Yet another gen II battery rebalance thread

So I have a 2005 gen II Prius. It has been driven around 230 000 km and the HV battery went bad on it this summer, actually exactly 7 minutes before the yearly car inspection..... Hahaha. xD At the same time we have moved into our first house and have been doing stuff to be able to get all our things into the house, among other things tearing down a wall to get our snowmobiles into the garage. Because of this the car has been sitting for a few months but I've driven it around a few times to give it some exercise. I have owned the car for about 3 years now.

So about a month back I started on the battery pack by looking up stuff on the internet and read and watched the information and videos in Prius High Voltage Battery Reconditioning | PriusChat, here on the forum. That was when I fell for the Turnigy charger since it was fairly cheap and apparently capable enough to do the work. Sadly the charger used in the video has been replaced by a newer Turnigy charger that, I later discovered, had been updated with a new software 2 years ago. The new software made it so that it was no longer able to set the capacity cut-off higher than 5000 mAh and so that it no longer stored the values after cycling DCHG > CHG. I thought I should start using it anyway while ordering a better one and this is the reason for the inconsistent maximum charge numbers near 7500 mAh in the attached file. I tried to make sure it wouldn't charge the modules with more than 7500mAh +- 250 mAh but I have to sleep and go to work.....

Together with the Turnigy I also used a PSU that was only able to deliver about 80 watts which has affected the charge rate that the modules have been charged with. I also got a complete (28 modules!!!) junkyard battery pack from another prius from the local Toyota dealership for free with, what looks to be, a lot of working modules. These will work as my replacement modules after I've reconditioned them as well.

The Turnigy charger settings have been:
Charge rate: 1.5 - 2.8 A (Depending on the weak PSU)
Discharge rate: 0.6 A (It couldn't discharge faster than this)
Discharge end voltage: 6.3 V
Voltage DELTA-PEAK: Default
Capacity cut-off: OFF (Could only reach 5000 mAh)
Safety timer: 720 min
The better charger, EV-PEAK CQ3 arrived early this week and I've been using it instead of the Turnigy one since then. This means that about 80% of the values in the spreadsheet are from the Turnigy and the rest are from the EV-PEAK, I've lost track of which. When I got the EV charger I started to look into this more and some document that seems to be written by someone from here and these threads:

Discharge rate and how low before Charging? | PriusChat

Gen II Prius Individual Battery Module Replacement | Page 2 | PriusChat

Another Gen II Rebalancing Thread | PriusChat

Prius Battery rebalance thread | PriusChat

That's when I discovered that I may have been doing mistakes like charging too slow and discharging too fast that makes me wonder if it will bite me further. I also find the information in the document and the threads confusing since no clear answers are given and decided to make my own thread. That is why I'm asking all the questions further down. So what I'm hoping for is to get detailed answers from one or some of the battery balancing gurus.

The EV charger settings are:
Charge rate: 5 A
Discharge rate: 1 A (Note that this differs from the Turnigy charger.)
Discharge end voltage: 6,0 V (Note that this is lower compared to the earlier setting on the Turnigy charger)
Voltage DELTA-PEAK: Default
Capacity cut-off: 7500 mAh
Safety timer: 720 min

Here is my spreadsheet:



So now that you know my situation, here are my questions:
1. Does the different discharge rates (0.6 A, 0.7 A or 1.5 A) affect the end result of the battery pack in a noteworthy manner?
2. What is the recommended discharge rate? In the document it says to use highest discharge setting available but then says to use 0.7 A in the aggressive
3. What happens to the modules if I increase the discharge rate?
4. Should I replace the low voltage (6.2 V to 6.3 V) modules even though it seems like they have recovered very well according to the spreadsheet?
5. Is it important to do the 3 cycles back-to-back without interruption? Some of my modules have been sitting for a week or two after completing the 2nd cycle since the Turnigy charger went above 7500 mAh on the 2nd charge. Had I thereafter begun a 3rd cycle they would've overcharged like, for example module 5.
6. Is module 5 garbage now that it has been so greatly overcharged?
7. Which modules would you suggest replacing and why? I want to learn.
8. How do you calculate the internal resistance of the modules? When in the whole battery pack balancing process do you do this? I need further details here as I find what has been written down earlier by others confusing. What voltages are used? The internal resistances in my spreadsheet are what I got from a battery analyzer.
9. How much wear have I put on my modules by mistakenly cycling them as mush as I've done?

It might be wiser to finish answering and discussing the first 4 questions and then go into the last questions to avoid extremely long posts from everybody.

Feel free to ask about missing information, I know some may be missing since I myself had a hard time compiling all this information and putting it in print myself.

Best regards, Rappa.

 

I would say that it was more a bummer than a huge bummer and a huge surprise. When I disassembled everything to get the battery pack out of the car, I noticed that some bolts were missing and that some of the modules had markings on them. Therefore I don't think that this is the original battery pack. It has probably been reconditioned or replaced before so I can't really say how old or how far it's been driven.

Hmm, then I think I'll lower the charge rate to 3 A instead of charging the modules at 5 A.

So far I have not found any settings for setting a max voltage cut-off. According to most threads and videos I've seen it seems like it hasn't been necessary for them either. I've seen that the charger have displayed voltages as high as 8.9 V while charging modules but have assumed that that meant that it's the charger voltage, not the battery voltage. Similar to how a normal charger would charge a 12V car battery with like 14 V or something.

I have not yet read about whack a mole, what is that?

Hmm, I'll get my hands on an OBDII scanner that supports DrPrius then. This is gonna get really interesting.

Ok then, I think we can go into the last 5 questions in my first post. Although I will add another question, question number 10:

10. Is it important that at least one of the 3 charge cycles that all modules will go through reach 7500 mAh? As you can see, some of mine hasn't is that an indicator of a bad module?

11. As you can see I have decided to switch out the 3 pink marked modules with better ones. After I've cycled through the modules in my other battery pack, is it necessary to make all the modules have the same voltage +- 5mV? How do I accomplish this, by discharging the modules to the same voltage with the charger? Is that precise enough?

Here is the now finished spreadsheet: