got some young 2012 modules

That must be so satisfying having it turn out so well. A definite reward for your meticulous patience.

Good job!

 

I hope you'll be able to survey the old modules

Bob Wilson

 

Let me suggest you have:

• a good, multi-channel, charger
• knowledge of how to use it
• resources for a parallel charge

My thinking is survey the modules and hopefully share so you can compare and contrast the old and new modules. I am curious about how bad your old modules were. Then you can sell the unit, all modules balance charged, and the buyer is going in with 'eyes open.'

Bob Wilson

 

Although off-topic with regards to Prius I am interested to know what you did to your father's Insight battery.

 

Yes but you won't like it. The problem is old modules lose their water. Although we can add water the problem then becomes sealing up the hole. That defeated me but I have another approach I want to try someday.

Bob Wilson

 

But wasn't this pack working fine in your car just prior to this (like less than a month ago)?

 

But just so I can be absolutely clear in my understanding, wasn't the pack that your currently cycling installed and working in your car with no DTC's prior to replacing it with the 2012 modules?

 

Those are accurate numbers for worn out modules. Let me explain how they 'wear out' and how they can be recovered.

During normal operation, a little bit of the water separates into a small amount of hydrogen and oxygen. Normally this is not a problem because the cell will 'recombine' these gasses back into water. But in a worn out module, some of the gas, typically the hydrogen, leaks out the terminal seal. This is especially true if the module run hot from repeated charge and discharge cycles. The greater the cycle swing, the greater the heat and the weaker the terminal seals become.

Look closely at the middle pack modules and see if there is a black, smear around some of the terminals. That is the partially failed or failing "O" ring that normally keeps the hydrogen and oxygen gas inside the module.

The water is part of the electrolyte that carries the current through a plastic mesh that separates the positive and negative electrodes. But as the water disappears by electrolysis and gas escaping, the electrolyte begins to dry out. This forces the current to pass through a smaller area of the plastic separator which gets hot from the resistance heating. When it gets hot enough, the separator melts and shorts that module. But before that happens, less and less of the electrodes are in contact with 'wet' electrolyte. This reduces the module capacity, what you are seeing.

Years ago, I took some marginal modules and replicated an experimental technique to add water. Then using multiple charge-discharge cycles, I got the modules back to 'like new' capacity. But now I had the holes used to inject the water and closing them turned out to be where I stopped.

There is a Toyota/Panasonic patent that describes using "plastic welding". Tried and failed to get the holes closed using either heat or epoxy glues. Great modules but without being sealed, they soon dried out again.

Since then, I've got a new idea that involves drilling out the 'safety' valve and coupling two modules using plastic hose and hose clamps. The drilled out vent is used to add water and the hoses clamped to the nipples should make an air/water tight seal. Just I haven't done the experiment, yet.

Bob Wilson

 

When I cut off the top, I isolated the valve. I don't have the dimensions handy but it looks to be about 1/2".

As for adding water, the Toyota/Panasonic patent mentions using weight. In my case, I laid them on the side and waited until water dripped out. There is an 'air space' between each cell and the water flows easily across the tops. Just don't overfill.

Bob Wilson

 

I'm not so sure about "filing a claim with Ebay" for being "scammed".
Used batteries are sold on Ebay, usually listing voltage.
If the item description did not list the internal resistance, a buyer has no grounds to make resistance a condition of the sale after the fact.
Please be fair to the seller and to Ebay by limiting frivolous complaints.
When I buy Prius battery parts online, I am paying a deeply discounted price. I buy a few extras and have some to discard or experiment with. I do not expect the quality control I get when buying direct from Toytota, but I save a loooot of money.
Best way to avoid being scammed is to maintain a 75 foot buffer zone between yourself and Toyota service managers.