Which of My Hybrid Battery Cells Are Mandatory to Replace? (Voltage Data in Post)

Both are true, but it is not as cut and dry. The 0.3-0.5 V and the 1.0-1.2 V thresholds come into play in different scenarios and Toyota is not sharing how exactly they interplay.

Looking at your static voltages, you likely have 2 modules at a minimum to replace one in block 3 and the other in block 8. But static voltages do not tell very much of the story. You will need to do a basic load test on each module (including the replacement modules) to learn the relative capacity of each module. You would then need to compile a battery with 20 modules that all matched in capacity. Through this process, you might find (many) more modules that need to be replaced.

As it stands, this battery is severely out of balance and just changing 2 - 4 modules likely will not yield a good repair.

You will need to invest in some equipment to charge and discharge the battery several times and in time to do that. It probably will take 2- 5 weeks of time to do the job to a good enough standard, but likely longer as you will be learning on the job. The amount of time will depend on the equipment you buy to match the process you choose.

Use the advanced search function to find many threads that outline the process.

Personally, I would not be bothering to take the amount of time to do this for varied reasons, not the least of which is the diminishing stock of suitable replacement modules. Instead, I would find 20 modules from a recently wrecked Lexus/Toyota with the same chemistry as yours (either NiMH or Li-Ion) and replace all modules. If they were very recent you wouldn't even need to do any charging or balancing.

Good luck, you have many decisions to make.

 

So, you have effectively done a complete discharge of the battery. Why?
All the blocks are well below 14.4 volts, which would be two modules together at the NiMH 7.2 volt plateau.
That battery wouldn't do anything for the car right now, except trigger fault codes.
Obviously block 3 has discharged to the point that (likely) one cell in one of the modules has failed.
Did you have codes that indicated block 3 was weak?

 

That is not balancing, it is equalizing and is largely a waste of time.

What you propose to do will likely not result in a successful outcome.

 

This is a good example of people who don't know any better repeating something they heard on the internet.

'If' and 'should' being the operative words.

BTW, I believe the Prius c has 20 modules in its battery, so you might get lucky to find two packs out of late model Prius c's.