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Well, I guess my friend is in trouble for the moment. I ran 3 "modest" cycles with my genesis equipment. By modest, I discharged to 125, 110, 95V on discharge. Charges were to saturation level. 12hrs after completion the taps are at:
16.12
16.06
16.12
16.05
16.02
15.92
16.02
15.94
16.00
15.91

I'm a bit shy with the Genesis equipment because the discharge current is pretty high. I think it is of the order of 1.5A even when the battery gets down to 120V or so, but I'm just guessing from the brightness of the bulb. Seems to me that the discharger hammers the first reversed cells at around 1.5A.

Though not as awful as some that I've seen, I think this battery is going to continue to have problems.

Since it is not my car, I am trying to be very conservative. It is a lot easier to be more aggressive later than it is to explain how you ruined a friend's battery. I can always do more. In fact, he has taken delivery of the HybridAutomotive suite. That discharger is tapered and not nearly as unsettling to use, so may try to go deeper with his new equipment. At least HA sends specific instruction, so there is defense if it doesn't improve anything;)

Comments appreciated.
 

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Discussion Starter #82
If I had to produce an answer, it'd be that these cycles/parameters simply don't treat each cell similarly enough. For example, when you discharge down to the levels you list, you can have cells that don't discharge deeply and cells that discharge a lot more deeply or even reverse. And then, at the top with charging, you end up in a similar situation, where some cells overcharge more and end up with depressed voltages, and some cells don't charge fully, probably mostly because the discharge didn't 'free up enough active material' in the first place...

It's been a while since I've done similar full pack discharges and grid charges. But as I recall, I could easily end up with tap voltages that looked like that - and not think twice. But since I started doing tap-level ultra deep discharges (and before that cell-level with the stick discharge rig), the balance has been way closer.
 

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I test drove the car today. I was determined to use some max assist. I used max assist 6-7 times and the IMA or CE lights did not light. It may still not be well balanced but at least it seems to stay within bounds. The battery probably just has balance issues. If it had a high IR cell then the taps would seemingly go wonky and trip the warning lights with this level of assist. I don't know - I've never know. That is the reason I love my LTO.

My friend got delivery of his HybridAutomotive suite. We are going to install the harness while the IPU lid is off. I guess I'm going to advise him to drive the car until it starts recalibrating. That would seem to be a good warning level.
 

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Discussion Starter #84
....I used max assist 6-7 times and the IMA or CE lights did not light. It may still not be well balanced but at least it seems to stay within bounds....
Yeah, I'm not sure where to draw the line with these kinds of 'imbalance'...

As we speak I'm tackling a sort of novel idea based on something I saw after my last grid charge, which if true might explain to some extent the imbalance you see in the tap voltages you presented. I'm thinking that grid charge overcharge can fairly easily and quickly end up depressing voltages - so the cells (taps) that overcharge the most end up having voltages that are like 0.1, 0.2 volts lower than the rest.

I had at least two sticks (same tap) during my last grid charge that overcharged for something like 5 hours, compared to the others that didn't overcharge much at all. These two sticks ended up with a consistently lower voltage (you can see that in the tap voltages I presented some posts up). During subsequent use in the car, the voltage gap between this tap and the others tended to shrink the more I used the pack at very low charge states. That's consistent with the whole overcharge >> voltage depression >> deep discharge >> restoration idea . But you can only go so low in the car. So, I'm doing another deep discharge to see if the gap goes away. If it does I'll be pretty convinced of two things: 1) grid charge overcharge caused the depressed voltage, and 2) deep discharge can fix it.

But, these sticks (and two others) came from a different pack, so it might turn out that some more fundamental, material difference exists and is the source of the different voltage... We'll see. If it turns out to be true, though, it would push me even farther away from the whole grid charge regime. I haven't been a big proponent of grid charging for a while, but it may be even worse than I thought.
 

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Yeah, it is still a mystery after all these years. But we have tons of anecdotal evidence from many users that grid cycling works. You may be right on the phenom but I don't know how to deal with it. I guess we do know that a stick will have a slight voltage drop at the end of a charge when it is full. That is the delta V cut-off for chargers that we have talked about before. Maybe some stick have reached delta V and some not. Maybe the voltages can't be checked right after a saturation grid charge? Maybe one has to use the pack a bit, then check? I'm going to measure the taps again tomorrow after the use it had today.

I find it interesting but frustrating also :(
 

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Discussion Starter #86
Yeah, it is still a mystery after all these years. But we have tons of anecdotal evidence from many users that grid cycling works....
It works, but only to an extent, in a sort of gross way. Most people don't pay the amount of attention needed to really be able to tell how much grid charging works - or doesn't. It's hard enough just to tell how well the IMA is supposed to work in the first place.

....I guess we do know that a stick will have a slight voltage drop at the end of a charge when it is full. That is the delta V cut-off for chargers... Maybe some sticks have reached delta V and some not.
hmm, makes me wonder. I never really thought of the 'delta V' as being a potential precursor to this voltage depression I'm postulating exists. Maybe to some extent it's one and the same thing -- that if you keep overcharging you will see voltage drop, and it actually ends up sticking... If it does I never noticed it, but then, I don't think I would have - because all the (my) cells are usually being overcharged similarly... The idea that you'd see different voltages based on whether cells have delta V'd or not, that makes sense.

Maybe the voltages can't be checked right after a saturation grid charge? Maybe one has to use the pack a bit, then check? I'm going to measure the taps again tomorrow after the use it had today.
Yeah, if you need measurements that better capture the 'true' voltage of your taps - that characterize them - then you'd have to drive, let the pack rest a bit, and then take measurements. If a gap/variation persists, then you know it's more real. Personally, I like to take tap voltage measurements at pos recal and at near empty: If the taps are close, especially at near empty, you're good to go...
 

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Well, I've been keeping records, so I'm prepared to do the taps again tomorrow morning after some use and overnight rest. Maybe we will learn something or maybe not ;)

Do you know what the delta V is supposed to be for a cell?

There is also another complication. Since taps look at 12 cells, maybe some cells have suffered delta V and others not. It makes my head spin.

I guess that if someone charged a very long enough, say 40 or 50 hours, then every cell has achieved delta V, whereas if not that long, the taps may fake the operator as one cell achieves delta V while another cell is still rising - resulting in a "stable" tap voltage. It makes my head spin.

I've got a bunch of data from my stick station work, but it is all hand written so big job to post it. I think I will at least revisit it.
 

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Discussion Starter #88
Well, I've been keeping records, so I'm prepared to do the taps again tomorrow morning after some use and overnight rest. Maybe we will learn something or maybe not ;)
If you see variation that's more or less the same pattern as what you posted earlier, mainly the three 15.X ones are still low relative to the others, I'd see that as...decent evidence of my overcharge idea - that those three taps overcharged the most, voltage was depressed, and they're not likely to get back in line without some kind of deep discharging...

But looking at those voltages and when you measured, they all seem lower than I'm used to seeing. The highest was 16.12, which is only 1.34V per cell. After a full charge and 12 hours rest, I wouldn't expect voltage to fall that far. Maybe to 1.37V, but 1.34V - I haven't seen that. And that's the highest voltage; 15.92V would be 1.327V per cell... Not really sure what to make of it. My 'bad' cells usually stay higher than the rest, longer, like above 1.40V over the first 24 hours or so. The 'good' ones - pretty sure they fall below 1.40V but not below 1.37V... It's a weird thing with these cells, haven't figured it out...

Do you know what the delta V is supposed to be for a cell?
Only the common recommendations - 4mV per cell. I haven't used delta V in ages, and I never had good enough equipment or the insight to actually measure it when I did use delta V...

There is also another complication. Since taps look at 12 cells, maybe some cells have suffered delta V and others not... if not that long, the taps may fake the operator as one cell achieves delta V while another cell is still rising - resulting in a "stable" tap voltage. It makes my head spin.
Yeah, recognizing when a true full is achieved is trickier than I think we make it out to be. And then, I think there's this added... risk, where overcharging might be more deleterious than we realize. Personally, I've been leaning toward discharge and bottom balancing being the way to go, rather than grid charge and top balancing.
 

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OK, this morning the taps are closer. The tap values seem to be converging a bit.

15.62
15.57
15.63
15.58
15.58
15.49
15.56
15.50
15.57
15.48

At the 12hr resting point after cycling the spread was .21V. Now the spread, after use at SOC of about 60%, is .15V. This measured with a high quality Fluke meter.

I think this battery bears watching for the first recal, then some truly deep cycles with the HybridAutomotive discharge??
 

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Discussion Starter #90
I'm rearranging your data to help me see it better; "deviation" is difference between measured values and the average...

initial, 12h after GC: 16.12, 06, 12, 05, 02, 92, 02, 94, 00, 91, AVG=16.02
deviation init: 10, 04, 10, 00, -10, 00, -08, -02, -11
deviation latr: 06, 01, 07, 02, -07, 00, -06, 01, -08
later, after usage: 15.62, 57, 63, 58, 58, 49, 56, 50, 57, 48, AVG=15.56

All-in-all, I would have expected the 'spread' to shrink a little, as it did. All of the deviations shrank by about '3', or 30mV. For example, the first tap went from a deviation of '10' (100mV) to '06' (60mV), a difference of '04' (40mV). The next tap went from 40mV to 10mV, a difference of 30mV; the next 100mV to 70mV, a difference of 30mV. And so on. So, the deviations all changed in magnitude about the same amount. But, the overall pattern remains the same, where the same taps remain high and the same taps remain low... I'd call this consistent with what I was saying about overcharge, voltage depression, etc.

I suspect that general pattern won't change, or rather, there's something material (i.e. chemical imbalance, 'active material imbalance', whatever kind of imbalance among the actual stuff in the cells) causing the difference, and that difference will play-out over usage. I'm pretty sure the voltage differences reflect a fairly direct relationship to capacity - that the low voltage taps, for instance, actually do have a smaller capacity in their currently conditioned state. That can manifest in both raw amp-hour output, but more importantly, in power output. Not sure of the Ah amount, I've checked that before but I forget. It's probably in the 100s of mAh, like -200 mAh, -300 mAh, etc. I don't really have a strong grasp of how this all can "play-out." I think there are various trajectories that can happen, depending on how the pack ends up being used.

In the simplest conceptualization, I just see the imbalance as affecting the cells differently over time and usage, where I think the least capacity cells/taps end up deteriorating sooner rather than later...

Anyway, I personally wouldn't wait for a neg recal to take action. I know this isn't your pack, so, I don't know. Were it my pack I'd be doing a tap level ultra-deep discharge, but I realize that's a process people aren't keen to take on... IF, for some strange reason, you and your buddy felt like contributing to my knowledge base, you'd do a tap level UDD, a full but not-too-long grid charge, and then report back tap voltages. If you did this and we saw a) higher voltages and, b) more even voltages, it'd be very strong evidence of the value of tap-level UDD, in my opinion...
 

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I'll talk with him about the UDD when I see him. Since he has invested all that money in the HybridAutomotive suite, he may want to try that first. I have a disassembled pack which I rebuilt myself and which didn't perform all that well. If I can find time, still tinkering with my LTO conversion, I might try the UDD on that pack of mine. The sticks in that pack were pretty decent, but they came from different Insight sources and of course have different histories.

I also have some sticks which I think are strong performers, more recently acquired, which I could use in the test battery and that has already crossed my mind. I'm still interested in the "science" if we can call it that, but I'm trying to rid myself of the NiMH headache. If I can build a decent pack with "severe" selection, I might just give it to my friend to get the sticks off my property;)
 

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How about this plan. I have about 28-30 quite good sticks either in the pack I discussed just above, or on the shelf. They have all been stored and discharging for about a year. I could subject them all to UDD according to your method. I could then do a calibrated charge/discharge for capacity measurement, and then use a calibrated charge for measurement of self discharge over time. I could select the 20 "best" sticks and build a battery. What you think?
 

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Discussion Starter #93 (Edited)
^ I think it's probably too much work with too little potential pay off. The 'beauty' of trying a tap UDD on your buddy's pack was that we've already done one method (Genesis cycling), taken voltage measurements, hashed those over, and developed a hypothesis. The only thing left would be the tap UDD and some voltage tap measurements. I totally understand though that doing that to your buddy's pack is inconvenient, etc., that's OK.

With your stored sticks, they've already been self discharging for a year, which complicates things a bit. We have no baseline. Etc. I don't want to see you get sucked into some NiMH putzing that has dubious payoffs, especially now that you're into LTO.

On the other hand, you have sticks 'laying around' that I'm sure you want to get rid of, but in their current form it's hard to know what to do with them. I'm kind of in the same boat. I have one pack, a rebuild, that I've established as working great. I have an older rebuild that didn't do as well as I had hoped, from like 3 years ago, that I just rebuilt again with my 'new methods'. That's looking really good, so now I'll be able to, well, probably just set it aside knowing it works... The good thing with this rebuilt rebuild is that I recorded quite a bit of data when I took it out of the car, so I know 'how it looked' before, and will be able to compare to what it looks like now, after these 'new' methods. I'll be able to tell pretty well how much the new methods worked (or not), basically...

So anyway, I would suggest you might do this:

1) Take your worst sticks and assemble a pack.
2) Grid charge them maybe for about 4 hours, just enough to get them off the self-discharged floor.
3) Do the tap UDD - short 5 taps at a time, taking each tap down to about 1V or less (this will take quite a while, like a week for each set of 5).
4) Do a full but not too long grid charge.

After that I'm not sure what you'd do - you'd have to have a car to put the pack in and try it out, and then measure voltage taps. I think the two basic metrics we'd be looking for is 1) Full assist at low charge state - Can you get about 80 amps at say 40% charge state? and, 2) Are the voltage tap measurements even? To my eye those would be pretty telling metrics, that if both are true, the recondition is likely to be successful...

One problem with the above, though, is that part of my 'new methods' hinge on the idea that most OEM battery management isn't good. In a nut shell, I've recorded IMA data for trips over the past couple years that show that OEM management is inefficient, and I think that inefficiency might reflect, be the cause of, be related to, deterioration. When I purposely use the pack at low charge states, efficiency goes way up. And I guess the corollary to this is that indicators of 'pack slippage', of deterioration, grinds to a halt. I just don't see the pack slipping, relapsing, the reconditioning holds...

I don't have a good handle on the extent to which my rebuild success stems from the initial reconditioning or the low charge state usage. In general the two go hand in hand - you can't get low charge state usage without the reconditioning, yet it seems like the reconditioning is less likely to hold unless you do low charge state usage...

Anyway, I'll leave it at that for now.

Oh, one more thing. I'm also not into NiMH testing as much as I used to be. Doing this rebuilt rebuild, for instance, is just kind of a side venture - the sticks were gathering dust, taking up space in my house. I'd have to say that's probably the number one reason I'm doing anything with them at all. I like to think about NiMH packs - as long as it fits into to everything else I'm doing. If I can drive and watch some OBDIIC&C IMA info and glean some insights into battery management and NiMH, fine. If I can take some voltage tap measurements while I got the IMA compartment open, fine. But I have no patience for the strictly scientific-like data gathering and testing that I once did. I spent enough of my life doing that already. I think you can probably relate...
 

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Yes, I can relate. I think I ran out of patience before you did ;)

I do need to clear out the sticks, like you. I particularly need to build as good a pack as I can with the best of the sticks, and I think I now have enough good sticks to build a good pack.

I'll contemplate your idea of building a pack with sticks from the second shelf. Winter is coming on and I will have some time in my heated garage.
 

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Discussion Starter #95
I mentioned above some posts that I was working with this rebuilt rebuild and 'testing' an idea about overcharge and voltage depression (it's post 84 above). Some unexpected stuff happened and I'm kind of trying to sort it all out at the moment...

In a nut shell, I was thinking that a sort of deep discharge would get rid of voltage depression on tap 9, that I was thinking was caused by overcharging. I started with a light bulb discharge - 11 watt bulb - but switched to tap level shorts after some hours because one of the taps was already really low. I wasn't totally consistent with my tap discharges - I was thinking that it didn't really matter. I think I was wrong. I went longer with some taps, for instance... And I was thinking that I probably wouldn't need to do a full grid charge - I only charged for a few hours. It was pretty cold, 42F when I started the grid charge. I didn't think that'd make much difference...

But, somewhere in this process, I've totally screwed up my pack! The good thing is that, yeah, it looks like 'voltage depression' on tap 9 is gone - the voltage is looking pretty much in line with most of the taps, it's at least not a low outlier as it was before.

The bad thing is that now I've got a nearly empty cell on Tap 1 when the pack should be at about 40% true charge state!

This is really quite... interesting, yes, but like I said, totally unexpected, and it's not like I wanted to spend more time with this. It appears that one or more of a few things can really mess up a recondition/balancing operation:

1) Cool temps might make a big difference. I know temps matter, but I wouldn't have thought I'd have a problem with this previously very well working pack.

2) Uneven deep discharge might matter. This is really a puzzler. It almost seems like deep (really super deep) discharge might break down the low voltage 'structure/composition' of the electrode/s, for lack of better terminology, and it can take varying amounts of not insignificant amounts of charge (current) to get the cells, not necessarily "going," but get that low voltage structure rebuilt... I was thinking that something like this might have been the reason Tap 9 got overcharged so much in the first place, relative to the others. Not too sure...

3) IF you have an uneven deep discharge, it would become essential to have a full, balancing grid charge. Even if you have an even deep discharge, perhaps it's still essential that you do a full grid charge... This is really weird. After my short charge, I drove and the pack seemed fine. It wasn't until the next day, today, that the problem became apparent.

4) Based on my tap voltage measurements and what I saw driving yesterday, it almost seems like a single cell self discharged very very fast, like over night, from about 55% to near empty. That's bizarre. It's likely, possible, that something in my process ended up mucking up a single cell (or more - the other tap voltages aren't perfectly balanced either)...

Anyway, thought I should spill some ink on this, if only to help sort this out for myself. This last idea - the weird self discharge - is really a critical thing. I just can't believe that anything I did - the deep discharging, the partial grid charge - actually resulted in a single cell that wasn't charged much to begin with; it really does seem like something in this process caused super fast self discharge - I don't know, like some nickel got re-arranged and ended up shorting a cell... Discharging below 0.25V is supposed to create a galvanic reaction where nickel is restored to the collector; it's possible and likely that a single cell got that low, for sure, could it be possible for this activity to result in an unusual orientation that results in fast self discharge?? Maybe without a full charge, 'stuff' doesn't get distributed evenly, smoothly, etc?...

Very weird...

Keep in mind that most of this is relevant to others doing just grid charges and full pack deep discharges, especially the not-very-low-voltage variety. At minimum, it seems very easy to end up with not so balanced cells at the bottom, after a discharge process, and then having to make up for it at the top - where overcharging can then become an issue. And it seems possible that anything short of a complete process might cause some 'anomalous artifacts' - like my stray nickel crystals and fast self discharge idea...

Not sure where I want to go from here. But it seems clear what I should do - an entire Tap UDD, ultra-deep discharge, again, and then do a full grid charge, again. This is a slow process, especially with cells at about 40% charge state. A real bummer - I'll be putzing about with this for maybe another couple weeks... If I tried to do just a grid charge, I'd have to overcharge most cells by a lot to get the whole pack balanced; if most cells are at 40% and at least 1 is empty, I'd have to overcharge most cells by 0.4 X 6200 = 2480mAh in order to get this pack balanced, at minimum... And then I end up back where I started. Doesn't sound attractive...
 

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Discussion Starter #96 (Edited)
^ Despite the unattractiveness of that last option above, I decided to move in that direction. For now I just charged in-car and let the pack pos recal, and took some tap voltage measurements. I'll probably grid charge at least some...

Figured I take this opportunity to show you some more data that illustrates just how difficult it is to get a good read on pack balance by reading voltage taps. As I mentioned above, based on BCM/MCM behavior I was seeing in the car when I drove yesterday, as well as tap voltages, it's pretty certain that at least 1 cell in Tap 1 was near empty, while the rest were around 40%. I've seen this behavior before, it's a little weird: the BCM or MCM throttles assist very aggressively, I think in response to a tap's voltage dropping fast, presumably because a cell is near empty and its voltage is dropping rapidly. I'm not sure why or what the difference is with this versus getting a neg recal, though; normally we all assume you get a neg recal when 'a cell drops out'. Apparently that's not always the case. Suffice it to say that I'm like 99% sure I had a near empty cell after yesterday's drive.

So today I just let the pack charge normally while driving, to in-car full (i.e. pos recal). I took voltage tap measurements before and after this trip. Here they are, before and after:

15.40,76,79,82,80,75,70,75,75,80, avg. of taps 2-9 = 15.77V
16.59
,65,67,69,68,64,63,63,67,70, avg. of taps 2-9 = 16.66V

So, the tap with an empty cell at the start, in bold, is clearly lower, but look at just how little lower it is after the in-car charge to pos recal. The average voltage of the other cells is about 16.66V, so Tap 1's voltage is 'only' 0.07V, or 70mV, lower than those... Yet, one cell in this tap is likely ~40% less charged than all the other cells. Huge charge state difference, very little indication of it in the voltage tap readings...

You can see, though, that at the bottom end the gap was more noticeable, which suggests that reading voltage taps can be more telling at this extreme...

For reference's sake, here's some tap voltages I posted a couple weeks ago, of this pack but before I did this failed deep discharge and partial grid charge:

16.04,04,04,07,04,03,04,04, 15.96, 00

So here you can see that most of the unevenness we see today is soley due to my botched deep discharge/partial grid charge operation -- due to one or more of reasons 1-4 that I listed in the post above.
 

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Discussion Starter #97 (Edited)
I stumbled upon some old work I did that I never really followed through with. A few years ago I did a sequence of charges and discharges on some Insight cells to get a sense of what charge state such and such voltage would bring the cells to. Figured I post the results and a few of the graphs here. It's not super scientific, but the methods, the sequence, etc. was pretty good, consistent.

After normalizing the 2 cells with a few cycles, I charged with a constant current charge up to a threshold voltage, at 3A, then let the charger implement its constant voltage algorithm at the threshold voltage - which simply holds the voltage while tapering current until it reaches 300mA, at which point the charge is over. Then, I discharged down to 1.1V, also at 3A. I'm working with 2 cells, so the voltage is actually 2 X 1.1V, for instance. But I'm able to monitor individual cells, and that's what the few graphs below show. The last row is a charge with a 2mV delta V.

Here are the results:
threshold voltage, capacity charged (mAh), capacity discharged
1.32V, 0698, 0672
1.36V, 1810, 1770
1.40V, 4300, 4346
1.44V, 5166, 5217
1.48V, 5720, 5640
1.52V, 6864, 5915
2mVdV,6496, 5832


Here are graphs for a few of the charge discharge pairs.
To 1.36V
83562

To 1.40V
83565

To 1.44V
83566

To 1.48V
83564
 

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Discussion Starter #98 (Edited)
Here's a nifty little dataset that might help battery-putzers wrangle with self discharge. Or, consistent with data I've posted before, might show you just how difficult it is to identify doomed packs based on tap voltages, or even on stick voltages. Tiny voltage differences can mean a pack that won't work - a single aberrant, high self discharge cell that will result in an IMA light sooner rather than later... Take a look at the data below and you'll see what I mean.

These are data based on the remaining sticks from a rebuilt rebuild I was working on. The other few sticks not in this set also had single high self discharge cells. All the sticks were more or less conditioned, balanced, and left at about 73% charge state 33 days ago. Most of the cells still should be at around 70% charge state. The red-ish highlighted cells are ones with high self discharge (HSD) - they likely have very little charge left in them. Most of the sticks with these cells won't work, they'll cause any pack they're in to fail. Stick 50 for sure, probably stick 37, and 45 and 41 will cause problems eventually. The yellow highlighted cells are questionable. Sticks 71 to 74 at the bottom come from a different pack, which is why voltages are slightly different. All the sticks are 2007 Civics, though.

You can see how stick voltages are almost all the same - except for those with the high self discharge cells. The HSD cells lower voltage only by about 100mV (0.1V). It's easy to spot the HSD cells among these sticks, I think, because these sticks are reconditioned; I think unreconditioned cruddy sticks and cells would have a wider voltage range and so, identifying HSD cells among them would be more difficult...

1.318V is the equilibrium voltage for Civic cells (possibly Insight as well), so I'm thinking that self discharge that drops cell voltage below that value are at least suspect. Not really sure, but it's probably a decent guess.

83652
 

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That shows the importance of cell level work which is even more time consuming and tricky than stick level!!

I def need to build my semi automated stick tester.. It's been discussed lots of times..
I even have a schematic somewhere...
 

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Yeah, basically shows that stick level efforts are uncertain at best, and probably futile given that one would pick 20 sticks from a list, basted on stick level parameters alone. You may have touched on the reason folks have such poor success with rebuilding efforts.

I have done a lot of cell level qualification based of heavy test currents and high indicated internal resistance(IR), but even that did not insure good packs. Looks like I may have overlooked the importance of self discharge(SD). One has to be impressed with how uniformly "good" cells are in their SD rates.

Of the three major parameters, IR, self discharge, and capacity what is your ranking of defect likelihood?

I'm a bit confused by the term "equilibrium voltage." How do you define this term?
 
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