Re-hydrating the battery modules.

Hi Brad - Your input is very valuable keep up the good work, I just noted the screws that are in the battery picture are in line with the walls of the batteries, some are on a slant and may allow water in and others may not. If some cells got more water then others they could overpower a weaker cell and cause a reversal which would cause the venting from overheating that cell or cells. This is only speculation but may have been the reason for the vent.

Roy from Canada








r

 

Pressure transducer wired to a chart recorder for that retro vibe, or an A/D input to a computer logging rapid samples otherwise.

This Dwyer seems to be offered in 17-4PH or 316 L for the wetted surfaces ... according to this chart the 316 appears better for KOH (though one would probably set it up so it sees nothing but air anyway).

-Chap

 

So that's mean the method how to fill from 1st post will not cover the top of plates and need search for another method right?
Then maybe will need to make the offset of second hole same like in the first hole so when the module laying on it side it can be filled more before the liquid will go out from hole, but that's again maybe will be not enough to cover the plates...
maybe then need to try a different angles while filling them

Looks like the easiest way is with 6 holes to fill them all above the plates and at same level.

Alex.
Thanks.

 

I will try again

Hi Brad - Your input is very valuable keep up the good work, I just noted the screws that are in your battery picture are in line with the walls of the batteries, some are on a slant and may allow water in and others may not. If some cells got more water then others they could overpower a weaker cell and cause a reversal which would cause the venting from overheating that cell or cells. This is only speculation but may have been the reason for the vent.

That makes sense John, this method of measuring the individual cell voltages is very good and I should have understood their purpose.

to ---- Brad_ sorry I brought up this observation, disregard my post.

Roy

 

Hi John - I have made a spare Gen1 battery using Gen 2 modules -installed it a while back -- as long as I drive it around town it has lasted about a month with no triangle of death code for the battery - however I recently took a 200 mile trip and the code for bank #9 ( #17 and #18 modules I think) came up and I had to reset the code 6 times during my trip( I had my computer with techstream with me). I may try to fill the bad modules in place with water or a solution once we have a method to fill the modules in place in the car.I monitored the battery during the trip and found that the code appeared after going up a steep hill and going down the other side of the hill the code came up. The load currents on the battery were not above 10 amps and the code appeared when the battery was charging on the downside of the hill at 13 to 15 amps. The voltage across modules 17 and 18 rose above the others by at least 1.5 to 2 volts which must have triggered the code.

Since I now have a spare car, I will use it as a test vechicle. I have the backseat removed so I have ready access to the battery by removing the fan cowing and the battery cover to do the experiments.

 

No John this one did not stick that might be because its a duff module that i have chucked in and out of a box & generally not been bothered how i treat it so i expect it was loosened, i think if it had not been moved out of a pack or treated very gently it would of stuck.

Richard

 

My other 3 cars have Gen 1 modules in them and they are working OK. It seems it is not how high a discharge capacity the modules have but how close their voltages are under heavy loads and charging. Modules 18 and 19 both had discharge values in the 5500 range with 5 amp discharge conditions before I installed them in the spare battery. My friend gave me some more Gen 2 modules and during our chat he mentioned the newer cars were triggering with as low as a 0.6 volt difference -- making his rebuilding of the batteries more difficult to sell as codes come up more easily.

Roy

 

In one car I have G1 modules that I recycled 3 times(over a year ago) and all 38 were in the 3000 to 3500 discharge range. this car has gone 15000 km and is still running with that battery. It has gone up to 800 km round trip jaunts and never thrown a code. Because this was the first of my 2001 prius purchases and I had no experience with the batteries I thought the battery was in good shape after the recycling. I would not trust that battery to-day ??? However I did use my highvoltage charger/discharger twice in a years period on that battery - this may have have made difference.

Techstream gives you the resistance of the paired modules (as you know).

The resistance readings I get in all my cars are usually 18 to 19 micro ohms.

Bad bank # 9 in the experimental battery is reading 19 , many others in the bank are reading 19 as well.?????

Once we have developed a method to add solution while battery is in the car I will proceed and test the results as you recommend. I have not made any experiments yet with the spare modules I have. But will do so in a few days as more knowledge accumulates. I wonder if Bob Wilson could join the discussion as he has conducted experiments similar to what we are doing and could also help us along the road.

Roy

 

Thank you for all the valuable information Britprius.

 

Good that you were communicating with Bob and you decided to carry on the process.

 

Here is a link to an old rehydrating thread.

Gen 1 Battery Rehydrating Experiment Results | PriusChat

One member reported getting 20,000 miles out of a rehydrated pack.

Brad

 

I read the post by jeffkay and found this paragraph from the post very interesting as it got him 20000 miles of driving ---


xxx "Small holes are drilled above each well. Boiling distilled water is injected via syringe--30ml each. The boiling water makes the grids or plates more likely to wick up some water. Panasonic used a gel originally but "re-gelling" them would be impossible...

Stainless steel screws are "self-threaded" right into the case after the water is insjected. I wanted to use some o-rings but got lazy. The screws can be opened in the future should you go to Death Valley once more. As Bob notes, The dissimilar plastic screw interface may leak vapors. But between the main vent opening and the fact that these batteries should not vent under normal conditions, I did not make any big deal over it. I did test melting chunks of a junk case into the holes with a simple soldering iron and it works great but is time consuming. May be the way to go if you are worried about leaks." xxx


Roy from Canada now ------

With his method I am going to try to re-hydrate one module installed in the battery of my car that is not performing as well as follows:
:
1) Using 3/8 in self tapping stainless steel screws drill into the top of each cell with the screw (using a power drill will make it fast).
2) Remove the screw (you only need to go down 1/4 inch to thread the hole)
3) Boil distilled water
4) Using a syringe marked at 10 mm from the end (so you do not touch the battery below and short it out) and insert 11 ml into each cell
5) Re-install the six screws
6) Drive the car and use my mini vic to see the difference in the modules battery voltage and resistance before and after re-hydration.

 

Roy, if you going to do 6 holes then i think better way is like John(Britprius) said in other thread:

"My intention is also to fill the cell and then draw off any water above the cell plates "the reason for using a plastic tube on the syringe". This will ensure all the cells have the same level of electrolyte at the end of the process.
As soon as I have found suitable positions to drill I will come back with details."

or you can do that with syringe needle, since you said before the depth from top to battery plates is 13.49 mm so you can make a mark on needle at 10mm example and with that way you will sure that you will not touch the plates and you will know that every cell you filled equally 3.49mm above the plates.

Alex.
Thanks.