Inconsistent Hybrid battery readings

sounds like the classic whack a mole. sometimes you just need a new battery

 

There really is a skill in rebuilding a battery properly, it's not as easy and fast as what you've described.

Since you seem to have all the right equipment to do this, you should let the battery sit a week before taking any measurements, so it'll allow to discharge. The bad modules will discharge a lot more than good modules.

Afterward you can load test the good ones and see if they are all good. Then button everything back up with all good modules and balance the entire pack using your charger/discharger

 

Think of it like this. When your battery was brand new, it was like having 28 brand new 'D' cell batteries. The HV battery ecu continuously monitors the 14 block voltages looking for a voltage difference between blocks that exceeds its setpoint threshold. Over the years, with thousands of temperature cycles and thousands of discharge/charge cycles, those 'D' cell batteries have degraded. Some are now 'C' cells, some are 'AA' cells and some are 'AAA' cells. Since the car uses only a very small band of capacity during normal operation, the car can usually function just fine with those cells. Unfortunately, one dropped down to a 'hearing aid' battery with very little capacity or had an internal failure. That's the one that finally tripped the threshold and coded the battery. That is the one you found that was 6.x volts. What did you replace it with? If you replaced it with a module that is a 'D' cell, then those 4 or 5 'AAA' cells are now going to randomly trigger the threshold. Even though they would probably work fine if a 'C' or 'AA' used module was installed, a replacement module that has a high capacity will make the others look weaker than they really are. Hence the term whack-a-mole. This shows the importance of matching a replacement module to the estimated average capacity of the remaining original modules.

Pick 28 random people off the street and line them up side by side, with their height differences monitored by a computer. Remove the shortest one from the lineup and replace him with Lebron James. The computer does not trigger a code for being too tall, because it only looks for "too short". Now, the new shortest guy (or 5) looks like a problem to the computer....

If you remove the shortest person and then pick a replacement who is the same height as the average of the other 27, he just blends in

 

I really enjoyed your explanation, just hilarious. Wondrous. It is actually a great way to (perhaps) ease the non-technical to formulate some idea of what is occurring.

 

When these batteries are created in the factory, all modules in the HV battery have chemicals etc from the same batch, same shift, same day, etc. So they are exquisitely balanced, perform together amazingly well. !0 years later, they have been heated up, cooled down, been discharged/charged hundreds of thousands of times. The original amperage capacity has diminished over time and use, may be down to 30%, 20%, 15% of original. A failure of one---essentially means the others will follow shortly. How could they not? If you catch them before failure, they can usually be reconditioned to 70% or so of original. Module (cell) shorts, however, are hard to predict (when a 7.5V module drops to 6V or so)

 

I find your explanations very clear, thank you for that.
I am very sorry to see that I made an unnecessary investment of over $ 1000 by purchasing a "Prolong Deluxe charger / discharger" and 7 modules at 6000mAh.

I discharged the pack up to 134V which normally corresponds to an individual voltage of 4.8V per module. Here in image, the results of the measurements. All modules purchased have a voltage greater than 7v. Others are less than 4.8V. There is a huge difference in capacity between cells.
Before replacing the modules, I had no P0A80 fault code although their capacity was low.

Tell me, if there is a possibility of combining the high capacity modules with the low capacity ones, to form balanced blocks?

Posted via the PriusChat mobile app.

 

Are those low voltage ones even usable?... Hoping for a response from a knowledgeable member.

Important missing information here is the capacity per module. That is a pretty similar across the 28 modules you'll be pulling codes.

Personally I would take this opportunity to upgrade all of the week sales based on discharge capacity.

 

If the capacities are not pretty similar across all the modules, you will be pulling codes. I think it will be worth several hundreds of dollars to get newish similar capacity modules.

 

You need to rethink about how the Prolong System works. The goal of the system is to 'help' the weak modules by cycling them. Strong modules don't need any help, right? The thought of a target discharge voltage corresponding to an average module voltage needs to thrown out the window.

After 15 years, your 28 new modules are now allover the place with regard to capacity. Some are still 6000, some 5000, 4000, 3000, 2000 or even 1000 or less. Which ones do you care most about improving? Probably not the 6000 or 5000 ones right?

When the Prolong starts discharging the modules:

1. All modules are participating in the discharge because they're in series. Whatever amount of current flows through one module also flows through all the others, whether it be charging or discharging.
2. Keeping #1 in mind, the module with the lowest capacity "empties" first. Then the next lowest and then the next lowest and so on.
3. Overall pack voltage is slowly decreasing the entire time. The vast majority of this decrease is due to the weak modules depleting and their voltages dropping more quickly than 'good' modules. These may be the 1000 and 2000mah capacity modules. A good module will plateau for a while at ~7.2 volts. The better the module, the longer the plateau will hold.
4. As the weaker modules deplete, you eventually reach the low voltage setpoint and the Prolong discharge stops. At this point, the weakest of the modules are fully depleted and the strongest modules have not been significantly affected and are likely to still be at the 7.2 volt plateau.

Now we start the Prolong charge cycle:

1. Again, all modules are charged at the same exact amperage.
2. Essentially, the module with the lowest capacity will be the one to reach full capacity first. Any module that reaches full capacity will just convert any additional charge current into heat while the remaining modules continue to charge.
3. Eventually, all modules will reach full capacity and the upper limit voltage of the charge will be reached and the charge can be stopped.

Now we start the next discharge cycle, except this time, Prolong recommends the low voltage limit be even lower than the first discharge. Why? Because now, the worst of the weak modules have been cycled and we can now try to also catch some of the next tier of "weak" modules. Now maybe we'll be able to get some of the 3000 capacity modules. The third cycle will be to an even lower final voltage. Maybe it will catch some of the 4000 capacity modules. And all during those second and third cycles, the modules from the first cycle are getting worked again.

Hopefully, by the time the three cycles are done, the worst of the weak modules have been worked the hardest, the semi-weak modules have been worked a moderate amount and the not-so weak modules have been worked a little. The strong modules? While the other modules are getting the workout of their lives, the strong modules are just chillin with a cold one, just along for the ride.

Always remember a grid charge system WILL NOT fix a FAILED module. There's no reliable cure for an internally failed module except module replacement with a good one.

 

Your time is money everyone's time is you figure out what you can afford The doctor Prius or the factory 1600 dollar pack for as long as they last it's just for me the way to go and once I've modified my brackets and I'm keeping the car after that if I ever do it again the battery change will be 14 minutes long because not near of the car has to come apart again . There's no replacement for new cells new electric cars don't get refurbed batteries they get new batteries and they cost but that's just part of it

SM-A715F ?

 

Time spent is usually important. If it’s not, keep working on it. Otherwise, if you’re planning on trying to keep car for five years more, get an OEM battery. For keeping it three years, get a Greentec with new cells. If planning on getting rid of it soon, get the cheapest solution you can find. Piece of mind with the OEM is a plus. But with a Gen 2 never knows when the Grim Reaper will arrive with either a massive inverter or other problem or a stolen or totaled car accident.

 

This makes no sense!
As the lower capacity cells are restored their capacity increases, so they take longer to discharge. There's no need to lower the discharge voltage to catch higher capacity modules, it just takes longer for the pack as a whole to reach that the discharge voltage. Excessive discharging just risks polarity reversal in one of the cells.

 

You don't say whether the pack has been charged yet? The whole pack needs to be charged to 224V, at which point all the modules should read 8.0V each. If any module is below 6.8V, then it has a shorted cell and needs to be replaced.
A module's open circuit voltage tells you nothing about capacity. That can only be measured by discharging, however matched capacities is not that important. When you charge a whole pack of modules together the voltages tend to balance out. The pack is only ever as strong as the weakest module.

 

Have you figured out that the explanation above DOES make sense and pretty much describes exactly how the Prolong System works?
Makes a lot more sense than asking if someone has charged their battery yet when the post is 2 and a half years old.......

You don't say whether the pack has been charged yet? The whole pack needs to be charged to 224V, at which point all the modules should read 8.0V each. If any module is below 6.8V, then it has a shorted cell and needs to be replaced.
A module's open circuit voltage tells you nothing about capacity. That can only be measured by discharging, however matched capacities is not that important. When you charge a whole pack of modules together the voltages tend to balance out. The pack is only ever as strong as the weakest module.

 

Just how not important is getting capacities reasonably well matched?
What do you consider to be an adequate range of capacities for a group of 28 modules assembled as a unit?

 

The Prolong System advocates excessive discharge and charging. My own testing has confirmed that discharging below 168V is of no benefit.

The capacity of the weakest module is more important than the range of capacities. It's that low capacity module which limits the capacity of the pack. Pairing weak and strong modules within a block might conceal a weak module from the Prius BMS, but it won't stop it failing.

 

My own testing has confirmed that discharging below 168V is of no benefit.
Although some may disagree, sounds like that pretty much settles that, doesn't it? Thank you for all your testing. Well done.

It's that low capacity module which limits the capacity of the pack.
Makes sense to me. Probably been mentioned a couple thousand times in various posts. Never hurts to throw it out there again.

Pairing weak and strong modules within a block might conceal a weak module from the Prius BMS, but it won't stop it failing.
Pairing weak and strong modules is a shi**y way to build a battery.

 

It would be good to see similar measurements from someone following the HA recommendations as a comparison. I wasn't in a position to risk loosing a module.

 

Last week I took my 2015 Prius V in for a 'smog check.' No sensor in the exhaust pipe, just a lot of ritual. The sensor came back with the dreaded P0A80 "Replace Hybrid/EV battery." First I tried to get Toyota to honor the California warranty, then Air Resources Board told me that the Prius V was NOT a Partial Zero Emission Vehicle PZEV, even though the smog test form says it is and is being tested as such....

I took it to a hybrid battery repair place. His sensor says Bank11 of the 14 banks has a problem. Okay.
Here's the rub. Because I let it sit too long the 12v battery died and needed replacing. When I did that I got a hybrid warning symbol and a Check Engine. My neighbor who fixes cars scanned it and then said, you just need to drive it for a hundred miles or so for that to reset itself. I took it to my mechanic who did an oil change, put on a couple of new tires. He said the same thing. At about 20 miles of driving -- no more warning lights. Mileage seemed a bit off. Okay I guess I have a problem.
However, this morning driving 30 miles to the battery repair I averaged 42 MPG (I have a roof rack). Normally, for years with this rack I'd average 39.5. I didn't do anything special. Also when the battery guy drove it into his garage it did it all on EV - silent. Whenever I'd start up the car in my drive way and pull out -- the gas engine always turns on.
I think if this were my Tesla and I didn't drive if for a while, the Tesla would do whatever it takes to keep the battery in good condition. The Prius clearly doesn't do that. .

 

I don't understand what your trying to say here but a low 12VDC battery will wreak havoc on the electronic sensors and trigger phantom problems and error codes. When the aux. battery was replaced, the car lost all of it historical setting and had to relearn everything - defaulted to factory base settings. Everything the cars telling you is suspect for the next few weeks until the ecu recalibrates everything. That's why you had to drive the car for 20-50 miles before the CEL would extinguish. As long as the problem doesn't reoccur after xx-number of restarts or miles, depending on the severity of the error - it'll clear itself.

Hope this helps...