Gen 1 Battery Rehydrating Experiment Results

I'm sorry to hear about the loss of your car. However, it is consistent with our greatest risk, accidents.

Bob Wilson

 

I've been in contact with Jeff. The 30ml is a typo. He added 3ml per cell.

 

How often does the battery need to be re-hydrated after the initial procedure is done I wonder? I am going to perform this on my car.

 

Didn't the OP confirm it worked already or am I missing something? I am doing a grid charger reconditioning as well.

 

Hi All, Interesting thread. I am organizing funding to develop module level battery regeneration in combination with cell level re hydration. I am considering plastic (nylon) screws dipped in JB Weld epoxy as the sealant for the NiMH module rework. I am an M.I.T> EE with a commercially developed 12KW lead acid desulfator that has 6S and 8S NiMH profiles built in , tested at University MSc level.
I see 3mL or so water re hydration is suggested. I don't see why a bit more won't be beneficial in terms of venting longevity. Hot water is a good idea as it enhances KoH crystals back into solution. I have had success using sonic cavitation with lead sulphate crystals to enhance their destruction. I did this version of the desulphator for bloke, down under...

I hope to achieve the same to accelerate the reconstitution of KOH solution via cavitation agitation.
This is the new theory of cavitation in electrochemistry
Electro-Sonication - Ultrasonic Electrodes

 

Good luck but my experience:

1. Mechanical sealing fails - the Toyota patent cites plastic welding and I continue to believe this is the only practical approach.
2. Sealing terminal seals is a hard problem - the loss of hydrogen via the terminal seals remains a hard problem that stopped me. In effect, the "O" ring around the terminal leaks the small amount of electrolyzed gas over time. There is no significant loss of KOH but the electrolyzed, water gas of hydrogen and possibly oxygen.

My last thoughts were to drill out the safety vent and put a 'nipple' that lowers the peak pressure and retains/recombines the electrolyzed gasses. This can also provide a valve for water reinfection. Not trivial, it provides an 'after market' solution for rehydration and reduced gas loss.

Bob Wilson

 

So far sealing with a 4-40 steel screw results in at least 1 leak per blade. Resolved with plumbers teflon threadseal on the screw.
My first trial didn't yield much (5%) AH improvement using a 10% NaOH electolyte (7ml) .
Will give the cell another cycle later.
Running another trial with just 10ml water and unsealed cells. That will allow excess water to evap. and enhance the dissolution of the KOH crystals better.