Looked at the Plug-in Prius today (Pictures inside)

Yes.

Just think of 13-26% on the PHEV as the same target range of 40-80% on the hybrid.

Remember 13-26% on the PHEV will be about the same battery capacity as 40-80% on the hybrid. So it will function exactly the same as a regular Prius once the battery charge drops to that point.

No. You will always want to deplete the pack down to the charge sustaining mode. It doesn't matter if you do it the first half or the 2nd half of your long trip, but using it the 1st half guarantees you'll use most of the plug-in energy instead of gas.

 

Here is a possibility for the next Gen IV Prius:

PriusChat Forums - gmalis1's Album: gmalis1

 

No.
I agree with drees.
The plug-in's concept is trying to drive as long as possible EV range (depletion mode), then it is going to be like a regular hybrid using 13-26% SOC (same capacity as regular 40-80% Prius) called sustaining mode.

Ken@Japan

 

I think of it like this, after the PHV battery has been depleted 70%, it will "revert" to a standard prius battery, and the ICE charging routine will also revert accordingly to normal hybrid mode.
But regenerative braking will be able to take the battery to a higher SOC while in normal hybrid mode. Allowing additional depletion mode duration.
What an advantage that will be!

Engine efficientcy will not be sacrificed to maintain a higher than normal (necessary) hybrid-mode battery SOC. But regenerative braking can increase SOC back into depletion mode.

 

It is based on following my post.

The regular Prius has 1.3kWh(0.2kV X 6.5Ah) battery and the usable capacity is 0.52kWh(80-40%:40% of total).
Assuming the plug-in has 3 times capacity (3.9kWh), the 13.3%(26.6-13.3%) of total is the same 0.52kWh usable capacity.

Ken@Japan

 

I can not tell you much more, but I can tell you the capacity is 5 kWh.
That much as been released to public knowledge already.

Ken is on the right track...