Expected mpg with bad hybrid battery

Yes, running the A/C increases the current draw to several amps from the traction battery. Suppose you see a 5 amp draw and you are initially at 60% SoC with the car in Ready but stuck in a traffic jam. ICE will kick on at about 45% SoC. That's 15% SoC * 6.5 amp-hour of battery capacity, let's round that up to 1 amp-hour of available battery capacity before ICE-on. 1 amp-hour is 60 amp-minutes. Divide by 5 amps, leaves you 12 minutes.

 

If you should happen to recondition the good modules, please post the resulting amp-hour capacity. The most worn battery I've looked at had 155,000 miles, but I was still able to get the modules up to 5.5-5.6 amp-hours capacity after three cycles. That's about 1% of actual capacity loss for every 10,000 miles. It would be nice to have more data points.

 

One of the disadvantages of the Prius' hybrid design compared to Honda's IMA mild hybrid implementation which can run even with a dead traction battery.

 

This is a good thing since the IMA batteries tend to last only 50,000 - 100,000 miles. But don't forget that there is no alternator, so something has to be done to keep the 12V charged.

 

IMA isn't a mild hybrid system.

 

I don't see any reason why the generator/converter can't charge the 12V even when the traction battery is dead.
The generator/converter replaces the alternator in the IMA.

 

IMA has a backup 12V starter. HSD does not. Even if it did, I don't believe the eCVT can be run properly without the traction battery, so the HSD vehicle would still be immobile.

 

The IMA battery powers the DC-DC converter. If the IMA battery is dead, then the DC-DC converter will not charge the 12V battery.

 

For instance, if the smaller motor/generator doesn't have at least some current in it providing a holding torque, then that motor will just spin when the engine does and the wheels will not get any torque at all.

 

Go for a long highway drive at speeds always in excess of 52mph. That is the mpg you would get without the HV pack.