I've been wanting to start reconditioning prius batteries for some side income and want some feedback on my tools and procedures.

Tools:
I already have two hitec x4 pro's from my RC days , a 100 amp load tester from harbor freight , hybrid reporter/assistant and an old Integy Indi 16x7 that had been sitting in the garage for years.

Procedure:
First thing I do is analyze the health of the battery , the best way I have found to do this is to first do a visual inspection of the battery modules , then I measure their resting voltages . I insert the battery I'm reconditioning into my prius, force charge it then I drive in reverse until engine kicks on then I drive the car normally for 10 minutes I record the data using Hybrid Assistant. I take the battery off , put it on my table and discharge the modules at 20A using my Integy charger and record capacity , this thing is a beast It's actually faster for me to use the single channel Integy to discharge the modules than to use the 8 channels of my two Hitec x4's. Although I could use all three chargers simultaneously and discharge the pack even faster I don't because I'm sure there will be variations of capacity readings because they are different chargers and because of the discharge power 1.6A vs 20A .. I then use the x4's to cycle the modules If I'm sleeping otherwise I use them just to charge and I discharge them manually with the Indy , I work from home and my table is in my room so It's not as bad as it sounds. With my current setup it takes ~5 hours to charge the whole pack , and ~6 hours to discharge it. Once the modules reach 5800 mah on their discharge I stop cycling them and match the highest capacity ones with the lowest capacity ones in a block and then I arrange the blocks with the highest average capacity in the center of the pack with the lowest capacity ones being at the extremes , my maximum acceptable capacity differential is 3%. Once all of that is done I install the battery in my prius and do the same tests I did at the beginning and make sure the voltage under load is tight and uniform.

So far I have only spent $40 on the miniVCI cable and am open to spending on extra equipment that would help me make the process more efficient. I am unsure if I should go down the road of accumulating more x4's they are good chargers but they discharge too slow and I can't find anything close to the discharge power of the Integy in a quad port factor. Also if possible I would want to avoid the step in which I load test the battery in my prius or at least only having to do it at least as possible , especially considering that I have a gen 3 prius so I have to swap all the gen 2 modules into the gen 3 case in order to load test it then swap out the modules again so I can drive the car to run errands, and swap them again for the final test drive then back into their gen 2 case. Out of the 5 batteries I reconditioned 4 of them were from a gen 2 so that was fun... Is there any hardware/software that can log data like Hybrid Reporter but outside of the car? Would using the 100A load tester for let's say 30 seconds and recording resting V and the voltage on the 30 second mark be an appropriate load test? Thanks you guys for the help I appreciate it.

 

All you'll get from me:

Can discharge all 28 modules simultaneously at 20A
Can charge all 28 modules simultaneously at 10A (can do higher, but it's a strain on the AC circuit, and I have to utilize a second)
Can log all charge/discharge data
Can conduct the main operations that completely recondition a pack in less than 24 hours, but I take the full 24 hours for scheduling convenience. Entire process takes 3-4 weeks. Testing towards the end of the process disrupts other pack processing, so I have packs come out in surges. I replace 5-6 modules on average.

Pro-tips:

Of the three main performance parameters, capacity is the least important parameter for matching.
Beware all Gen3 (including 07+ Camry and all Lexus). Unless you're in a mild climate, Gen3 packs often have very high fallout due to module heat/cycle damage.

 

Interesting I never thought of charging the modules higher than 1C , believed it would not be safe. I'm guessing you use a device that can taper current at certain voltage thresholds , thanks I'll play around certain voltages and see what works best.

Yeah my process take about 2-3 days but I also keep the battery for an extra week because I like to test drive it and look at it's self-discharge levels. Is the extra 2-3 weeks rest periods you give them in order to get a better picture of the self-discharge?

The main parameter I use for matching is voltage under load then capacity and finally internal resistance , I take it I should start placing more importance on internal resistance.

I'm from southern CA doesn't get more mild than that , one thing I did notice about the camry and it might've been a one time thing , but the modules seem to get much more beat up than the prius ones , I'm wondering if toyota uses a different BMS because I have never seen a pack in such bad shape less than half of the modules were useable.

 

Camry is 3rd generation. You've just seen what most 2010+ Prius look like unless they've been babied in a very mild climate.