charging dead modules

Thank you.
Please continue posting your results. Great to hear of someone doing it on the cheap on an older car with a well worn battery. It seems most battery rebuilds replace all the modules at once, I have wondered if it would work to just replace modules as they fail, instead of all when they get to high miles.

 

The approach I used was to drill one hole and with the battery on the side, inject water until it stops accepting water. The water passes from cell-to-cell until the level reaches the hole.

I could never solve the problem of how to seal the hole including some tests with plastic welding. The problem was matching the plastic 'rod' to the original case material AND getting a good fusion weld. But I have another approach I'm planning.

The pressure release valve is useless. So drill out the pressure release valve in two modules. Lay them on the side and inject water until they are full. Then orient them upright and together so they can be wired in series and fit a clear plastic tube between the two pressure release nipples with small, screw, hose clamps. The theory is the plastic tube and clamps seal the modules only now the tube is the 'pressure relief.'

Do your normal initial charge and then individually charge/discharge each module to recover capacity. Once they both have near identical Ahr capacity, put them in series and use the 12 module setting in the 989 to complete charge/discharge cycling.

Bob Wilson

 

Actually I appreciate you doing your experiments even though there is a risk. It is the second and third experimenter who with the first discover something previously unknown.

I was thinking about this and if all 38 modules are configured in pairs with the hose, there is no need for the existing 'pipe' to the useless safety valves. There would be a potential risk from airflow restrictions so it makes sense to carefully monitor the battery temperatures if a full-pack were so configured.

Bob Wilson

 

Please be careful messing around with used modules.

Another shop showed me this battery a DIY'er tried to fix themselves. The Prius drove and kept coding, so the owner bought an AutoZone OBD2 scanner and just kept clearing the codes when they occurred. After a while the battery overheated and caught fire. The fire department had to be called to extinguish the blaze.

 

It is always a difficult decision:

• Don't share until 'trust' established - it presumes the one with knowledge also has the skills to evaluate the abilities of others.
• Share with caution - it presumes we are adults and understand that when one takes risks, no also accepts the consequences.

I originally heard about the water rehydration experiments in "Prius Technical Stuff" and could not get any technical details from the author. However, there was reference to the Toyota/Panasonic Patent and that was enough.

As I reported earlier, I was not able to solve the 'plastic welding' problem used in the Toyota/Panasonic patent. I had tried epoxy and a Harbor Freight 'plastic welding' kit. I knew stainless steel, sheet metal screws were at best temporary. But the other 'hard' problem is repairing the "O" rings that leak gas that is normally generated by NiMH operation.

Now I intend to test the proposed 'drill out the safety vent' and replace with plastic hose and clamps in a modified, electric bicycle configuration. It will also incorporate a shunt regulator of my own design. But I'll only be using eight modules at a time. Still, I'm not ready to publish anything until I actually 'do the experiment' but warm weather is approaching!

So was that pack from a western state guy or the Florida guy?

Bob Wilson

 

Had been wondering if there's a way to use those vent holes for refilling- great idea, thanks for sharing!