Re-hydrating the battery modules.

But during the first few cycles with holes open to heat up the modules that may also will boil off some of water and then it will have even less left?

Maybe better should i fill with John's method and then every cycle i can weight them, that may also will be useful info, first i will weight them before re-hydration, then i will fill them and weight again and again after every input of charge 9200mAh?

And we still don't know that if with John's method the vent will open quicker
also we don't know maybe when they are new the plates are covered above with the gel electrolyte

Also i think after a filing with John's method even if it will vent the half of injected water with some KOH that would be still fine, the member Jeff K that drove 20k miles he injected to he's dried modules only a water without KOH and he did not has any issue, and time by time i can monitor the internal resistance in techstream so if it will vent out a lot of KOH then maybe the resistance will increase.


Brad, thanks for warning about KOH safety

Alex.

 

Wonderful thread guys.

I have only one (perhaps useless) thought to throw out: if KOH deposits are seen in dead cells, it sort of implies that the venting was of water. So perhaps all that is needed is to replace distilled water and let the dry deposits return to solution. On the flip side, if a fairly concentrated KOH solution is used, the concentration may continue to rise as the deposits return to solution.

 

Hi John - Roy from Canada reporting on my progress with re-hydrating a complete 38 module battery.

I have just finished reinstalling the re-hydrated battery after replacing a module that had a reversed cell. I made the mistake of not sealing the cells while charging the battery installed in the car and some solution boiled out of some cells and caused a ground on the battery. Had to remove battery from car again and remove all modules and clean and repaint the metal as the solution ate the painted surface of the enclosure. One last thing I added was to cover all the screw heads that plugged the 6 filling holes in each module with a dab of liquid electrical tape, this made sure there was a good seal, electrically isolated the screws and will stop the screws from working out over time . I did a test run up and down my test hill and found the battery was much stronger in that the voltage drop on going up the hill was less then before re-hydration and the current draw going up the hill went from 60 amps to 69 amps (peddle to the floor in both cases). I am going to repeat and record the test again with techstream as I then will have a before and after re-hydrating comparison. For those that have techstream I may be able to post the before and after recording files that they could run in their techstream software.

I also bench tested 2 more modules before and after re-hydration. With a 9000mah charge I got 6500mah discharge capacity (round figures) on both modules. Before rehydration I could only get around 5400mah on each module. I will take pictures later showing the re-hydrated battery, the screws and the liquid tape can I used for the final seal.

Roy

 

That's a good idea, i can try this right now on one of my screws, since the screws are very small will be enough to add few flakes of KOH(of size like the screw) and some drops of water?

 

Hope that's enough KOH i added, tomorrow will check and update if something changed
the screws i bought through eBay and the material was described as 12.9 grade steel



Update:

a day after, nothing happened to the screw.

Alex.

 

John - these batteries are generation 2 not generation 1 - they came from my friend who rebuilds batteries and were ones that he determined were not good enough for his rebuilding process. I have no idea what the ages of these batteries are as they came from many different gen 2 batteries. I still have 3 - 2001 prius cars with generation one modules that have not been re-hydrated that are running well I will convert them to gen 2 modules as they fail. I have purchased a spare Gen 1 battery box complete with the computer and relay box that I am now going to rebuild with generation 2 modules, this will allow a quick swap so my daughter and my wife will only have a short time without their cars.

 

-

 

-

 

I wont probably need anymore - I have 230 Gen 2 modules to work with as well as the the Gen 1 modules (3 x 38) that are in the cars. He is not wanting to re-hydrate at this time but he may try it at a later date.

 

-

 

-

 

-