2002 Prius battery refurbishment underway; how many modules should I replace?

Thank you for giving some good details. You definitely have a Battery assembly that does not need to be replaced and refurbishing it is the most reasonable action to take. You are doing great so far.

What I see in what you have shown is that you have 4 modules that I recommend you replace.
#3 is undoubtedly bad
#9 is also bad by looking at its performance in charging and discharging voltages.
#5 appears to be good everywhere accept for in the load test. it might be on its way to failing.
#16 is a good module but some discrepancy in the figures, that come close to creating an out of balance SOC (state of charge), could mean that it might begin failing in the future.

When I refurbished the Battery Assemble on my 2003 Gen1 (240k miles on the original battery assembly), it was very similar to your situation. I replaced 5 modules, 3 of which were bad, and 2 had discrepancies that made them questionable for future reliability.
The Battery assembly and charging system perform perfectly now, and after well over 2 years of operation since the refurbishment, the estimated lifetime reading still sets at 92%.

In regard to module placement in the assembly, it is easier for me to describe the modules as "cells" since the assembly is made up of 38 cells, 19 modules of 2 cells which are divided into blocks. I put similar and matching cells together in the same modules. I put the modules of best readings and condition in the middle and the others to the outside. I did this mostly in consideration of heat and cooling.

I hope this helps you out.

 

As long as you're looking at your time is about free then by all means you have free labor and plenty of it and the space to work on and do your thing I shouldn't be any problem how did the bus bars and the nuts look those seem to be very important on these assemblies usually your bus bars are turning black by now and the nuts holding the bus bars to the plates and all of that are frosted and look like general h e l l. Sometimes rectifying that can make amazing things happen all of a sudden but then again that's a lot of nuts a lot of bus bars etc but if you have the time and your labor is not worth that much to you than by all means I mean to me at the time I spent $1,300 at the dealer so 1486 whatever it was that seemed to be like a smoking deal be done in 5 minutes drop it in the car and drive 13 more years so that's what we did I didn't have the time as you.

 

In answer to the question posed in the title of this thread.............
ALL of them. Seriously.

And rather than rehash a discussion that has already been beat to death on here many times.............
You could have done a search and some reading ahead of time.
Really.

 

If this includes labor, a $3k new Toyota pack replacement isn't bad for a car with only 65k miles on it. If replace by Toyota I recall that includes a two year warranty on a battery pack that should last another ten plus years.

 

Yes I paid 1460 ish . And did the 50 minute install myself I realize I don't get the two-year warranty but I don't think I'm going to need it and if I really pushed at my local Toyota dealer where I bought the batter they would probably warranty it for me if it was a clear fail so I'm not too worried about that they know me pretty well over there and don't give me too much grief and there's a big paper trail I mean in reality at the end of the day it doesn't matter who dropped the battery in and connected to relays and put the plug back in right No because if you mess that up initially you would never get the car out of the stall or create a fire or whatever happened so there would be no two years to make

 

I paid about the same and did the DYI install, but last time I checked price has gone up over $2k for the part. The Toyota parts departments I used is currently listing it as "This Product Is Not Currently Available".

 

Yeah I've heard that lately that's the deal out of stock classified as new old stock if you can find it all that business I did find a Panasonic cells new I cannot remember what the deal is on them per piece but still I guess if I have to do that and buy a set of bus bars and nuts we could do that but right now I don't have to do anything everything's done so we're waiting on another one to fail I guess I've got a G3 with the cord stored for the battery issue and it doesn't like to go into EV mode until it's been running a few minutes to charge up and it's a junkyard battery that I got two three years ago and just dropped it in this 2010 and it's been driving Uber and all that nonsense through the pandemic cars hardly ever at home or stopped I guess that's why it's not blown up and keeps running It seems as soon as you stop one of these things for a few minutes all the problems start so if you're running one of these a taxi or a delivery vehicle might go to 666 and just croak or a little less if it's sitting at home going to work and coming back I guess all this can come on a lot quicker It just seemingly seems that way.

 

Last I checked the Panasonic cells in the correct amount we're about $1,300