG1 output.
J

Ironically, there is actually a simpler display and I find if very informative without driving me nuts with things that make no sense. This is the simple animation in the multi-function display.

The MFD is indeed more simple, but I'm not sure why you'd like it more then the Energy Screen. There is more detail there even though it does not show the 2nd motor. However it does show the engine mode where it drives the battery charge and the wheels. While you don't really need to watch this screen, it is additional information to help you understand this particular mode and under what circumstances it occurs.

Without out the NAV you are left wondering when the ICE is shown powering the wheels on the MFD is anything happening with the battery at the same time. And in many situations it is being charged.

Additionally if this information is useful then by having this on the NAV screen it leave the MFD available for other uses (then again using the MFD leaves the Nav available for say navigation!)

I think the best way to fill up the battery is to use regenerative energy from braking that could have been wasted anyway, rather than using the engine to charge it. There is energy efficiency factor as it is transferred from one place to another. Channeling engine power to MG1 to battery to MG2 is obviously not very efficient (could be as low as 35%). In contrast, the mechanical channel on the power-split-device can have as high as 99% efficiency.

Now if you just step on the gas to go up to slightly above traffic speed and allow lots of opportunity to coast and then pulse again, then you will be saving lots of fuel thru fuel cut off and and charge your battery through regeneration from coasting.

The same coasting in nonhybrid would require the engine to continue to run thus using unecessary fuel plus there is no regeneration of energy.

I think the best way to fill up the battery is to use regenerative energy from braking that could have been wasted anyway, rather than using the engine to charge it.
I'm just saying that there are times where a slight lift or push of the throttle makes all the difference in whether the ICE is charging the battery without a significant change in the FE gage. Without the Energy screen you are not aware of this mode.
Not a big deal but it's a tid bit of knowledge to know that when the ICE is on and driving the wheels there may be a side benefit of the battery being charged because the ICE is generating more HP than is needed for the current propulsion.

I agree that the braking is the BEST (more effecient) mode to charge. BUT if you want you can "force" some battery charge at times when you are using the ICE and there may be situations where that is beneficial.