The Battery Shelf after 1 year. Was this a big design mistake???

I looked at this gab for a while but did not want to think about what possibly could have happened. I knew, I had to fix it eventually...
It seems the cells have a gab between them, which is larger at the bottom than at the top. Have the cells expanded in a way that they put strain on the bus bars and terminals?
Let's investigate...
Please subscribe and join me on my journey of the Off-Grid Garage!
For more information, please check out my website with links to all the batteries, materials, devices and products I have used in my videos: off-grid-garag...
The 'Buy me a Beer🍻'-link is here (on the website, scroll all the way down):
off-grid-garag... Thank you for your support!
You can also click on the Thanks button under the video to support the channel. Thank you, if you have already!
T-Shirts, caps, mugs and more in our merch-shop:
off-grid-garag...
**** These are the batteries you are looking for ****
🔋➡EVE LF280/304 LiFePO4 cells 3.2V/280+304Ah: off-grid-garag...
🌞➡Solar charge Controllers, Inverters and accessories: off-grid-garag...
🔧➡Tools, Analysers and Testers: off-grid-garag...
📈➡ Battery Tests and Results: off-grid-garag...
🔌➡Batteries, charger and accessories: off-grid-garag...
⚡➡Cables, Inverters and Electronics: off-grid-garag...
The Sunfunkit DIY battery. Great product to build your own 12V battery. Use OGGA at checkout to get 6% off. Video Review: • The Sun Fun Kit Experi...
Best prices for Victron gear in Australia: Auto Parts Co has you covered.
www.autopartsc...
(they have 4WD parts and accessories too)
Take a live sneak peek at the Off-Grid-Garage in the Victron VRM World (link at top of the page):
off-grid-garag...
Here is my Tesla referral link, if you want to buy any Tesla accessories or even order a vehicle. This is a great way to support my channel. Thanks a lot to everyone who have used it so far 🙏 ts.la/stefan96963
My other (German) KZbin channels:
/ offgridgarageaustralia
Please don't leave any links in your reply. KZbin will not publish your comment in this case.
If you decide to sent me an email, I really appreciate your time and effort for doing this. However, please consider leaving a comment under my videos instead as I may not be able to reply to your email due to the sheer amount of messages I'm receiving.

[@carlosgaspar74]

Hi Andy. I think it's time to revisit this topic once again no? Almost two years... Gaps, spacing, visual condition and swelling. Always appreciated the capacity test as cells age. Keep up the amazing work.

[@iancassie9840]

I REALLY LIKE that you go first and we get to watch with 20/20 hindsight thanks for your passion

[@soerensprenger8381]

„Compression is wasted“ - Andy. 😂 I do compression and also use flexible busbars to avoid stress on the terminals. You could discharge to 30% and compress then. Dont know if this makes sense after this time of use. You could compress with a steel plate which maybe fit in your shelf.

[@Carsten-PV-DIY]

Very reasonable approach. Agree with you. Then the minimum electelyte gas state ist active and less pressure within the cell. 👍😎

[@ragemonkey3163]

@@Carsten-PV-DIY I agree with soeren. you may end up with a fire risk form a ruptured cell if these aren't compressed. you may wish to replace the busbars after compression as well since dimensions have changed

[@Carsten-PV-DIY]

@@ragemonkey3163 Yes, Therefore my comment. I always recommend after chemical Component analysis of a lfp cell to compress for the first cycles to avoid the de-shape of the body cell. 😉👍. I like that Andy is changing his mind.

[@PavolFilek]

But compression have to be constant, at all temps and C rates. So how to do that properly ?

[@Carsten-PV-DIY]

@@PavolFilek Use a Temperature stable environment and prepare a battery Revision in a useful Frequency e.g. quarterly or at least annually. 😉Environment can be controlled.

[@9111logic]

I'm surprised about your reaction Andy, you knew that this was going to happen from the very beginning but you decided, and actually stated, to ignore the compression factor. Although I would agree that torque values are open to discussion and bearing in mind that totally preventing the natural expansion might, and I repeat, might be also not too beneficial, I would at the very least keep the batteries in a confined space in order to minimise the problem. At this point, I would not be so sure if compressing them after usage would improve things, perhaps stopping them from further bulging ?

[@johnq8792]

Mine are compressed

[@9111logic]

@@peterking1134 only testing will tell us and, in fairness, Andy's channel is all about testing so no finger pointing😍

[@oilpressing]

@@peterking1134 Ya Andy said something else would kill them first!

[@9111logic]

I am going to build at least one to add to my existing 5kW one and I will certainly bring them close enough to prevent the swelling but I don't think I'm going to apply any major torque to them, just enough to avoid the bus bars to be the "straight jacket" of my unit 😍

[@innocentusangira789]

We need to learn more..... I have my used CALB cells which are more than 8yrs old but yet they are not swollen....However I have got another 16 cells parallel to the CALB cell swollen to extent of being written off......

[@allynonderdonk7577]

Gotta say Mike did not have his cells completely compressed. Those rubberized spacers he had just didn't work as it allowed the cells to compress the rubbery material and expand where there wasnt rubber. I've had a similar bank for two years, with those flexible cutting mats cut up between cells. They don't compress and insulate. I bought a 12ft threaded rod product from the electrical section and cut it up with 1 inch boards cut to fit the ends used the rods to compress. I just checked mine and there is no movement/swelling whatsoever. I would put enough pressure on to snug up the swollen electrode sections at least. You can't put them back to normal, but you can stop it from getting worse. Though I put all mine in a single row for compression purposes, you might need to find a way to get rods in the middle of your bank or stiffer end caps to make it work in your configuration. My rack can roll around as I made it from wood posts and 2/4s on industrial castors. Its so easy to work on...

[@davidcox8961]

I did things a bit differently Andy. I placed a 1/16 inch thick piece of rubber on each corner of the cells. I did not compress the pack but I did fit them tightly into the 3/4 inch plywood box I made. It seems to work. All I have are eight cells for a 24 V battery. 280 amp hr EVE cells. Cheers!

[@mikecreamer8308]

Thanks for being honest with all your mistakes. It helps alot of people to learn from them. I did the same on an 8s setup and have similar results. Just get wider busbars and expand the pack. Looks as if you have enough room.

[@OffGridGarageAustralia]

Thanks Mike. I'm not considering the non-compression of the cells as a mistake. I would have done it a bit differently now but still would not compress as such.

[@mikecreamer8308]

@@OffGridGarageAustralia big fan of the offgrid garage!

[@higamato3811]

@@OffGridGarageAustralia But now we are gespannt to learn what exactly it is that you would do differently next time and what is the enigmatic "as such" supposed to mean?

[@easypowerwall]

I have compressed them from the start, happy my 64 cells will sit tight for the rest of their life.

[@markbrettnell3503]

the cell definitely moved as you untightened the first nut. I almost wonder if cell compression is useful more for minimizing strain on the cell posts from the cells swelling then adding cycles....🤔

[@QuantumMarmalade]

stranded wire and ring terminals.

[@Zorlig]

The funny thing is that the reason for not compressing was to avoid stress on terminals!

[@john0270]

I plan on just making a tight fitting wooden box for my 12 volt cells I plan on building.... if they ever make it from China. Nothing elaborate, just something hold the cells snuggly, mount some handles and maybe a bms/balancer.

[@Zorlig]

@@john0270 that will likely expand just like these

[@Bluntask]

It does seem that clamping the batteries keeps some strain off the posts. Are flexible bus bars just as good ( conductive) as solid? And, what material is best?

[@XTreMe2k6]

7:24 "Something you cannot prevent" ??? Well, as I recall, you decided to ignore the compression factor. I was never a fan of not compressing the cells in the first place. That is why I used 4 threaded rods with resin plates between each cell on all of my cells, Thank god no swelling so far and my cells are in use since mid 2021.

[@randylenart9674]

That's why I have tie rods holding mine together from new and all is well after two years 😊

[@kevinmills5293]

I’ve seen many EV packs disassembled and they are all constrained/compressed. If nothing else, it relieves stress on the terminals. I constrained my cells when I built the battery and there is no strain relief on the bus bars. They are less than a year old so it’s too early to say if I’ve done the right thing or not.

[@roadeycarl]

Even if you decide not to compress / restrict the cells from anymore expansion - it may be a good idea insulate between the cells in case they expand to the point that the only isolation between the cells are the blue pvc film.

[@GTrainRx7]

I have to point out, Andy ALWAYS said that compression was of no use in getting better performance. This is a different issue, and something I don't believe I have seen anyone comment on when compressing batteries. So chin up Andy, you caught it in time, you learnt from it, nice work!

[@SoundzAlive1]

Hi Andy, I wrap the cells with a clear, wide and thick tape something like Kapton tape which is super strong and easy to use. Bought from Bunnings. André in Sydney

[@repairman2be250]

You do what with that exactly?

[@SoundzAlive1]

@@repairman2be250 Wrap around batteries to compress them. Pull as tight as you can and that gives a firm compression. André in Sydney

[@repairman2be250]

@@SoundzAlive1 Cheers Mate.

[@bildad1234]

Yes Kapton tape is super strong

[@nielswehr7351]

sounds good and that’s the same way how the 12v LFP battery’s are compressed that you can by from ali. I would recommend this method with 4 supports on the outer corners to take stress from them as well.

[@phillipmoore4492]

Hi Andy Compression of the cells is more about making sure the terminals over time don't pull on the bus bars and damage the battery's. You could use flexible busbars or increase the size of the slot hole in the busbars to allow more movement. Cheers Phil

[@OffGridGarageAustralia]

Yes, that's a good point. I really doubt anyone will see a benefit in cycle life when compressing their cells.

[@DennisLaDenmark]

I have made a wood box that fits all 16 cells in the same order as yours. The cells are not compressed but is slided into the box. There is no room for expansion. I will not put compression on the cells from the beginning, but just keep them in place. Thanks Andy for your great videos.

[@OffGridGarageAustralia]

They will expand a bit though so the wood maybe will take this force and compress at the ends.

[@republicridge5894]

Very important! Long term you need to have a sliding slot on the busbars. Mine tore out the stud by egg shaping the stud threaded hole. Screw the stud down, and the stud wobbles back and forth from the swelling

[@jimeverett8998]

Hi Andy, Love your channel. Great work! You mentioned at end of the video that you don't have room to compress using 3/4" plywood. I use 1/4" sheet Aluminum and it works great.

[@mobiuslooped1551]

Me too. 6061 .025" AL plates on each end of the pack, with six threaded tie-rods, inside square tubes that lock into the channels on the sides of the batteries. Three tie-rods on each side of the pack. Massive overkill, I thought at the time, but not anymore...

[@Knightliner69]

Have used aluminum plates and a 1mm pcb for isolation on the side to the batteries on my pack. Works perfect. Not a big fan having wood around a battery. For compressing you can ( if you decide to do it ) try the solution Jens from Meine Energiewende did with this packaging straps. Looks like a very easy and good solution.

[@TheRonskiman]

I have also used 10mm alluminium plate. 1mm PCB between each cell and used a special foam at either end, and flexible laminated busbars. My 16 cell battery rack is a lot more compact than Andys, it will fit.

[@chuxxsss]

Morning Andy, still raining down here. But I worked out a fault on my system, thank goodness.

[@OffGridGarageAustralia]

You are getting there slowly...

[@ssoffshore5111]

As I stated last year, I would've compressed them from the beginning, and I still would do so now... EDIT: And I'd still recommend using flexible busbars!

[@ssoffshore5111]

BTW, I have seen several people compress swollen cells and over time they do unswell somewhat. I'd recommend using springs rated to the appropriate force to keep it consistent.

[@KossuJahvetti]

What type of flexible bars you recommend? Have you measured the resistance of those?

[@jamieandrews3238]

​@@KossuJahvetti flexi bus bars are just solid with a hump in the middle that get allow stretch.

[@onthelake9554]

@@jamieandrews3238 No , those are not very flexible at all . They make a braided one .

[@yooper423]

My opinion is to leave them as they are. They are, after, Storage quality cells. I would make sure the cells are as far apart as the buss bars will allow. Then check the gap with a spacer, and follow up in 6 months.

[@SylwerDragon]

I think it is normal reaction. same happen to my cells.. you can't avoid it if they are not compressed. make extra space is ok..but i would monitor it from time to time. i would add thin plastic sheet so they can't touch each other but that is about it. no need to worry. Compress can be done at the begining not now. now it would be not good at all.

[@ThaVoodoo1]

Andy, I asked ChatGTP should Prismatic cells be compressed together for longevity. This is the reply. In general, compressing the cells together can help to increase the mechanical stability and reduce the internal resistance of the pack, which can improve the overall performance and longevity of the pack. However, it's essential to ensure that the compression force is not excessive, which can damage the cells and reduce their lifespan. Moreover, the compression force should be applied uniformly across all the cells to prevent any deformation or damage to individual cells. This can be achieved by using appropriate compression materials and techniques.

[@repairman2be250]

User Max Meyer said: ...manufacturer specifies a compression of 300 kgf.

[@repairman2be250]

Ask ChatGTP for a precise howto DIY.

[@micropower8]

The housing of the cell has a different shape and this is a problem. I have seen in his video (as he laid the ruler across the side of the cell) a height difference of ~4mm. What material would you use? I have the idea of using fabric enhanced silicone, like the material what we use as insulator between a TO-220 transistor and the heat-sink. It is possible to compress it, without the silicone being squeezed out on the side. But is must be ~5mm wide. Any better ideas?

[@decebalpopescu3824]

Max Meyer about the clamping force.I had them mounted and tightened between two rows of jobs one up and one down with 6mm screws.After i have to dismounted to go from 16S,2P on 17S,2P batteries or inflated 40 mm,by 5mm each, from 36 to 41 mm each.When i saw Something like that i got scared. I fitted and tightened the batteries between the yokes to original size 36mm,and now it works again great (17×36=612),in reality they have 630,only millimeter more for each battery (Liitokala 105 Ah).

[@sirmonsterle]

I see the same behavior at my cells. I readjust the busbars once a year to take away the forces from the electrodes and put a insulation in between to make sure they are isolated against each other. Maybe I start to compress the cells in later projects

[@RobbieHLM]

Just finished my shelf 2 weeks and copied a lot from you. Good to see what's happening. I'll keep them uncompressed bul will move them apart from each other as much as the flexible busbars allow.

[@OffGridGarageAustralia]

Just monitor it and adjust over time if necessary.

[@mikelamb6946]

I made my buss bars from battery cable so the cells can expand and contract as they please...Andy.. thanks for all your information over the years!

[@john0270]

I often wonder if this would work, how long have you ran it this way? What gage wires/what size cells?

[@SkypowerwithKarl]

Andy At this point I think it’s too late to compress. The risk of damaging a cell is too great. You have done the best you can by giving them more room and not having tension on the terminals. Technically, you’re not even supposed to compress after a top balance. The cells need to compressed from the beginning- balance to service or don’t do it at all. You can disassemble a compressed battery but only at a low state of charge, cool and for a limited time then re-compress soon. I changed my batteries from a 2P arrangement to two banks of 16 and the batteries were very flat a year later.

[@claib]

hey Andy this is part of the game exploring things and learn from mistakes. Learn > Share > repeat regarding compression there are more myths than know-how and know-why!! out there. stay charged :-)

[@OffGridGarageAustralia]

Thanks Chris. One of the main purposes of the channel. Including making mistakes. Not that I see this as a mistake but still happy to share my thoughts...

[@ghostwriter6699]

There is a limit to their expansion -- and i would say that after a full year of use you have maximized the amount of expansion that you will see. The only way that they are going to expand any further is if you start hitting them constantly with 2C. Personally I always either compress or at least strap my batteries -- but at this point -- with yours -- I think it is what it is and that I would just monitor. I would however loose all of my bus bars and then retighten ...

[@john_in_phoenix]

I agree, he has reached about the maximum expansion as long as he doesn't abuse the cells.

[@Zorlig]

I bet they keep expanding. If you care about expansion you have to compress.

[@QuantumMarmalade]

if you care about expansion, you have to cell match.

[@AhLoui]

Fully agree! Cells are expanding and shrinking (if not compressed), depending on the SoC and rate of charging. I have cells in use since 5 years+ and never compressed them. They are a bit bulky but nothing which makes me worry... Leave it as it is, Andy 😉

[@MrLeecavturbo]

Is there any manufacturer guidance to not compress ? It seems logical that if something wants to expand (chemical reaction in a substance) and you keep it contained in its original space pressure will increase ? Can that pressure then lead to other reaction ?

[@niclas.lindstrom]

Why do you see this as a problem? Your shelf has plenty of space so a little expanding is not a problem but totally expexted. I would look at it as just an esthetic thing. I think it was a good move to loosen your busbars and rearrange for a consistent gap just to relieve the force on the terminals. No need to worry!

[@OffGridGarageAustralia]

I don't see it as a problem, I'm just showing what I experience. I won't install any compression but will take the tension of the terminals for the other two banks as well and space them out a bit more.

[@stefankrimbacher7917]

Compression is a must have. As written in the description of this cell there should be a force of 3000 Newton (300kgf). Charging and discharging occur volume changes. The problem is, if there is no compression this effect is not reversible. Before charging the first time, compression should be applied and use flexible bus bars to avoid damages around the terminals. That`s all you need. Otherwise you damage the cells over long time use ! I use 16 packages with 8 cells in series each - 128 cells 280Ah in total My compression works with 8 threaded rods for one package (4 on each side) with springs to adjust the right force and one strong 20mm aluminium plate with a thin insulation sheet of PVC at each end. Qishou tested it in the same way, this means constant force to face temperature changes.

[@mfgxl]

I put a piece of 2 x 6, or 2 x 8 wood to be wider than the cell on each end and than use a ratchet strap to cinch them together. My main thought for doing this was to reduce the chance of stressing the terminals. Simple, low cost solution.

[@nihongobenkyoshimasu3190]

It would have been interesting to compare one pack using soft connection bars with one pack with rigid connection bars. To see if there was the same zig-zag or if the cells would have stay parallel to each other.

[@bob1505]

Gripped by the tyranny of trivia. Andy you have shown tremendous attention to detail. From what I can see it is a beautifully clean installation. My suggestion is that you use packaged batteries that preclude your ability to see the individual cells. John Emmert's advice below this is probably good advice. Remember you are an electrician not a machinist. It drives me crazy when people expect electronic and electrical components to retain a percent or so of measured accuracy. Keep an eye on the system's performance and enjoy the free juice. Calm down, you did a really really nice job. Enjoy it!

[@OffGridGarageAustralia]

Thanks Bob. This is a big experiment, I'm doing. Uncompressed cells, solar under trees,... much to experiment and learn from all this.

[@onthelake9554]

All battery manufacturers restrain expansion and cell manufacturers recommend it . I don't feel it should be questioned , just done. Flexible buss bars as well in my opinion.

[@offgridd]

Hi Andy, I would recommend you to use silicone separator plates of 2mm thick between all cells and then compress between two Aluminium plates that are pushed towards each other with 4 springs and rods at 100-150kG. I suspect shore A 40-60 would do the trick but that's just a gut feeling. That will be my approach. Monday my 40 "Smurfs" will arrive at my doorstep and I have already contact with two companies that make flexible and semi-flexible busbars (multilayer) since there are very little companies making these for side by side LF280K EVE cells with two m6 holes on each pole.

[@walterweese2527]

Frohe Ostern 🐇🐰🐣

[@repairman2be250]

Vielen Dank, Mate.

[@Woodyjims-shack]

The Seplos system using eve foam looked pretty good so I built my battery using the same technique. The technical docs say to use compression I believe.

[@OffGridGarageAustralia]

Yes, exactly. I think they nailed it with their design and keep the cells firm but still aloow for some expansion through the foam.

[@wayne8113]

🤔 Thanks Andy

[@OffGridGarageAustralia]

Thanks, Wayne.

[@Theaveragenerd2000]

Most lifepo4 cells expand over time. My concern would be more focused on the force that the expansion puts on the anode and cathode rods.

[@pedromoonunit430]

Funnily enough I watched the video about not needing compression only last night. 😀

[@user-tj5nk7lb8l]

Cant understand why flexible busbars are mandatory? Think of the stress on the post from even a small expansion? Tip I use domestic copper pipe wall clips, ca 20p each good for 50A, double up for 100A. You can solder you bms leads directly onto the bridge and add an auto style spade push connector for convenience. Put a loose pvc sleeve over to protect

[@FutureSystem738]

I feel your pain Andy. I went through this decision process when I built my 4s Winston 400Ah pack for the caravan in late 2015. I went with compression in the end, and it seems to have worked well as far as I know. (I can’t actually look at the individual cells unless I disassemble the whole lot- … which is not going to happen.) The Winston cells certainly have absolutely minimal degradation (capacity loss) over that 6.5 year time frame. I’m leaning towards compression AND flexible Busbars for my EVE cells, but is it possibly too late already? Mine have less cycles than yours, and a cooler environment, and have no noticeable swelling … yet. Meanwhile I am guessing that the swelling doesn’t really matter much at all if the Busbars are flexible. 🤔

[@OffGridGarageAustralia]

I would have done the same for you mobile set up, Dave. You want to prevent the cells from moving when the vehicle is in motion, so compression is a must in these cases.

[@MMMM2MMMM2MMMM]

Take 2 pieces of cuttingboard and 4 metal bars and 4 threaded rods. You can raise your compression bars a bit higher that way. I have compressed my battery's and did not get any bulging (yet). I use low charging current too, this might have helped me prevent the cells to bulge too.

[@MMMM2MMMM2MMMM]

I'm using some foam between each cell too. If expension might happen, it will just compress the foam a little more. I would suggest to mix all cells. I do this every year. No idea if it does any good, but it does no harm either.

[@rjinhobart7748]

I'd realign then restrain them, not compress. Just enough to prevent the misalignment you saw. This will relieve pressure on the busbars fasteners and the cell terminals.

[@OffGridGarageAustralia]

Why should I restrain them though if there is space in between the cells? There would be no strain on the terminals.

[@edwardvanhazendonk]

Your cells cycle through a lot of temperature changes in a year, summers really hot and winters not to cool. Compression might solve some bits but temperature expansion may put strain on your terminals. If you check regularly if the space between the cells don't shrink to touch the others cells you are probably good. If you compress your cells and a cell will rogue, you will notice it when it's probably to late (as you can see your cells and look at them often, for others this might differ). As your busbars are inflexible keeping the space is mandatory to not strain the uncompressed cells. Happy easter and keep the sun shining!

[@OffGridGarageAustralia]

Thanks a lot Edward. Yes, I look at them often. Maybe too often 😊 I will have some sort of fixation for them as a solution...

[@marcoarpago]

If you have 2 spare cells that are very swollen with maximum expansion (the worst cells you could find in the garage) check if you can still use the current busbars or if you have to make the terminal hole longer to leave at least 1mm of gap. The compression solution would be a real pain in the project.

[@OffGridGarageAustralia]

All busbar still fit. A bit of expansion is normal.

[@ro_sher]

Expanding the battery can damage the terminals on the cells. The resistance at the terminal may increase sharply, leading to heating.

[@Skeptic100100]

Well... you are only a few weeks ahead of me. I DID choose to compress but I am not willing at this point to pull everything apart to check for swelling. I fear that they have. Like you, I don't know if it matters with regards to swelling. I will not do anything until I see a problem. I can only imagine where we will be in another year from now.

[@OffGridGarageAustralia]

Don't take it apart just for the sake of checking. A bit of swelling as mine have is normal and cannot be prevented. All good.

[@ciciedee5474]

If only some technical support paper had a recommendation for battery compression

[@theobauck258]

Hi Andy, AS Always a good Video about learning more in technics of lifepo4 batteries. In the Case of expanded cells my thoughts are... Put insolation Sheets between the cells, Put flexi busbars on the cells and Install PC Fans, one on one end for sucking fresh and cool Air in and on the other end to pulling Air Out. Just Like other commentators Said, there is No need to RIP all apart. There is normal Expansion in the cells after amount of time and a afterwards compression is in your Case Not zielführend. After you ripped all apart, you have to let sit the cells for a quite of time to come down before you compress them and Put them Back in the shelf. Greetings from "waiting for the sun comes Out" Germany

[@OffGridGarageAustralia]

Thanks Theo. No fans for me though. too much dust and insects. I have another solution to get rid of all the heat before next summer...

[@maxmeyer7299]

Well, Andy is now showing us how it looks after just under a year. In 5 years, he will show us why the manufacturer specifies a compression of 300 kgf. Then we will see how much capacity loss it really is and we remember his calculation about the cycles in his video where he explains why he did not do it. So the entertainment here on the channel remains secured.

[@Brad656]

As much as I agree, no need to be a smart arse !!

[@jonasstahl9826]

I assume by your name that you are a german, the channel "Zerobrain" had a video where he interviewt a battery expert that explains very good why you should compress them.

[@randomguy7253]

@@jonasstahl9826 I was gonna mention that video, too. But he also said that you can't avoid the belly because the forces that produce it are way higher than the compression.

[@Zorlig]

You read my mind! I knew this video, and the next one you referenced would come eventually after he rejected the battery install instructions.

[@Zorlig]

​@@randomguy7253 yeah he didn't know what he was talking about. I have a 24 long string that had zero expansion from low to high capacity and still zero over years now - because it was properly compressed

[@davinmullan]

I think you should compress them. I built my 48kwh battery with Nissan leaf cells and they must be compressed to prevent expansion

[@OffGridGarageAustralia]

They are pouch cells? Or just not have the firm case around them as the EVE cells have.

[@olafmackenberg5018]

Unless you change your busbars to the ones that allow mechanical work I personally think is is necessary to compress the battery as you limit the amount of mechanical energy between the cells and in the connection of the busbars. I think this is the main advantage of compression.

[@nrgia]

I thought the same. Thats the main plus of compression. You eliminate the mechanical stress on the battery terminals.

[@danielglang6312]

As the batteries swell, the bulge in the middle causes (allows) the electrolyte within to sink to a lower level which deprives the top of the batteries of the fluid they need to function properly. This lack of electrolyte at the top might cause further resistance and heat at the top but at least does somewhat lower the working capacity of the sells.

[@PhilippeCJR]

@@danielglang6312 sounds good, where you got this from? any info/video/docs? :)

[@danielglang6312]

@@PhilippeCJR I have no references, only a logical belief based on observance of circumstances where liquids settle downwards as containers expand outward. It seems logical that deprived of the electrolyte which causes the batteries to function, they lose ability to function correctly.

[@PhilippeCJR]

@@danielglang6312 ok, but what if the liquid is overfilled standard with lets say 120%. Then with any expansion, it will not cause any issue. Btw i have compressed my pack but i have 16x120ah

[@robben8704]

I had same problem and it snapped the terminals off I have now compressed. It more to limit the stress on the terminals.

[@OffGridGarageAustralia]

Oh, wow, that's a lot of force then on these contacts. I had some space in between the cells from the beginning and the force was not strong at all in my case. Yeah, but thinking about a different solution now...

[@paulhardie9450]

Andy if nothing else your expanding our knowledge of such things in Sunny Hot Australia 🇦🇺 and I for one Thank you .Your the Mad scientist 👨‍🔬 , The Jekyll who won’t hide 👍 could one say the Power Ranger

[@upnorthandpersonal]

Compression is a misnomer - fixture is a better term. Having them in a fixture prevents the electrodes from expanding which can cause delamination besides just swelling. In addition it takes the stress away from the terminals, even though I go with flexible bus bars always (and go through the trouble of making them myself). If I were in your position, I'd find a way to have a fixture.

[@OffGridGarageAustralia]

I may have found a solution... It's called fixture in the EVE specs, so that is the right term.

[@bertherta494]

Understand your point on fixture, but how are you doing this. Are you using PCB (1mm PCB/epoxy sheet or similar) the same size as the cell between cells or only placing a form of spacer at the corners of the cells?

[@upnorthandpersonal]

@@bertherta494 In the past I didn't put anything between the batteries. Right now, something thin and rigid, like PCB/fiberglass.

[@OffGridGarageAustralia]

@@bertherta494 You can either use the Seplos method and put some EVA foam in between the cells before you compress or you use just a 'frame' to keep the cells fixated but let them contract/compress... I'll show some solution on the channel...

[@MrDingaling007]

I took every precaution with these thin cased blue wrapped cells. Went with flexible braid busbars and a solid frame fixture. Seen too many photos of swelled cells and stressed busbars/terminals.

[@OffGridGarageAustralia]

Swelling cells usually come from overcharging. Under normal operation such expansion is normal.

[@gumpster6]

I would just repeat on the other 2 shelves what you did on the top. Relieve the stress on the terminals and give them that small gap... then check in another year to see if they have filled in the gap. I think trying to compress at this point would just be a headache. If they keep expanding, you can wrap one of those nylon webbing straps around the middle of the pack and call it good.

[@OffGridGarageAustralia]

Yep, that's what I will do. I don't think they will expand any further. This is just what they do and as we saw in Mike's video, happens even under compression.

[@Aconda]

What you just did was the best to do to release possibly tension on the bus bars fastening. No compression is ok. Would not bother to install compression at this time.

[@OffGridGarageAustralia]

Yep, I'll do the same on the other batteries below and leave them as they are.

[@greg6609]

I'm about to put my cells in service and I'm wandering if I should compress or not. But I don't have any space. Thanks for bringing this up.

[@rozarijorodin]

If you compress your cells sideway, they will expand other way... It is common reactions for the LFP4 battery cells... So... There is no reason for compressing them... If you have 3 of the 100Ah cells in parallel, you will not notice that... But it is also happening, just less then on 300Ah cells... You can see that many batteries from the factory they are using 100Ah or max 200Ah in the battery pack... The main reason is because the expansion is less then the bigger cells... Don't worry Andy... Give them the space and they will work for you...

[@Paul_______]

i compressed mine after 6mo and no additional swelling has happened. i used 2 0.5mm yellow spacers between each cell and flexible bus bars then compressed with a ratchet strap

[@OffGridGarageAustralia]

Thanks for sharing. I think they won't swell any further, that is all they naturally do.

[@Paul_______]

@OffGridGarageAustralia I think you're right but I was caught up in paranoia. Figured better safe than sorry.

[@davidabineri908]

Now you will be able to compare the bank you re-assembled with the other banks left alone in another year.

[@OffGridGarageAustralia]

I have to re-arrange the other two banks as well to take off the force and allow for more space in between them.

[@Silvije2]

Reorient all cells in a way when you connect two adjacent cells with a bus bar they are close to each other with their narrow side, that way you dont have any stress on terminals whatever happens with bulging... but you may end with snake like arrangement on your shelf

[@davebutler3905]

Good idea!

[@dustins4194]

I chose to box my cells in and keep them from moving. I didn't compress, but I boxed them in nice and tightly so I should never see stress on the terminals. I have to say, I was very skeptical of your method of leaving a gap after seeing so many batteries bloated more than the gap you left. I know it's all theoretical at this point, but I do think gapping them is not the best way to go. These are going to continue to bloat over time... you will have the same problem again in a few months and you'll then have to figure something else out.

[@OffGridGarageAustralia]

EVE is talking about a fixture, not a compression, so you did the right thing. They won't bloat any further.

[@dustins4194]

@@OffGridGarageAustralia love your channel and look forward to the next improvement. I've done many of your same projects.

[@abelramos8652]

The problem is the word compress … you don’t have to compress just hold them (ok compress them but only a bit!)

[@OffGridGarageAustralia]

Yes, they are talking about a fixation, not a compression. Seplos does a good job with that in their MASON battery.

[@PabloTBrave]

Foam in between cells and compress like both Seplos battery kits you bought if they didn't think batteries needed that they would have saved money and not bothered

[@micropower8]

Timestamp 5:00 - there was movement as you have opened the connection. It is good visible if you switch 10 seconds back and forward. Because of this changes in thickness, I have buy flexible connectors. You could use some with a bended U-shape form in the middle as spring too. Because of the swelling of the cells: 1. Air: A specialist said, there is a tiny bit of air in the material, even if the layers are put together in near vacuum. The air going from the material (carbon) and accumulates between the layers of the battery and this is reducing the capacity. If you compress the cells, then this air will still go out of the material with time, but upwards to the empty area of the cell and accumulate there. With the loading and unloading of the cell, there is a pumping effect, so the air will go upwards with time, out of the area with the layers. The orientation is important, but you have done it right. The cells may not be laid down at one of the other sides, because the "empty" reservoir is at the top. There the air can be without making problems. 2. Chemical expansion: What I know is the chemical structure of the molecules inside of the cell changing if they are fully loaded and the chemistry of the cell is a natural thing, so you have to calculate with a bit expansion. But the producer of the cells (how you said in an other video) explain that the endurance is better. Maybe the capacity will not be at 80% after 4 years. For me this is a argument. Possibly the expense is not so high to do this? I am a bit worried about the pressure inside of the cell. Is there a possibility to damage the cell if the pressure is so high? (300Ah -> 300kg on the big side) The shape is not flat, it looks like a wave with 4mm difference between the highest point and the lowest. (Timestamp 7:29) What material should I use? A ordinary FR4 PCB would not spread the force on the whole surface, we would have some force-spots were the electrodes are. I think silicone would be to soft if I would use 5mm thick layers between every cell. With 300kg of pressure It would possibly push out at the sides. Or possibly 5mm silicone sheets with fabric inside? This must be tested.

[@darrenkamalu9047]

Where did you get your flexible connectors?

[@darrenkamalu9047]

They did move.

[@jackoneil3933]

Interesting discovery and point Andy, thanks for sharing. I'm wondering if you could do any harm by compressing cells that have already expanded, any more than if they were compressed in the first place? I recently disassembled a couple of 12 V prismatic LFE batteries wired in sires, that had expanded and failed would you friend had used in his experimental aircraft. After only two years of service and 60 flights the pouch cells had expanded dramatically, to the point of deforming the outer case.I suspect this might have been caused by a charging with a 60amp, 24V Alternator, or that the two batteries might have become unbalanced. We cut open several of the pouch cells And looking at how thin the polymer membranes were between the foil plates and how in spots the membrane an foils appeared to be degrading from pressure, we were a bit concerned for a potential of an internal short, but I suspect that the battery would likely fail in terms of capacity before a short might happen. How long is the factory warranty on those cells Andy? I sent this video to a friend I've mentioned before, who stopped doing off grid solar installations after losing thousands of dollars replacing failed Chinese Prismatic cells for customers. He used 'B' and 'A' Grade cells and after 1 year noticed some swelling, a bit worse than what you have there Andy, and then within the next nine months to a year, they swelled a lot more more and Cells started failing. He didn't compress his cells, and while I have a hard time figuring a mechanism to where not compressing cells might lead them to fail, when I think back to what I saw when we unrolled the prismatic pouch cells in the 12v LFE batteries, where did appear to be cracked dry spots in the electrolyte, as if the foils and electrolyte had separated or you might say 'de-laminated' from each other. It's not due to compression, lack of compression or possibly overcharging creating outgassing that force the layers apart? I don't know, but my got the impression was that it was a manufacturing quality issue combined with with moderate charging amps and inherent expansion that caused the failure of both batteries. My expectation would be that if it was common for cells to start failing within the warranty period, or even within two or three years, that most of these Chinese battery companies would be out of business in a few years.

[@repairman2be250]

I like your explanation. I don't suppose you have a video or photos of those cells taken apart.

[@MiranPayman]

I feel sad for you Andy 😢😢 i bought assembled packages to have factory compresson, so this would not happen. I hope this will not make them lose capacity very fast. I had an issue with phone batteries getting belly and pushing the screen apart. If the issue get worse i advise you to replace those busbars with flexible copper wire busbars.

[@OffGridGarageAustralia]

You will be surprised if you take your battery apart and the cells look exactly like mine. Swelling cannot be prevented under any circumstances.

[@bgbalz75]

Hi Andy, We all expand and sag with age, You have the unique opportunity to do an experiment. Leave one set alone (Control), Compress the second and space the third.

[@raytry69]

Mistakes are the best teachers.

[@mjpbase1]

Andy, maybe compress one battery, re-space another (as you just did) and don't touch the third as a control for a long-term test.

[@ralfkremer8882]

The cells are specified with +-0,5 cm. Cannot be avoided by any force. That is why they should be connected flexible instead of using bus-bars.

[@OffGridGarageAustralia]

Or with space in between so they can expand and contract.

[@ralfkremer8882]

@@OffGridGarageAustralia contracting and expansion should not be the core of the problem. I think hard fixing with bus bars is the problem. In this case electrical connection is under stress. Better connect with flexible cables and don’t worry about the „cell breathing“. 😉

[@DanBurgaud]

I had the same issue. I re-arranged them such that they are spaced as apart as possible, limited only by the busbars. Now, there is a space of about 4mm between. Of course over time these cells will bloat even more, then I am out of solution. I personally prefer to have spaces in between cells for cooling/ventilation reasons. But this expansion questions our initial decision; we should have compressed them in the first place.

[@OffGridGarageAustralia]

They don't swell any further. The swelling I have shown is normal and even occurs when compressed as e have seen in Mike's video. It cannot be prevented.

[@xNYCMarc]

Didn't you do a video not long ago that concluded that compression is bullshit? (Which I completely agree with). I've been running my mixed Calb and Eve cell bank for 8 years now and never had compression on them. They are doing the same thing as yours where it looks like there are two cylinders inside. But everything is totally fine. There's nothing to worry about.

[@edc1569]

Stress on the electrodes from solid bus bars is something to worry about

[@xNYCMarc]

@@edc1569 After nearly 10 years of daily cycling these cells and abusing them in the early days when I didn’t know any better, I disagree that it’s a concern at all. I mean, you can be concerned about it. But it isn’t a warranted concern.

[@zarbonida]

​@@xNYCMarc thank you. Now i can sleep calm

[@xNYCMarc]

@@zarbonida Yes. You should sleep calm. These batteries are exceptionally safe, even when deliberately mistreated, let alone not doing anything to them that you’re not supposed to be doing.

[@d3claes]

Will the cells expand even more in the following months, or is there a maximum expansion? What is your experience with your batteries?

[@christophec252]

This is not a good question you ask Andy! The real important question is: they have expend yes. And ? What’s the problem? Is get more place for dilatation is good. Is compressing something that want to expend will be damaged? When you build a house. It’s normal to have dilation joins ? Same thing for the building. If you make something rigid. It will brake. A high building can move about 2 meters on top. and dilatation is normal. Making something rigid will brake for sure in future. Is cells are same? This is the question.

[@OffGridGarageAustralia]

Great comment, Christophe. I will have a solution for that issue soon hopefully.

[@traviswansai2784]

Andy I resoled this issue by 3 D printing top and bottom holders with built in spacers. Anyone with a large 3D printer can print the holders for you. Though I would like to see you buy your own printer and do this yourself.

[@OffGridGarageAustralia]

Yes, someone from CA has send me the details already. It seems, though this design is for the older cells where the terminals are further to the middle. www.thingiverse.com/thing:4589040 I would really like to test this!

[@awo1fman]

The great thing about your battery shelf is that you have plenty of room to do whatever you want. If you want to periodically check and relieve the pressure, there's plenty of room for that. If you want to add straps or other kinds of clamps, there's room for that as well. So the design is perfect. The real question is what effect compression - or lack thereof - has on the function and life of the cells. Does compression help or hurt the health of the cells? The bus bars can always be modified or replaced if the change in length becomes too great, but it's the cells that you want to work well and last as long as possible.

[@VinceBadovinatz88]

Your comment sounds pretty logical

[@OffGridGarageAustralia]

Thanks Mark, great comment.

[@VinceBadovinatz88]

@@OffGridGarageAustralia I knew that was a good comment haha

[@Przedzik]

Always watch Your Chanel is so detailed and have this positive touch 😉. Why just why you don’t use flexible busbars from day one for me this should be mandatory 😩

[@OffGridGarageAustralia]

Well, flexible busbars are not necessary if you have a gap in between the cells.

[@patricklyons7683]

Sheet of white paper behind the batteries so you can shine flash light down the gap would be simpler.

[@JStarke240]

Compress them. Though, you've probably decided already. Good luck to ya.

[@djredix4358]

In den Datenblättern der Hersteller wird die Kompression immer empfohlen. Ich habe meine EVE Zellen auch gepresst und dazwischen dünne Korkplatten eingesetzt. Jetzt über 1 Jahr alt und keine Probleme. Schau die mal deine fertigen Batterieen (zb.QSO usw.) an. Die sind alle verpresst.

[@OffGridGarageAustralia]

Da ist ein Unterschied zwischen Compression und Fixation. Der Kork oder EVA Platten erlauben ja immer noch das die Zellen sich ausdehnen und zusammenziehen. Das kann ja nicht verhindert werden. Die fertigen Batterien sind meist verpresst, damit die Dinger nicht beim Transport rausfallen.

[@djredix4358]

@@OffGridGarageAustralia Hi. Alles klar. EVE empfiehlt jedoch im Datenblatt (LF280K) auch eine Verpressung alleine schon wegen der Zyklenzahl. Denke das es nicht schaden kann. Zerobrain hatte mal einen Spezialisten auf seinem Kanal der über LiFePo4 Zellen gesprochen hat. Sehr informativ dieses Video. Da wird auch über das Verpressen gesprochen, was es für Auswirkungen auf die Zellen hat und warum man das machen soll.

[@YanLipavsky]

Thanks for your educational videos - you rule SIR

[@diydsolar]

Hi Andy, HEAT IS ALSO IMPORTANT. let's think about cylindrical cells. They don't need it because a cylinder is more stable for expansion than a prismatic metal case. I have seen lots of cylindrical packs with gaps between them. As I say, heat is also important so a little gap is good. I don't think that 1 mm makes a big force in terminal, but, anyway, my conclusion is: "Not compress, but yes hold them. I will put the busbars as you have and then two cinchs to HOLD not to compress, one at up part and one at bottom. You leave gap to refrigeration and for expansion, and you don't let the busbar to get abnormal forces." That is my conclusion.

[@QuantumMarmalade]

normal usage heat usually won't make them buldge unless they are over volted.

[@diydsolar]

@@QuantumMarmalade My opinion is that if you hold them, that gap doesnt hurt and is good for refirgeration. may be not a big necesitity, but good, any way.

[@OurPalawanExperience]

I have both the LK280K, (New), and older (2016) Winston type plastic cased cells. My Winston type ae 200AH and were nstlled first. After a while the Winston began to expand, even though they are encased in hard thick plastic, So I compressed them all. No more issues of expansion to date. I would recommend compression due to the thin alumnium casing on the EVE type cells becasue at some point ...they do swell.

[@matthewknight5641]

You need to use rubber roofing material between each cell. Then clamp them together with all thread and plates or even wooden blocks.

[@OffGridGarageAustralia]

There are EVA sheets between the cells. This pretty ideal. off-grid-garage.com/electric-installation/

[@timevans8223]

EVE recommend compression to 12psi. They state that compressing them will give 1.6 times the life of uncompressed cells. Is so easy to do its not worth leaving them uncompressed in my opinion. There is no down side to compression

[@OffGridGarageAustralia]

The battery will degrade due to calendar age before any benefit of compression will give you an advantage. Unless you cycle it 3 times a day maybe.

[@timevans8223]

@Off-Grid Garage and what causes premature calender aging failure? Heat! Compress them and cool them. More life and reliability. You are only a year or so in and you have potential stud failure due to expansion. All this could have been avoided by compression. In addition you run batteries in a hot garage. At 35degC average you halve the battery life. At 45degC average you half it again. Heat plus no compression will lead to premature failure. Are you monitoring battery temperature?

[@malk6277]

Kudos to Andy for admitting and sharing his mistakes with us. My relatively uninformed take is: consider this build as a sacrifice on the altar of popular science and leave them uncompressed so you can keep monitoring how the batteries fare in form and performance over time.

[@OffGridGarageAustralia]

I think, the problem is not as bad as it looks like. Expansion cannot be avoided under any circumstances. I'm thinking of a different solution here...

[@RobbieHLM]

Maybe Andy did not make a mistake whatsoever. If you look for example at the Fortune cells (for industrial applications), the manufacturer provides cell holders that seperate the cells and leaves a gap between cells. Maybe for ventilation, maybe for a slight expansion. So maybe it will be perfectly fine to allow cells to expand a bit, as long as there is no stress on the terminals. As long as you don't go crazy high or crazy low and stay well below 1C, such a setup can last for more than a decade.

[@malk6277]

@@RobbieHLM "Maybe" is the operative word. I think Andy seemed like he felt he had made one - he spends a lot of time expressing a lot of concern at the outset of the video, and I remember from back in the earlier days of his channel he made a conscious choice to not follow the manufacturer's instructions on compression. Is their word gospel? Perhaps not, but humility would at least ask of us that we consider they may have had a more cogent reason to guide us that way, than the "maybe" we're relying on now to justify ignoring them. Yes, Andy's set up may well last a long time, but will it last as long as it would have had he compressed the cells? That's the question. That's the thing about manufacturer guidance: you might get away with not following it to the letter, but from their standpoint, they are dutifully passing on the conditions under which you stand the best chance of getting the performance they have rated their batteries for.

[@OffGridGarageAustralia]

@@malk6277 It will be in the next video...

[@republicridge5894]

Slot the battery buss bar! For future expansion.

[@OffGridGarageAustralia]

What??? No. That would be insane!

[@surplusdoctor]

@@OffGridGarageAustralia think about the top expanding, I used my own bussbars with 4mm studs on 105 AH Eve cells in a 48v configuration with 5mm drilled holes. Sitting on the shelf assembled in to a 16 cell battery the cells expanded as yours did. The top studs are now egg shaped. I looked at the factory buss bars and they have an oval opening, for this expansion. I do not use nuts to be tightened with a wrench. I use finger tight nuts knurling so as to not over tighten but yet get very good contact. if the data I present is crazy to you, CONTACT THE MANUFACTURER. Lets see if I am correct.

[@mikedurham4448]

as i pointed out yr or 2 ag0 ...lol... thermal and chemical expansion (mechanical) will slowly expand contract the terminals every cycle ... and eventually disrupt the circuit effectiveness.. block wood each side and use steel bands to stop any more movement .. neat and means u do not have to dismantle and affect what is already running fine ... smiles .. if the bars were flexible less tension on terminals with expansion ... but thqat is another method . this is where we r ...gppd luk and always keep this beerwah boy smiling ... keep up the excellent effort and anaysis. cheers big ears !

[@scoobyblu5815]

You did say from the beginning you need compression you can't just leave them sitting on a shelf, many people make this mistake good to see that you're showing them what really happens if you don't. The fancy lights don't help at all , compression mate !

[@OffGridGarageAustralia]

Nope, no compression. It's called fixture and is what Seplos does in their battery box. Swelling will always happen.

[@daolinhai]

Dont worry too much. You yourself explained very well, why you do not compress them. The reasons are still there and same. Just move on to those flexible busbars and let the cells alone. I construct my batterys right now, first bank of 16 cells done, 2. bank over the weekend, testing not done so far and I'll not compress them, too. If they do just 3000 cycles, they will last 15 years. They pay themself within just 1200 cycles at our power costs here, so that is calculated for 6 years. Really? If you want to compress, you need to use some feathers with constant pressure, to not overcompress the cells, like some people do with solid steel bars. Thas can easily destroy the cells, cause the pressure gets far too high in a bank of 8 (or in my case 16 cells) in a row. Expansion is about 1 mm each cell within soc 0-100%. You can not force the cells to stay in perfect quadric shape without destroying them internally.

[@OffGridGarageAustralia]

Thank you. All the best with your built, hope all goes well.

[@longdistancerider691]

You may be able to use your aluminum wand with a hard isolate. then you have more space on the other side.

[@john_in_phoenix]

I vote you leave them as is, just so I can see what happens in another year. Mine are very lightly compressed, and of course where the jelly roll wraps internally they have expanded a bit. No big deal, just keep any expansion from affecting the terminal connections. The swelling so far is perfectly normal, just don't over charge them. I am not taking mine above 3.45v except maybe once a year.

[@peledeng1909]

what a really dumb reply.

[@OffGridGarageAustralia]

Yes, I do the same, 3.45V is the max for mine. This bit of expansion is normal and even happens under compression.

[@vinniec5286]

Why compress the batteries? Leave a slight gap for airflow/cooling.

[@OffGridGarageAustralia]

Yes

[@KevIsOffGrid]

for testing one pack should have been compressed from the start, just to be different and a direct comparison. However doubt it makes any difference, so do not worry. I have challenged my solar array to make more power in a day then yours, 2kw vs 14kw ... but as I get to sunnier and sunnier days (2 x 8kwh days recently) and you are having some lower power days - as low as 14kw; then I think a day when you do under 10kwh and I get 10kwh is possible if I get sun in mid summer when you get rain :)