Can I borrow your battery charger/balancer/reconditioner?

Well then you are right. It is WORSE than I expected.

But in the 6 cell "modules", one high resistance cell will only prevent you from charging the other 5......not the other 162.

Things like this have been tried over and over and over since the first rechargeable battery was ever made.
The success has increased only slightly with the various generations of battery chemistry.

It is not economical, and maybe not even practically possible, to use chemicals that are 100% pure when making a battery.
Those tiny little contaminations tend to react in unfavorable ways with the desirable chemicals and over time turn into compounds that do not contribute to the desired storage of electricity.
Once those undesirable compounds form, the can NOT be turned back into their original components simply by passing current through it.

Regardless of the marketing hype and how badly people WANT an easy way to magically "reform" a brand new battery from an old worn out one.......the laws of chemistry and physics can't be defeated in any meaningful way.

 

Please, Sam. Present EVIDENCE to back up your statements. In this entire thread all we've gotten is your negative OPINIONS and that is not factually helpful at all. Presenting actual evidence from reliable sources will give us all a chance to review and compare the evidence against our current sources. Most of us are willing to change our views on this provided reliable evidence warrants it.

 

Just ignore him. I do.

 

You're not alone.

And it is definitely not an exclusive club.

 

I was actually alive when the original research was done on this......but that was long enough ago that it was not "archived" in an electronic form.

What I am saying is NOT an idle opinion. It is a scientific fact.
If you are REALLY serious, do your own research.
Because the information is kind of old, it won't be really easy.....but not impossible either.

Read my most recent post again ........and think about it.
Ask a chemist.....if you can find one.
Ask a few companies that MAKE rechargeable batteries.

The thing about marketing claims and urban myths is:
With each new generation, the old becomes new again.
If you never knew about this discussion being had 60 years ago......and 40 years ago.......and 20 years ago......
it all sounds new to you now.

But the bottom is that I don't really give a TLRA whether you believe it or not.
I am trying to give you useful information, based on a LOT of years of hard experience.
Take it or leave it but don't waste everybody's time in arguing about it.

 

Congratulations gentlemen.
Welcome to the "Don't confuse me with facts because my mind is already made up." club.

 

That older science has been replaced as technology and knowledge has improved. At one time the best scientists in the world also claimed the earth was flat and heavier than air craft couldn't fly. Do you still believe that despite newer evidence and proof? The chemical side is discussed in newer research; the newer conclusions are balancing is beneficial and can be scientifically shown to be beneficial.

I spent over 40 years in pharmaceuticals. Things are being accomplished today that were deemed impossible 20 years ago. Drugs that were deemed safe have since been found not to be. Others have been improved over their original form.

Things change.

 

Here's a paper on cell balancing from 15 years ago:

https://www.renesas.com/us/en/www/doc/application-note/an141.pdf

 

Congratulations Sam.
The pot calling the kettle black.

If you really were paying attention, you have read multiple times where this situation arises and people are advised the module is unrecoverable and needs to be replaced. it is not the situation when the module is just unbalanced. An unbalanced module is recoverable.

Nobody is claiming this process 'magically "reform{s}" a brand new battery from an old worn-out one.' Maybe if you would get off your high horse and open your mind you might begin to understand what is being talked about. What this process is doing is unlocking the unused capacity, that happens over time, so it can be used again.

If you have never tried the process, you cannot really be making claims that you are. I might not be able to give chapter and verse right now that explains why it works from a scientific perspective, but I sure have done my own research to know there is a scientific explanation.

Further, having a Prius that was showing the initial signs of an HV battery on the decline 4 years ago, and having used just one round of the charge/discharge regime as detailed by Hybrid Automotive at that time, it woke the battery up and I saw immediate improvements. These improvements were measurable and lasting. Better fuel economy, better power, and a slowing in both the rate at which the HV battery charges and discharges, among a few. In doing a basic charge and discharge test, recording in Techstream, I can demonstrate both an improvement in the time it takes to both charge and discharge. Again this improvement is the slowing of charge and discharge. I have repeated the process when required and have just completed my third treatment on this particular Prius. The driver for when to repeat the process I use is when the fuel economy deteriorates and it gets increasingly hard to pulse and glide plus the car begins to feel sluggish. So far each treatment wakes the battery up and the car returns to a more normal fuel economy and it is "peppier".

The claim I will make is not that the battery has been returned to like-new condition, but that the act of balancing has unlocked some of the capacity that was inaccessible. Another member here has demonstrated that an HV battery that has a measured 3 Ah capacity and is balanced, will, from a user perspective, appear to act more like the car did when it was new. This does not mean the battery is like new. To me, this says that balance is more important than capacity.

Will it continue to work forever? No, but I don't think anyone would ever claim it does. Some might think it, though, but they are incorrect.

You can continue to shout from the mountain tops that putting any effort into maintaining the HV battery is a big waste of time, but my experience over 4 years of putting time into maintaining the HV battery, I will continue to "waste" my time while I see a benefit. When I no longer see a benefit, I will replace the HV battery.

Take it or leave it but don't waste everybody's time arguing about it.

 

Thank you.
That elaborates in detail on exactly what I was saying.
Did you read the whole thing.....at least most of it ?

Highlites are:
The balancing routine “shunts” current around the cell that
needs balancing (the highest voltage cell).

Many circuits are required to implement a cell-balancing operation. This adds
complexity to the design.

Why Is An External Transistor Needed To
Keep Cells Balanced?

Pack Balancing Electronics
(End quotes)

NONE of that indicates that doing ANY operation on a whole pack at a time will accomplish anything useful.
Quite to the contrary, in fact.

Applied to the battery in a Prius......where it is apparently not practical to access the individual cells but only in modules of 6, ALL of the information, if you actually understand it, tends to indicate that any GOOD balancing is likely not possible.

 

In that article, the introduction gives a general overview of what balancing is and then very quickly begins and then continues to specifically discuss Li-Ion. It is acknowledged that Li-Ion is inherently more complicated, at least in my reading, and it is very hard to achieve the benefits of balancing.

We are talking about NiMH as it applies to Gen 2 and 3 Prius specifically.

With NiMH, it is not necessary to access the cells individually. The balancing is achieved by trickle charging at 0.05C (or less) which is gentle enough to allow fully charged cells to dissipate the heat of overcharging without causing damage while allowing the unbalanced cells to catch up.

Applied to the NiMH battery in a Prius even though it is not practical to access the individual cells (as is the case in a lot of NiMH applications, not just Prius) but only in modules of 6 or batteries of 168, all of the applicable information, if you actually understand it, indicates that balancing is absolutely possible.

 

From the same paper I posted and you just cited::

Conclusion

Cell balancing can increase the useable capacity to the system by more than 20% and can improve the life of the battery pack"

 

In Sam's defense though (somebody write down that I said that), it looks like the whole paper you posted is Li-ion-specific. That could weigh against generalizing to NiMH not just the difficulties, but also the reported upsides.

It would have been more to the point to post a reference that was about NiMH. I am sure there are such, and my dim recollection of them does align with your description of allowing the higher cells to tolerate a low-enough overcharge rate. But it would be better to link a source than to rely on my recollection.

For what it's worth, my Gen 1 definitely had a rebalance algorithm of some sort built into it. It would normally target the battery SoC right at 60% on the ScanGauge, rarely letting it below 40% or above 80%. But several times, while I owned it, usually several months apart, I would notice it continuing to charge at 80%, 85, 90, 95, 98, 99, and hold there for a longish period, and then avidly use electric power back down to the target 60%. (The MPG bargraph looked really impressive during that glide from 99% back down to 60%!)

 

One thing I gleaned about the li-ion, I gleaned from John Kelly's Prius Prime deep-dive, they are NOT easy or practical to dissassemble, down to the individual block level. He did do it to one of the units, but it required drilling something out, and it did not go back together easily, required a lot of jury-rigged clamping, and even then it was just barely doable.

 

I have linked multiple times in the past to Chapter 5 of Duracell's Technical Bulletin regarding NiMH performance specifications. The Battery University I've linked to also refers to Ni-MH battry charging.

 

WRONG.
Yes it IS.....to do it properly and to gain any significant improvement.
But it looks like you just aren't going to give up, even when faced with overwhelming evidence that refutes your position.
I don't understnd why this is so important to you.
But I don't really care either.
Others who are interested, however, need to know that what you are saying is NOT gospel.

 

IF done right.......as defined by the ENTIRE rest of the article.

 

Maybe. And more convincing to those who don't know the history or who can't seem to grasp the basic theory.
The basic principles have not changed much since the advent of the wet cell lead acid battery.

 

Reconditioning Nickel based batteries has been around since the tech rolled out.

https://mahaenergy.com/faq-c204fa/

What is conditioning?

The conditioning feature on the MH-C204F basically rejuvenates your batteries by first draining them and then charging them. By using this feature, your batteries will perform at their highest standards. Conditioning is also used to eliminate the memory effect which NiCD batteries suffer from.

How often should I condition my batteries?

For Nickel Metal Hydride (NiMH) batteries, conditioning is recommended once for every ten charges. For Nickel Cadmium (NiCD) batteries, conditioning is recommended every time you charge your batteries.

I have not used my NiMH batteries in several month and they are not holding their charge. How can I fix this?

NiMH batteries will self-discharge if left unused. Generally, within 30 to 60 days, batteries will become completely drained. When using them, you will need to first recharge them. After extended storage, you may need to condition (using the conditioning feature on PowerEx chargers like the MH-C204F) the batteries several times to regain nominal performance.

NEW! Powerex MH-C980 Charger
SKU: MH-C980

Deep battery conditioning system to revitalize old batteries

 

BUT ......does any of that make specific reference to balancing individual cells of a multi-cell battery pack ?
Or to trying to increase the performance of the battery by charging or discharging the whole thing as a unit to overcome an imbalance in the individual cells ??

I know that you are trying to be helpful here but there aren't enough hours in the day for me to go chasing links that folks post.......only to find that they don't apply to the discussion at hand.