Moving ahead!
I'm now monitoring the 20 block voltages during driving conditions. Also looking at pack voltage state of charge and current flow in and out of the pack.
I'm missing the pids and formulas for the temperature sensors in the pack.

I found two Banks further out than the other 18 those are my suspects.
I plan on opening the pack and begin voltage and load test on each individual module with my Keystone charge discharge balancer.

Looking for recommended parameters of rejuvenating balancing existing modules.

Upper current limits during charge?
maximum voltage at end of charge?
minimum voltage at end of discharge?
amount of currents during discharge?

number of Cycles charge-discharge?
1hrough 5 is my options on my device.

plan on running all modules independently hoping to find ones that don't respond well and replace them.
also thinking about pairing modules into blocks and running Cycles again to balance pairs.

Again any thoughts or ideas very much appreciated and considered. Thank you in advance for your time and patience.
Jim Fleck

 

ANY blocks outside a 0.2V range are suspect. Any "convergence" that appears to happen with continued use, i.e., the blocks appear to work better the longer a drive continues is a bad sign indicative of excessive self-discharge.

I recommend you record your drive data, export and post here.

What is a keystone blah blah blah?

(1) Varies. Should only be charged with NiMH capable charger
(2) Varies.
(3) 6.0V
(4) Varies but usually depends on equipment capability.
(5) Varies
(6) Complete and total waste of time. It doesn't work like this.

 

I will record some drive data before removing the pack from the Tahoe. Record and post hat data.

Oh yes, that thing I mentioned is a $60 device to charge/ discharge my modules. We will see if it can last long enough to finish the pack.

 

Please post link to device.

You're likely trying to drive a railroad spike with a tack hammer.

 

Good morning, this is my charger.

Keenstone Lipo Battery Charger/Discharger with Low Voltage Checker, 10A 100W AC/DC 1S-6S Digital Battery Balance Charger for Li-Po Li-Hv Li-Ion Li-Fe https://www.amazon.com/dp/B072V7PNJV/ref=cm_sw_r_cp_apap_wAHargfdSvyu1

I hope I can make it through the modules in my pack.

I have been very busy with family so I haven't got the pack out of the Tahoe yet. I still planning on getting data and post in it before I remove.

• 

1/4

(4) MATCHED TOYOTA PRIUS HYBRID BATTERY NIMH MODULES (2004-2009)

$120.00

$15.00Shipping
Jun 14Est. Delivery
Quantity :123456789101112
Buy another
Add to cart
Watch

Highlights

A seller you've bought from
Returns not accepted
38 sold

About this item

Condition
Used.
Quantity
38 sold
More than 10 available
Brand
Toyota
Manufacturer Part Number
hybrid battery module
eBay Item Number
192380733227
Item Ending
Jun 27, 2018, 03:44 PM PDT

Item description

Shipping, Returns & Payments

Ships from
Charlotte, North Carolina
Delivery to 97023
Est. Jun 14
From Charlotte, North Carolina
Returns
No returns, but backed CE…$3

 

5W discharge power means, you'll get about 700mA of discharge current.

Let's say your modules are actually "ok" and you'll get 4000mAh out of them...

4000/700 = 5.7 hrs to discharge one module.
charge at 6.5A = 1.1 hours of charging

6.8 hours to do one cycle on 1 module.

6.8 * 40 = 272 hours = 11.3 days.

3 cycles = 34 days
5 cycles = 57 days

tack hammer

 

Thank you for your input very helpful again.
I have the time to patiently do it right. Purchased a second car so I can have that Tahoe offline for 2 months if I need. Saving $4,000 is worth thetime and effort.

On the number of Cycles charge-discharge, I learned continue to do it until there's no longer an increase in capacity amp hour wise.
1) would that thinking be true?

Just to practice the formula you taught me.
If some modules have 6000 amphr. Capacitie:
6000/700= 8.5 hrs. to discharge one time.

I'm definitely committing to a long process. There's additional logistics as I'm sure you're aware of. Working a full-time job my son and I will be monitoring temperature and the process closely with the first few modules, at least until we settle into some kind of routine where we can start and stop as required to get maybe one module done per day.
Thinking about setting up a external fan to help reduce temperature as the battery and charger will be left in our shop on its own.

 

To avoid a repair, you bought another car, but it doesn't factor into your repair cost?

Again, you're assuming "patiently do it right" will actually yield acceptable results. You're assuming that these can be reconditioned when all evidence thus far indicates they can't.

Reconditioning fixes ONE thing - voltage depression - capacity lost due to short cycling compounded by heat. Reconditioning does NOTHING for batteries that sustain damage from use. All evidence shown thus far indicates the modules are DAMAGED when operated in a GM Hybrid due to aggressive over-use and bad battery management.

The good news is that most of your modules are going to be so bad, cycles will take far less time, so you'll probably know in a month or so that most if not all modules in the pack need to be replaced.

Alternatively, you could try:

https://hybridautomotive.com/collect...=6130817564710

or the value version:

https://hybridautomotive.com/collect...=6130818088998

And "recondition" your whole pack at one time over the course of a week.

Then, after the final charge, let it sit for 7 days and then spend a weekend using your discharger to discharge all 40 modules to measure their capacity.

You'd know in 2 weeks, but IMHO, you're just spending more money on an already costly repair.

I could totally be wrong. I hope I am. I hope you share your results either way as you will be the one exception of success.

 

I appreciate alternative perspectives I get from you and others on this site.

My buying a second car was going to happen anyway, I upgraded a 2-seat Volkswagen to a 7-passenger minivan. Plan on selling the Volkswagen, that I put a new clutch in, once the Tahoe comes back online.

with the dealership Diagnostics showing two packs with 11 volts I anticipate finding 2 to 4 bad modules within my pack. I am prepared to replace those with good used modules of 6000 milliamp capacity.

I did come across that prolong Deluxe but didn't look too hard after I saw the cost. I choose the cheap disposable junk intsead. We'll see how that works. Looking at it closer now as your recommendation I find no reviews and not much specific detail on how its intended to be used. A discharge ready car harness makes me think you discharge the pack while in the vehicle occasionally too deep discharge the pack and let the vehicle charge it. I know I have to disassemble my pack to get those bad modules replaced or my pack has no hope. If this device also charges the battery would not the heat be a problem with the pack assembled and all the modules interconnected. For reconditioning purposes I understand modules need to be isolated. And excessive heat is a guaranteed module killer.

Remove the pack for full disassembly
identify the bad modules.
recondition all the others
drive away as the Cinderella story of success!
Or
If my cheap device fails, I am left with a choice of spend the money on that quality charger you recommended or just buy a pack from Bumblebee Batteries and stick it in. ( they would actually be reconditioning my pack).

I am dreaming big and Aiming High with as much information as I can. But I understand this is a rarity for a do-it-yourselfer to go this far.
.

 

The dealership diagnostics is never complete. Most technicians don't even know how to interpret the non-explicit data. As an example, Toyota Techstream MAYBE detects bad blocks 50% of the time even with obvious failures. When rebuilding a 28 module pack, I replace between 5 and 6 modules ON AVERAGE because they don't meet my standards. The difference is I know how to spot the non-explicit data and identify on a gross level what kind of failure we're looking at... a handful of bad modules, or is it massive pack-wide damage.

I have tested Camry and Gen3 Prius packs that showed ZERO bad blocks and no failed cells, i.e., even when you measure the module voltages, you get ZERO indications of failed cells. These packs typically need more than 50% of their modules replaced for a mediocre DIY repair.

The first thing you should do is to use your discharger on the purchased modules. NOW.

The grid charger has been used on NiMH batteries for 6+ years. Mostly on Hondas.

It charges and discharges the pack as a whole to recondition it. The charger charges at 350mA for a very long period of time (24-30 hours) to balance all 240 cells at true 100% SoC. It also runs the battery cooling fan. The discharger discharges the entire pack to progressively lower voltages. You are reconditioning all modules at once. The process takes about 4-6 days to do 3 cycles.

If you get some data logged, we can get some insight into what you're looking at before you ever get started.

The best kind of logged data is constant current as it minimizes errors associated with timed reads... if you're taking a couple seconds to read and log 25 data points, you get time-related skew. If you're also dealing with variable current, it's almost impossible to correlate the data meaningfully.

Examples of "good":

1) Record "engine braking" going down a constant slope hill. Hopefully, the current will stay pretty consistent.

2) Record "constant load" situation, e.g., when the battery is at a higher state of charge and the ICE isn't running, maximize your electrical load, e.g., A/C, rear window defroster, lights, etc., and record this discharge. This tends to be nearly constant current and can really shed some light onto what's going on.