Re-hydrating the battery modules.

My question is why would you have to re-hydrate a sealed module? I am reconditioning a pack. I have only worked on two modules. Many of the modules on one side that have not been charged or discharged have a small amount of liquid forming on the plastic below the terminal towards the bottom of the module. I rolled the pack over to get to the nuts on the underside of the pack. This may have put pressure on the terminals on one side. I do not know. Has anyone encountered this situation. If a drop of fluid comes out of a module, would that mean that module needs to be discarded? Example of problem - https://share.icloud.com/photos/08f8Pu0-07BDih5cV_vEH646Q The liquid looks blue but I think that is a reflection of a nearby object.

 

The bus bars had been removed so I don’t think it could have come from that. Do you have a feel for this as a problem? Have you ever heard of this before? I went and checked the pack a moment ago. I felt the terminal posts and they were wet. The weather here is wet and very humid. I would imagine the humidity is close to 100%. It has warmed up in the last several hours. If the battery pack is cooler than the surrounding air it is very possible that the liquid could be condensation.

 

That looks like purple/pink ink on the end of that flange, and it looks damp all the way to the end. The blue color in the "deeper" part could just be pigment migrating from that ink throughout the fluid, and it only looks blue in the part thick enough to reflect a significant amount of colored light.

Does the blue fluid occur in any area without that ink?

 

Group 6 seems lower than group 5 you rehydrated. I probably choose 6 instead..
Anyways... almost a year since you did this stuff.. Any issues so far? and by re-hydrating, are you referring only to injecting distilled water or the solution indicated at the beginning of this thread?
I had order already the "potassium Hydroxide" from Amazon, arriving next week, so I have 13 modules I can use for testing or trying to recover them. Most of them weight ~1032g and those I bought from ebay to replace them weight between 1036 to 1044g. The only strange situation I saw is that many of my batteries that still have very good capacity, they measure between 1032-1034g, similar to those with no capacity (~0.500 mAh)

 

My first attempt was witha solution of demineralized water and caustic soda I drove about 45 days.
The modules developed an even higher resistance ( up to 33 ohm) after a few days, I guess the demineralized water was the problem. Distilled water should have been used. Further I noticed increased bubbling and module inflation immediately after the injection, my understanding is that the factory hydrolite gel is made to minimize bubbling.
I have replaced the modules with newer ones ( not new)

 

Thanks for the reply! I am trying using distilled water and 10% of Potassium Hydroxide, but I am encountering same situation as Alex @a_triant. I am in the process of charging/discharging 2nd battery from those I replaced, hoping I can get good results on some of them..

I am getting entertained with the process. 4 modules I got them drilled to pop the valve. The first module I injected air with my battery portable compressor with automatic pressure set at 150PSI... around 100psi it exploded from one side.. well at least it could be tear down. to see more inside them.
For the rest of the modules I clamp them between woods to prevent the explosion, and then paused the compressor at 85psi, 90, and at 95 were after 2 seconds it started to inflate the balloon i placed on the vent valve. So the other 2 did the same and all of them; the valves opened at around 95-96psi and closed again at 80psi.
So the first one I started charging, could not accept so much charge with my tenergy T180 because its Vdelta setting was 5mv and it stopped charging with only 500mAh pushed in. So I continued the cycle like, discharging to 5.4v, and last to 3V... charged and discharged to obtain capacity but it did not changed from its original 700mAh. Same as with Alex, resting voltage was around 7.7v.
Then I changed deltaV setting to my charger to 25mv so it will not stop so early, and leaved it charging for 3 hours at 3A... Voltage rised at around 9.20v... Discharged it back to 6V... but still around 700mAh capacity. I checked with my thermal camera and the cell near to the negative post was slighly colder than the other 5, so I am concluding that cell is bad beyond repair. The other 5 cells were just struggling to dissipate with heat the current I was pushing, but that weak cell never responded.