Re-hydrating the battery modules.

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Finally received all the items, and started the re-hydration!
i will update this post as will have something new.

The first what i did is cut the length of drill bit to make it short enough to not touch the plates of module!

The drill bits that i used have diameter 1.2mm



As marks for holes i used the letter on the modules, you can see in the photo below, the inject hole will be above letters "es" of word gases and the middle drain hole will be near the Japanese letter




After when complete with holes i weighted all the modules

Spoiler: Weight of modules in grams before re-hydration

#1 1032
#2 1037
#3 1032
#4 1032
#5 1035
#6 1037
#7 1034
#8 1037
#9 1036
#10 1035
#11 1033
#12 1035
#13 1029
#14 1035
#15 1034
#16 1034
#17 1035
#18 1035
#19 1032
#20 1033
#21 1031
#22 1033
#23 1033
#24 1029
#25 1033
#26 1034
#27 1033
#28 1033
#29 1031
#30 1029
#31 1034
#32 1037
#33 1036
#34 1035
#35 1034
#36 1034
#37 1035
#38 1038
#39 1037
#40 1037

Here my capacity to compare

Spoiler: Capacity in mAh before re-hydration

#1 5212
#2 4939
#3 3844
#4 3704
#5 3983
#6 3513
#7 3277
#8 3045
#9 2084
#10 2223
#11 1939
#12 1908
#13 1643
#14 1468
#15 1616
#16 1200
#17 1279
#18 1217
#19 1209
#20 1066
#21 1510
#22 1028
#23 1290
#24 1245
#25 1686
#26 1611
#27 1695
#28 1589
#29 1845
#30 1638
#31 1807
#32 2322
#33 2448
#34 2469
#35 2405
#36 2672
#37 3488
#38 3696
#39 4442
#40 4989

Now preparing for injection, and same i did to the needle, i left it length about 6mm



Mixed all the KOH that i have left that's about in 400grams, in a 2Lt de-mineralized water



injected the first four, as John said with a edge risen about 2inch(5cm), now i will leave them 30 minutes vertical and after 30 minutes horizontal without but without edge risen, and then will weight them again



Later injected all the other modules so they will have a lot of time to soak of the mixture

During injection i discovered that the mixture can be injected even fast as 20ml in 15sec! that's mean the liquid can travel very fast between cells

After many cycles i did not seen any results in recovery, i suspect in my case is corrosion of electrode or electrode deterioration, and looks like in that case is impossible to restore the modules

tapping thread & sealing

After tapping threads i added some silicone for better sealant



I suspect i damaged the threads on first few modules by turning the screws more than needed, will hope they are okay...

Alex.

 

I don't know maybe i injected too fast, i tried slowly but after a 5ml it started going out from injection hole i waited and tried again and same happened, then i pushed the needle very tight and injected faster until it go out from drain hole

Now i will leave them vertical 30 minutes after horizontal 30 minutes and then will try inject again but without risen edge, after will weight them again! to see how much injected in every module, i picked a strongest and weakest modules (5Ah-1Ah)

Alex.

 

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Hi Alex,

Have you made any more progress? I have a couple of suggestions to help speed things up. Do not add more charge than 1 1/2 to twice the discharge. After a 1400 mAh discharge any charge more than 2100 mAh is just going to heat and boiling off the electrolyte. A charge of 2800 mAh would give plenty of cushion to ensure that the module is fully charged. The amount of charge can be increased as you see the discharge increase. Discharging at 0.7 A is painfully slow. Set up a headlight for discharge. Time from full to 6.0 volts and watch for the time to increase with each cycle. Do not go below 6.0 volts. These changes could reduce a cycle from about 5 hours to just one hour.

Some modules can not be saved by re-hydrating. Two good examples are the first Gen that I sawed the top off and the second Gen module that I put screws in to measure each cell voltage. Both of the modules had weak cells that suffered from self discharge and maybe cell reversal. I will not reuse any module that can not hold at over 7 volts in long term storage. Have any of your modules fallen below 7 volts just from sitting unused?

Brad

 

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Did about 7 cycles with stoping the charge by delta peak, and still zero improvement... almost lost all my hopes have one last idea, to cycle until they loose the weight to original then may add little water again and try again to cycle, to do this faster i may set them charging all the day without capacity cut-off at low current to make them heat a lot, if still nothing then will refill them again and will place the battery pack back to the car maybe there will happen something, the car will cycle all the pack al lot faster...

I also have thoughts that may they not improved at all, before when i cycled them i charged at 0.7A the maximum voltage that they reached then was about 8.7-8.8, now at 3A they reaching 9.05-9.20, so maybe from here are the extra mAh that i got? i'll try at end again charge at 0.7A

I don't understand how you recovered them from few cycles

Here some measurements maybe will be useful
From outside top to the plates is about 17.5mm


The thickness of plastic is about 2.2mm, i got screws length 5mm according to previous measurements that Roy did, he said is 4.4mm




Alex.

 

Hi Alex - you have very good pictures and filling and testing data congratulations.

You were wondering how others were able to get better discharge readings. I have found modules that test in the very low ( 1000 mah to 2000mah) to be not usable and I do not use them. To combine a 1Ah with a 5 Ah will cause the code 3006 to come up when you put the assembled battery in your car as I have tried that with modules much closer in capacity. The 1 Ah will have a lower voltage on heavy current loads then the rest and cause the 3006 code.

The modules I filled were done in the car and a little solution boiled out of them under testing - this brought up the code 3009 (ground on battery). I removed all modules and cleaned them reinstalled and code did not come back.

The code 3006 (unbalanced module pairs) is still coming up once in a while on my re-hydrated battery and I have been driving it over a week now. The minivic shows on freeze fame that a week module group still exists but is getting better as time goes on.

Note - all the modules in the battery modules I re-hydrated in the car tested around 5500 mah dry before being installed in the car, each took about 3 cycles to get to 5500 discharge.

However- about a year ago I did recycle some gen 1 modules (dry) and their discharge numbers were between 3000 and 4000 mah and they worked out OK and are still running to-day with no codes. Note - at the beginning I kept getting code 3006 and just keep resetting the code and running the car gently.

 

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Alex - I did not know the information about up to 97 cycles and they improve - I probably threw out modules that could have recovered. It will be interesting to let me know know if you pair 1Ah with 5Ah and battery works OK.

The DTC POA7F is a code that does not come up with the minivic but it appears to be saying the the samething unbalanced modules. Did the code disappear after 10000KM?

You indicate that the middle modules see more load, but the cells are all in series so they see the same load currents - however the middle modules get hotter then the outside modules and thus may deteriorate faster.

 

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Hi Alex,

Have you been running these modules in your car for the last two months? Or, have they been sitting unused for the last two months since your last charge cycle? It is a big difference as a car will keep the modules charged. Your very low capacity modules likely have a cell that self discharged and reverse charged. Re-hydration has not been shown to fix self discharge or cell reversal. I will not use any module that can not hold at over 7 volts indefinitely. They just do not work well. I tested the 5 good cells of my topless Gen I module at over 6 Ahr. If I had run the test including the bad cell the results would be much lower.

Brad