Can you de-bloat XUBA 280aH Lifepo4 cell?

[heirloom hamlet]

The question says it all.

I'm soooo done with following all these top balance suggestions. The cells were great. They didn't need this forced voltage garbage and neither did I.

Now I need to try and fix this overcharged cell or figure a way to get XUBA to ship me 1 or 2. What a shame.

 

[Luthj]

How bad is the bloating? Did the safety valve blow? Typically significant expansion/swelling is electrolyte breakdown. Mild swelling is caused by normal cycling.

If the cell shows normal voltage, resistance, and capacity, it may be possible to continue using it. Obviously it depends on your application and C rates.

 

[heirloom hamlet]

How bad is the bloating? Did the safety valve blow? Typically significant expansion/swelling is electrolyte breakdown. Mild swelling is caused by normal cycling.

If the cell shows normal voltage, resistance, and capacity, it may be possible to continue using it. Obviously it depends on your application and C rates.

Pretty bad, not normal, but also not the worst I've seen pics of.
Did someone from the forums series charge up instructions, preluding a parallel balance. This is what I got. The voltage on the battery main negative cell shot up to 4.(friggin)8, and the damage was done.
I quickly got it under a load and it right away plummeted and is playing nice with the rest of the pack. All stabilized at 3.333. I don't know about resistance and capacity, but the voltage is normal.

 

[heirloom hamlet]

It was all a few minute experience.

 

[Luthj]

Ouch... I personally would not use that cell for anything important.

 

[heirloom hamlet]

Ouch... I personally would not use that cell for anything important.

What's important? What could transpire?

 

[Luthj]

There could be physical damage to the layered anode/cathode sandwich. Voids, etc. I am not familiar with the construction of those cells, but if the separator fails, the cell could short circuit internally. Either slowly, or quickly. A rapid internal short results in the cell heating up and eventually venting its electrolyte. Electrolyte is not pleasant stuff to deal with and is flammable.

You appear to have that pack wired in a 1P configuration, so it shouldn't take out the other cells if you have a proper BMS.

In an over voltage situation the electrolyte between the anode/cathode is broken down into byproducts, including gases. This tries to push the layers of the sandwich apart. If I was just dicking around with a test bed in a safe non-enclosed location, I might be temped to vent the case with a needle, compress the cell flat, and seal it back up. Or maybe just capacity test the cell and let it run. But this is very risky, and not something that should be done with a pack that will see any kind of reliable service.

What peak voltage did the cell see during this event?

 

[GMB]

That is unfortunate. Sorry for your loss.

Can you describe your top balance procedure you followed? The info would be nice to have so other members don't have batteries end up like this.

 

[mrdavvv]

Lately ive seen a lot of people ruining their cells, maybe we should start adding more disclaimers in the top balance guide's, mentioning the possible complications, consequences and examples of failures.

For OP, LIFEPO4 its a very safe chemistry but still risky to use cells in that condition, in my opinion its not worth it any remaining life / capacity for the risk involved.

 

[sremick]

Lately ive seen a lot of people ruining their cells, maybe we should start adding more disclaimers in the top balance guide's

I think part of the problem is the number of contradictory guides, both in posts here and on Youtube. Conflicting statements about voltage, whether it's safe to do it in parallel, whether you must do them in parallel, or you should not do them in parallel. What voltage(s) to use. Whether you should do it in a stepped manner, or that it's not necessary, or that you absolutely should not do it in a stepped manner. Etc etc.

My batteries aren't here yet, but I admit I have a lot of anxiety about what I should do once I receive them. Personal accounts like this post don't help.

 

[JoeHam]

I'm soooo done with following all these top balance suggestions. The cells were great. They didn't need this forced voltage garbage and neither did I.

That is why I chose to never top balance my new, well matched cells and have been a proponent of that policy on the forum.

Here is how I made my choice:

I tend to make decisions based on a risk/reward analysis. The supposed benefit of top balancing is increased capacity, or increased cell life or ? To be honest I'm not sure what the benefit is.

However, for the sake of discussion, let's assume that top balancing gives us a 10% increase in some measurable parameter for a cell.

We have seen reported, more than once, irreparable cell damage during the top balance exercise. When this does happen, AFAIK this has always resulted in a 100% loss of the cell.

So I have a 100% risk to the cell for maybe a 10% benefit? That would be a 10X risk/reward. I would prefer to see a risk/reward of less than a whole number.

Just my opinion.

 

[RCinFLA]

Another reason I like active balancers. With new batteries, just hook them up and wait for them to balance out before connecting battery pack to charger. Just don't make parallel cells until balanced or mate with another cell of close open voltage.

 

[Ampster]

Unless you have a BMS, I would not try to use it unless you have a good battery monitor and the time to log cell voltages at different points in the charge and discharge cycles. I would also consider clamping your remaining cells and possibly that one.

 

[JoeHam]

And that's nothing that a passive balancer won't do in regular use.

My new cells (16 of them) had a max voltage discrepancy of 0.003v.

Simply not worth the effort IMHO>

 

[sremick]

Another reason I like active balancers. With new batteries, just hook them up and wait for them to balance out before connecting battery pack to charger. Just don't make parallel cells until balanced or mate with another cell of close open voltage.

And yet I've seen more than one reputable person post that a BMS, active or otherwise, is not suitable for initial balancing and should not be used for such, and that separate balancing with a power supply should be done before hooking up the BMS.

 

[RCinFLA]

And yet I've seen more than one reputable person post that a BMS, active or otherwise, is not suitable for initial balancing and should not be used for such, and that separate balancing with a power supply should be done before hooking up the BMS.

And why is that?

 

[sremick]

And why is that?

I wish I knew. I'm just a newcomer trying to learn and make sense of things as much as I can so that when my batteries arrive I don't end up like the OP. Unfortunately I end up like the man with two clocks.

 

[RCinFLA]

And that's nothing that a passive balancer won't do in regular use.

My new cells (16 of them) had a max voltage discrepancy of 0.003v.

Simply not worth the effort IMHO>

That is not necessarily true if new cells are significantly mismatched in their state of charge. Resistor dump balancers typically don't start dumping current until 3.4 vdc and they are rather wimpy on balancing dump current compared to a strong charger current push. A higher state of charge cell could get very much overcharged before the lower state of charge cells contribute enough stack voltage to satisfy the overall charger voltage limiting settings.

When I say 'new' I mean just received group of cells whether new or used. True new cells are more likely to be SOC matched but no guarantees that truely new cells have not been sitting on the shelf for months with their own various self discharge rates.

 

[Luthj]

I don't see any issue with using a calibrated, voltage and current limited bench supply for top balancing. Though if the cells are within 25mv of each other, I am not sure it would have much value.

 

[sremick]

I don't see any issue with using a calibrated, voltage and current limited bench supply for top balancing. Though if the cells are within 25mv of each other, I am not sure it would have any value.

I'll have a CV/CC power supply, battery capacity tester, and of course a DMM ready to go when my cells arrive. I'd prefer to test each individually, using whatever slow method is safest. I don't care if it takes more than a day to balance each cell... I'm not in a rush. I just need to find a procedure that has somewhat of a consensus vs. multple conflicting guides.

 

[Luthj]

This is a good resource.

Assembling a Lithium Iron Phosphate Marine House Bank | Nordkyn Design

This article describes the process of designing, assembling and balancing a lithium battery bank for use on a yacht.

nordkyndesign.com

Method 1: Charging and Balancing Cells Using a Regulated Power Supply Unit
There are a few options available for first charging and balancing the cells. Using a regulated bench top power supply unit (PSU) is the commonly promoted approach and also the least practical and accessible for a one-off job on board – which is often the context in place when building a DIY system on an ocean cruising yacht. This process is very slow, inefficient and requires a regulated power supply unit and mains power for several days.

In some cases these constraints don’t apply or this method can be combined with the second method to “finish off” the cells, so the process is explained below, but you should prefer the second method described.

Never use a common battery charger: its output is unregulated and, even if it is able to hold without overloading and tripping, it cannot limit the voltage as the cells charge up. The guaranteed outcome will be a totally destroyed set of cells at best, or a fire. Don’t imagine for a second that you will be able to “see it coming” and prevent it. The voltage seems to remain constant forever and then rapidly rises without any warning.

You need an adjustable, regulated power supply unit to follow this process.

Parallel charging and top-balancing cells using a regulated power supply unit (PSU).
Voltage regulation is essential to ensure the target voltage cannot be exceeded.
First of all, power the PSU before connecting anything to it and never interrupt the mains for as long as there are batteries connected to it. Some PSUs are not well protected against reverse current flow and not intended for use with large capacitive loads!

If possible at all, use a PSU that is explicitly suitable to charge a battery; in doubt, use great caution as a mishap can easily damage it. If smoke escapes from it, you will never get it back in.

1. With the output disconnected, set the voltage regulation limit at 3.40-3.45V and preset the current limit (if any) to a value that won’t overload the PSU. Refer to the manual as required. In doubt, always start with a low current limit and never exceed 80% of the rated output.
2. With all the cells wired in parallel, connect the PSU, bulk charge and absorb until no current flows any more. The voltage will stay around 3.3V for a very long time before starting to rise. Charging this way can take several days. This will near-fully charge the cells without stressing them unduly, but don’t hold them at that voltage indefinitely. Keep checking up on them at least a couple of times each day. Briefly disconnect the cells and recheck the voltage limit setting on the PSU: better safe than sorry. Avoid charging the cells individually, or in batches; the whole process would take just as long, but would also result in some fully charged cells lying around for several days.
3. Once the voltage has reached the PSU output regulation limit and there is no apparent charging current any more, disconnect the cells from the PSU and increase the output voltage regulation limit to 3.60V.
4. Then, while standing by only, reconnect the cells and allow the voltage to rise up to 3.60V and stabilise for a few minutes; this normally takes little time and additional current, provided the cells were fully absorbed at the lower voltage. Whether you target 3.60V, 3.65V or even 3.70V is of no consequence or interest if you are actively monitoring the process, because these values are often reached seconds apart only.
5. Disconnect the PSU from the cells again and wait. The cells should hold above 3.50V for at least 30 minutes. If not, bring them up again and hold them for a little longer until they do. At 3.60V, you may need to insist a little more than if using 3.65 or 3.70 volts; that’s all.

As with all unattended charging of lithium batteries, some very careful thoughts must be given to the potential consequences of a failure somewhere

Using a regulated PSU, a failure – no matter how unlikely – of the unit cannot be entirely excluded and there is no other line of defence in place. Hopefully, it would just trip, but if it didn’t, it could lead to a battery fire. Someone could also come past and interfere with the equipment during charging with the same outcome.

 

[Luthj]

Continued from above.

Method 2: Charging and Balancing Cells on Board
After going about charging and balancing cells in a few different ways, I devised this method. It has since become the solution of choice for one-off lithium battery projects, because it is much more efficient and doesn’t require equipment that is not already available on board.

The idea is rapidly bulk-charging the cells using the boat’s engine and alternator and then addressing the balancing part separately.

I also consider it as potentially safer, because it is short enough to be fully supervised.

While the process usually takes a couple of hours only, it requires unfailing vigilance. This is only feasible because the timeframe is short. If you have access to a regulated PSU, proceed up to step 6 and then consider finishing using the first method.

1. Assemble the lithium cells in the final topology the bank will be using and bolt the on-board battery cables to it, as if performing a direct replacement. In some instances, this requires shifting the old lead-acid cells out of the way first. It is important that a heavy-duty connection is made between the lithium battery and the alternator.
2. Start the engine normally, run at idle for a couple of minutes and then rev it up. This will immediately result in a high alternator output. Check that the B+ (output) post of the alternator doesn’t heat up; this would indicate a bad or dirty connection and easily cause the alternator to fail. Also check all the cell connections for any temperature rise. All electrical connections should remain cold. Next, be mindful of alternator temperature. It is advisable to keep the charging current no higher than 80% of the alternator rating. Keep the engine compartment open if necessary and reduce engine revs if required. Twin-engine vessels like catamarans can (and usually should) charge with both engines. Keep a voltmeter connected directly to the bank.
3. Make a cup of tea and watch the voltage. New cells normally ship at 40-50% SOC, so a simple initial calculation can provide an idea of charging time. It is normally a matter of 1-2 hours. After remaining stagnant around 13.40V for a long time, the voltage will eventually start to rise. Periodically measure the individual cell voltages to ensure they don’t diverge abnormally and all remain below 3.60V. If this becomes tedious or distraction sets in, shut the engine down, disconnect the bank and carry on later. Should any cell reach 3.60V prematurely or, conversely, clearly lag behind the others, it is an indication that the cells weren’t in a consistent state of charge at all when sourced. This should be seen as a warning flag about a potential quality issue, like a significant difference in self-discharge rate or internal resistance.
4. The voltage will eventually reach the alternator regulation limit, normally 14.20-14.40V. If this was set higher (through the use of an external regulator typically), don’t allow it to exceed 14.40V. At this point, the individual cell voltages should still appear very even, because the cells were charged at a fairly high rate and are not full yet; only the bulk charge has completed.
5. From this point onwards, differences in cell voltages are going to start appearing. Only individual cell voltages matter. Identify the highest cell(s) and gradually reduce engine revs, so none exceed 3.60V. Keep reducing revs until down to idle, then shut the engine down. On a twin engine vessel, cut back and shut down one engine first. After about 30 minutes, most of the absorption phase is complete and the unbalanced bank cannot be charged any further without experiencing excessive cell voltage issues.
6. Disconnect and break up the bank, and now connect all the cells in parallel. If a cell is reading more than 0.1V higher or lower than the “pack”, parallel it with a small jumper cable at first to prevent any large current inrush, and connect it with the heavy link plate once the difference has subsided.
7. Once all the cells are wired in parallel, they need to be properly topped up and balanced.
   1. If significant solar capacity is available, take the solar feed from the panels (before any charge controller!) and connect it directly to the lithium bank. Solar panels are current sources and don’t care about their output voltage. They will contribute about the same current at any voltage.
   2. Alternatively, bridge from the old lead-acid batteries (or a basic battery charger) using a few metres of electrical wire (not cable!). The wire acts as a resistor, dropping the voltage and limiting the current. Depending on the length available, 2.5mm2 (12AWG) or 4.0mm2 (10AWG) are normally suitable choices. If there are 6V batteries available, bridge from 6V, otherwise bridge from 12V. The wire will heat up as a result of the voltage drop. If it gets too hot, stop and use a longer or smaller wire. Use caution and common sense.
   3. Bring all the cells up to 3.60-3.65V, disconnect and keep recharging this way until they all hold above 3.50V for at least 30 minutes. They are then full and balanced. Don’t leave the circuit closed and unattended under any circumstances; it would very quickly destroy all the cells.

This method is many times faster than parallel charging throughout, but more labour intensive and requires continued attention. It is only feasible because maintaining complete focus for a period of 2 to 3 hours is not unreasonable. If you are negligent or over-confident and leave the process unattended for any amount of time, you will likely damage or even lose the cells completely.

 

[Xerxes]

For the first part of OP........" I'm soooo done with following all these top balance suggestions. "........well you can always hire a lawyer and ask for compensation for poorly instructed advise........

There does seem to be a common theme......prior to the 280AH batteries, not much bloating threads. Most were on older in in service systems asking if this is normal or not.

With 280AH batteries now popular, by my count 5 bloated 280AH battery threads in 3 months, there has been a significant delta change.

I believe the common theme is being unattended topping off charging.
Can't see how it would happen if it was watched as there is nothing sudden about the volt increase, it just goes much faster but something you can catch if you are monitoring it.

I would not be going above 3.6V setting on the MANUAL charger ............ unless attended the whole time as you are doing an abnormal charging of the battery that can cause damage. You maybe smart enough to monitor it but you likely will not have the patience to monitor it.
Yes it is boring, .......but stop if you want to sleep, .......stop if you wan to go to work........stop if you need to sit on the throne for an extended period.....
Maybe best to set up in the garage and do while doing garage car stuff when you watch it every few minutes.
Maybe set up on the kitchen table in the evening while cooking/eating/looking at TV.
Maybe set up a mechanical 10 minute charger time that requires user intervention every 10 minutes to turn back to 10 minutes.... to keep going/reset to the maximum 10 minutes.
And you are right.......most Internet recommendation to top balance do not have these warnings of doomin gloom.....sky is flying .....run about .....screaming chicken little......
I would agree a US Surgeon General's warning .........showing lots of dead and bloated batteries at the beginning of those posts/blogs and Utub Videos ............would be way more helpful to most of the people the most times ......... and far more important/useful than the follow on top balancing recommendation advise.
They usually start out with......"hey, if you are a smart guy like me...... and want to get the most out of those expensive batteries like every smart successful person wants..... do what I do here"......and no accounting for the time it takes or stressing the consequence for doing it wrong.....

...........so hey buddy.....I am with you on this one!

........but it could be a Chinese Battery Manufacture conspiracy........where they hire or otherwise monetize the paid social media influencer's to promote doing top balance.......where they sell the original batteries way cheap........but then KAPOW! .......they make a profit on the replacement batteries.....as such no warning would be given or even suggested as the defeats the purpose......

......but It could also be that these 280AH batteries are just more sensitive or act differently than the smaller batteries.........16 Cell 280AH packcertainly has way more capacity than a 4 Cell 100Ahpack

My theory ......it is the attractiveness of the cheap DIY cell assembling ........for new folks are not familiar with these.......have no prior opportunity to experiment and ruin smaller cheaper batteries to learn on...... and that huge capacity that is not considered in the times it takes that's mentioned on those videos for the smaller cells/packs they use........... and now much larger 48 Volt 16 Cell packs instead of the prior 4 and 8 cell packs .......... makes charging take so very very very much longer ........... that folks are not adjusting too this ......compared to the 2 day effort it takes on smaller batteries/packs (1 day to parallel voltages even, 1 day to charge + topping charge) -so charging currents are set higher to go faster, combined with the typical millennial attention span...that we all we know is short (stops absorbing info at 280 characters)-combined with long long long long charging times makes them and the really old dementia folks forget about the topping off charging only realizing too late that it went to long......yep......could not resist throwing rock through that window......as I walked by.......just sayin.....


So back to the second part of your post. Not from personal experience or professional training......... but from consensus of posters/blogs/technical data there is no way to undo the damage from bloating.

Most bloating is very minor and occurs naturally over time (that I have experience with!). Its a good way to tell if cells are used as almost all well used cells will have a tiny bit of bloating (aluminum skin are the ones you notice it on the most). For bloating like on your battery as has been mentioned above you could have non-visible damage that makes the battery suspect. I would not trust it without cycling it a few times .......and even then???.......but weighed against correction/replacement cost I probably would accept if it tested as good.... but that testing part procedures is what got into trouble so I am hesitant to recommend this.....hence the recommendation to replace it. Trying to mechanically flatten these can result in more damage-so it is not recommended to Debloat, better to use as is bloated than flatten and use......unless it is to hide damage then sell to caveat emptor. I've seen a video on Utub many years back of a LiPolymer pack that bloated and was being recorded during unbloating .....results were as expected.......4th of July Spectacular...... It may have been a set-up staged video for views/clicks but it stuck in my memory for sure! I will never try to flatten a Lithium Battery-Live and let live.

I too am considering the 16X280AH batteries, or 32x280AH, or even a 48X280AH........and for me this would be an investment and not a consumer play thing consumable purchase due to the relative price compared to my income. As such I have found this forum by searching 280AH LiFePO4 and have been reading all the 280AH threads the last few weeks-including the big thread and the bigger thread!

I GREATLY APPRECIATE YOU SHARING THIS WITH US as we should ALL LEARN when one of us makes a mistake or could have done something better!

So ........too help everyone out .......can you detail what you did and maybe suggest the part that went south on you?
I am hoping to keep my 280AH bloat free so will accept all the help and advice offered.

 

[HRTKD]

Details on the charger that was used would be very helpful.

 

[newbostonconst]

I did this last week. I had 280ah 16 cells in series. They were all with in a thousandths of a volt and ran fine. I added a 17th cell to do some testing with my system and when I added it I again waited for the pack to get within a couple thousandths of a volt to the pack and inserted the 17th cell.

It expanded, I got the warning right away from the charger, glad I was home. The cell was at 4.5 volts and more expanded then pictures shown. I hadn't put the balancer on yet because I was watching constantly with a volt meter and they were all staying very close. Another reason I didn't put it on was I also thought the more equipment the more things to go wrong.

I got a replacement being shipped and a 2nd spare.

This is crazy it happened, They were with in a thousandths of a volt most of the time but I didn't top or bottom balance them. I really don't think the balancer would have been able to stop this. Maybe a BMS that can disconnect charging? but my balancer doesn't do that.

Hope others learn from this. Once I get the new cells I will likely let the air out with a pin and recompress, test, and save as a spare. Any suggestions for covering the pin hole? Epoxy? Cyanoacrylate?