How I Recondition Cells

So I just got my Chinese Battery Volt meter Resistance tester, I like it, came with 4 wire leads, two sets, probes, and alligator.

LeTkingok 4 Line YR1035 Battery Internal Resistance Test Meter-- High Precision /Battery Voltage Tester/Digital Battery Analyzer (Set E)
Brand: T-king
$72.99 in stock amazon quick ship and delivery 12 left lol :O

This is the newly reconditioned rebalanced pack of Prius Modules I made for my Honda Insight

docs.google.com/spreadsheets/d/e/2PACX-1vTl4JLzOw1nsapjoGlqDtTIHd9UMrgPD4_DH5R04nQcvznddF76PXzNqxjqzjgD3e-2jbhuPXRsd8IO/pubhtml

Someone testing the cheap meter

 

Yep, you have to do them one at a time.
It's possible to shortcut things, toss some modules in from a wreck and hope for the best, just ,make sure all the modules have been discharged to some target voltage like 7.1 volts first using some load and a meter. Could be a brake light bulb with alligator clips.

String Charging versus Bank Charging (for some reason string charging got morphed into the term GRID charging by the people that started making string chargers about 13 years ago, even though bank and string both use THE POWER GRID to operate).

Bank charging is what I used to sell when I teamed up with a company that made a truly excellent balancer. I was the tester for their product and after about 2 years of getting them to alter the product and get it to work, I sold many of the prototypes and they worked great. Then, when they went into production, they decided to POT all of the units in China (mine were all made in Chicago), without testing, and the Consumer Product people made them recall them all when they burnt several vehicles and garages down. Idiots.

Fortunately, they sent me my 100k in product on spec and I never had to pay for it, cause they didnt refund anyone after bankruptcy. I have a ton of them lol.

In any case, BANK charging would require running 28 wires (not really it can be done with 15) to the battery pack and using 28 chargers connected to the power grid to top off and peak the modules occasionally to extend their life. The BALANCER they made allowed us to get rid of the expensive bank charging scheme as it shuttled power around to balance the packs and could move 15 amps at a time, worked great, until they potted it to HIDE their trade secrets lol.

 

Heres another sheet that has the readings on 28 modules in the pack I previously cherry picked from to make the insight pack

docs.google.com/spreadsheets/d/e/2PACX-1vRw_RS2C5mJW7vm3Ktmap1VqMz8CDyuB6ShLssQVBApHlWH4KwPxt3eeQmSvQA-BGKwqt04MkQ7g1cl/pubhtml

If I had that chinese meter when I started, I could have saved days weeks, by cherry picking all the ones that are LESS than 7 milliohms and sticking to them for testing, at least thats how it seems when you look at the two sheets, last two I posted here.

I chose based on best capacity, and they all ended up less than 7 when tested later

 

Here is an Easter Egg for that cheap china meter, you can add serial port to it.

https://secondlifestorage.com/index.php?threads/yr1035-enabling-serial-port-to-read-data.10603/


and more info on the meter

 

2001 Prius Powered Insight IMA light | Honda Insight Forum

 

I elected to go further in testing my newly rebuilt Honda Insight pack, that uses Prius Modules.

One concern I had was any modules that may have a high level of self discharge, that could throw things awry if the car was parked an extended period, throwing the pack out of balance, so I decided to test for that.

In developing that test, I added new items to do more testing.

I have 20 modules to test over a 7 day period, (the testing began a week ago, one more week to go).

It has provided a STUNNING development in the form of a 19.% percent additional capacity in a module I deemed 100%, placing that module at 6.457 amp hour capacity when tested at a 6.5 amp load (1C) to a cut off of 6 volts.

6.457 is 100% of the original capacity, and this in a 2005 module that has a lot of miles on it.

This is the first of 20 to be tested, all using a new charging algo.

This algo was developed to prevent heating gassing swelling and venting, and it worked (on previously proven modules that had already been cycled to a restored condition). A modified version of this same algo should probably be adopted in the recycling charge discharge of unknown modules.

Step 1- Discharge to 6 volts at a 5 amp load
Then, repeat at a 2.5 amp load
Then, a 1.6 amp load
Then, a 0.8 amp load
Then, a 0.4 amp load
Then a 0.2 amp load
Then a 0.1 amp load but this time TO 5.9 VOLTS.

Step 2 - Charge at 0.1 amps until voltage reads greater than 7.1 volts and less than 7.2

Step 3 - Charge at 3 amps and insert 6 amp hours into the module (approx 2 hours, lower this charge time on unproven modules)

Step 4 - Charge at 1 amp until EOC is reached/detected by a lowering voltage, this typically means inserting 2.5 amp hours on a GOOD module.(approx 2.5 hours, on unproven modules where step 3 is lower in time this may be higher in time)

Step 5 - Discharge at 6.5 amps to 6 volts and record that capacity. (I did this a week later to compare to old readings looking for excess self drain over time)

Step 7 - Charge at 6.5 amps inserting 3 amp hours

Step 8 - Continue the charge at 2 amps until eoc is reached.

Step 9 - Discharge at 6.5 amps to 6 volts and record the capacity. This is where I got 6.5 amp hours an almost 20% increase over my previous best on this module.

 

Thanks John, yes so far its pretty interesting, here is the next module, it tracks so well you almost cant see the first module test
Also interesting is I only drain to 6 volts but they fall off so fast at 6 volts the tester cant shut down the load fast enough, hence the cliff knife edge end of charge
Red 6.457 and Green 6.415 ah capacity
I have all 20 on a test schedule which is completing over the next 6 days so new results will show up every 8 to 12 hours here.
The tester defaulted to a wonky scale for ah on bottom of graph, i will see if i can adjust that to something readable

 

Why I don't take them down below 1 volt per cell
PANASONIC SAYS DO NOT DO IT
Also, the industry says do not do it.
That why I do not do it, others can if they so desire, I tried it, I saw zero improvement to doing it two weeks ago after seeing people were doing it here.

Also, above i refer to 6.5 amps for 3Ah followed by 2 amps for 6 Ah, my charger allows me to set limits, these were my limits, the module took LESS than these limits
It took all 3Ah cause the module was empty, during the second charge at 2 amps the limit is 6 it took less. The TOTAL allowed is 9, it took between 8 and 8.15 on the two I did the test on that returned 100% capacity. I allowed for more Ah in case it needed to "slow cook" end of charge to reach a true end of charge. So for those that attempt this without a programmable charger, watch at 8 Ah TOTAL input for EOC.

 

"Swelling occurs when the high voltage cutoff is reached, but I don't have time to sit and watch the cells to see if they start changing in appearance."
No, swelling occurs when you feed in more AMPS than can be dissipated by the almost fully charged module.
Adjust amps down near end of charge to what the module can dissipate and it wont swell.

If you feed in 10 AMPS you cant just TURN IT DOWN you have to wait for all the excess higher charge voltage that was created to burn off, hence, bulk charge at a LOWER amp and LOWER voltage and you can continue the end of charge at an even lower amperage and no swelling.

Proven over the past week on these 20 cells.

The recipe is above

P.S. You can easily make a swell sensor to disconnect the charger, but why introduce the swelling pressure and heat in the first place, to make one you need a switch to detect the swell, then pry the module slightly on one of the top ends and insert the switch, set to open or close when the desired swelling is reached, connected to a control board with a relay to kill the charger input.

You can probably even find a state of the art pressure sensor and react to the change in that sensor shoved into the crack in the module you make by slightly prying it open

Like this maybe



Or, even cooler



TOYOTA SHOULD HAVE USED THEM TO DETECT SWELL AND GENERATE A CODE LOL

 

Once I get this insight taken care of, I have a "Wonderfully Dangerous Experiment" to post

Potassium Hydroxide is an odorless, white or slightly yellow, flakey or lumpy solid which is often in a water solution. It is used in making soap, as an electrolyte in alkaline batteries and in electroplating, lithography, and paint and varnish removers. Liquid drain cleaners contain 25 to 36% of Potassium Hydroxide.

 

There are a number of variables here that MAY be adding to these modules performance,
1- The weird low amp repeated discharge to 6 volts
2- The multi stage charge to a full end of charge that may help balance and "bring up" an under performing cell
3- Keeping the amps low to avoid/minimize heat swell venting and pressure
4- Letting them sit a week at full charge in a highly gaseous state, allowing that gas to permeate in the common atmosphere rail unique to the prius module and possibly rejuvenate or chemically balance other cells.

Number 4 is the main reason I tell people to drop those honda batteries and go to prius, no common atmosphere rail in the honda design.

 

So far I am 3 for 3

 

My fourth module, number 7 (I do all the odds one on one side then the evens, so wire swapping and accidental reverse polarity hook ups are avoided) anyhow, module 7, as I had noted previously and prior to exposing it to the new algo / one week drain test, may have within it an under-performing cell,

The algo did extend the capacity, from 4.64 Ah @ 6.5 amp ( 1c ) load to 5.72 to 5.89 Ah under 3 more tests. However, it not only failed to hit full capacity, it showed an aberrant behavior at end of discharge. Where other modules exhibited a nice long slope, module 7 just stopped and dropped like a rock, and I think I not only know why, but can now say that this behavior CAN / MAY be interpreted to mean one particular diagnostic when viewed as a whole across the entire discharge graph.

If you examine the graphs below you can see than, until end of discharge, the performance is 100%. Then, it drops, AS IF IT RAN OUT OF GAS, and it did.

Firstly, the tester is set to cut off at 6 volts, had it not been so configured, we would have seen a continued discharge of the module at a voltage less than 6 volts, as the other 5 cells that DID NOT RUN OUT OF GAS continued to perform.

What do I mean ran out of gas ?
It ran out of WATER. It is obvious from the graph and the math.

The NIMH runs at 7.2 volts, after which, it slopes downward.

At 7.195 volts (on module 7) we see the knife edge begin and the drop to 6 volts and shutdown of the recorder.

7.195 volts divided by 5 (the remaining 5 good working cells in module 7 ) is 5.99 volts which explains why the sharp drop to under 6 volts and recorder shutdown. One of the cells had to have a catastrophic sudden onset loss of fuel for this to occur as depicted in the graphs (had the load been less than that 1C, we would have seen more or a slope but still sharper than the normal gradual slope to eoc, the higher 1C drain could not be sustained by the lack of water hence the sharp drop).

THERE WAS ALSO ONE OTHER INDICATOR, this showed up on end of charge, via the voltage after 4 minutes. The three good modules that DRAINED settled at 7.01, whereas the module that ran out of water under a 1C load, settled much higher at 7.45 volts, why ?
Because it has plenty of power left, and water to run it, but not at any appreciable load factor.

 

Thanks for the invite John, hectic now, hay season, I will hit you up

 

Here's a good book, has a good section on NIMH chemistry operation and charging,

It's about 55 cents a page, but there's 4,538 pages lol

Encyclopedia of Electrochemical Power Sources - 1st Edition

HERE, I SAVED YOU 3,000 BUCKS
vdoc.pub/documents/encyclopedia-of-electrochemical-power-sources-6ua7pkcu90e0