Why you should compress your LiFePO4 battery! And why it does not matter... 🤷‍♂️

Рет қаралды 61,559

Жыл бұрын

I know, I know... the oldest question since the invention of lithium batteries again: should you compress or should you not compress your cells?
To answer this question, I have here some information form a battery expert which I explain very detailed in this video. Mainly, there is only one reason to compress your cells. And this only for a certain amount of time.
Well, who would have thought that the actual reason so many people compress, has nothing to do with extending the life of the batteries.
All information here in this video...
Dominik's KZfaq Channel, @Zerobrain: LiFePO4 - ALLES und noch viel mehr über Lithium Akkus: • LiFePO4 - ALLES und no...
Why compression will not extend battery life (something else kills your battery): • Why compression will n...
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Пікірлер: 502

@tiredofeverythingnew Жыл бұрын

In this video, host Andy discusses the topic of battery compression for lithium iron phosphate cells, explaining the reasons behind compressing cells and why it sometimes doesn't matter. The video focuses on the insights from Marcus, a battery expert who has studied electrode materials in lithium batteries. Marcus explains that compressing cells is not meant to prevent swelling and delamination, as this occurs on an atomic level and cannot be stopped by any amount of force. The actual reason for compressing cells is to squeeze out tiny gas bubbles that arise from the porous material inside the cell during the first few charging cycles. This helps improve the battery's overall performance and longevity. However, Andy also emphasizes that compression might not matter in certain cases, such as when cells are purchased from resellers who haven't compressed them during testing. In these cases, the damage has already been done and compressing them later on would not make a difference in the lifetime of the batteries.

@OffGridGarageAustralia Жыл бұрын

Jeeeez, I should copy and past this in my description of the video... Or use it as a script for a 1min long video instead of 12min 🤔

@J_i_m_ Жыл бұрын

@@OffGridGarageAustralia Just ask ChatGPT to summarize your video (provide it the youtube transcript or use a plugin) and you get exactly that description.

@AndreaMastrilli Жыл бұрын

@@OffGridGarageAustralia used gocharlie

@faded.0913 Жыл бұрын

So you're saying that even if I compress my cells they could still possibly become bloated enough to cause an air gap if pushed too hard?

@volodymyrzakolodyazhny7740 8 ай бұрын

Thank you for compacting it, you saved me several minutes.

@hummmingbear Жыл бұрын

I gave my cells a big hug when I got them and hopefully that squeezed out all the bubbles. I compress them with my love.

@jetfu400 Жыл бұрын

What the hell man 😂

@OffGridGarageAustralia Жыл бұрын

That's the way, Brian. Great!

@frankbierschneider8785 Жыл бұрын

😅😅😅❤

@FutureSystem738 Жыл бұрын

I did the same, you’re not alone!

@powerofone1645 25 күн бұрын

Too much love and they'll explode.

@Eulhofer 9 ай бұрын

"Der Drops ist gelutscht" - so nice.... Thank you and many greeting from rainy and cold germany, Wolfgang

@user-pi1uz2zj7i Жыл бұрын

Two possible scenarios I think a fixture (not necessarily compression) could be a good thing. I built two 48v batteries 1 year ago, one of them is installed in my boat - I wanted to minimise damage caused by vibration. The other battery is running my house. The key thing here I used flexible bus bars on both batteries between all cells to allow small movement due to vibration and swelling. I was more concerned about any movement damaging the cell terminals / electrodes.

@LaBamba690 13 күн бұрын

If the bus bars are long enough, there will be a gap between the cells and therefore, the tiny swelling will not cause the cells to touch each other or apply any force on the terminals. So flexible bus bars aren't necessary in that case. And as Andy said, it's good to have some space between cells for ventilation to keep their temperature lower - assuming the load current is high enough to raise their temperature significantly enough to need the ventilation.

@aday1637 Жыл бұрын

When I built mine 1-1/2 years ago, I used your recommendations regarding compression (none). I was getting nervous after your recent vids. Glad you sorted this out for us.

@OffGridGarageAustralia Жыл бұрын

I did a lot of research when I build mine back then but information were rare. We're a bit better situated these days and have more information and also experience on hand.

@RolandOfGileadOnYT Жыл бұрын

@@OffGridGarageAustralia what about 'overcompressing'? Does that exist? Or will the compressing wood/steel/etc, still expand a little?

@VinceBadovinatz88 Жыл бұрын

@@OffGridGarageAustralia I think your newest thought about the compression sounds very logical. I imagine it's very correct. With all the practice you have now and all the extra knowledge in the world about it.😊

@markusb69 Жыл бұрын

@RolandOfGileadOnYT Hi Roland, Markus here ;) . First of all thanks to Andy. Never thought about becoming that kind of "famous" with lauching Dominik's video :DD. Regarding your concerns about some kind of overpressure - Yes it is possible, but not with usual or non-professional tools. I have to explain it in detail: There are two sorts of expansion: The cyclic one while charging and discharging and the irreversible one caused by the effect of loosen electrode material. As I explained in that video, electrodes are compacted by calandering to increase volumetric capacity with a higher density. Especially during the first cycles the electrode is still in original shape and the expansion is caused by the intercalation of Lithium-Atoms into the Graphite-Layers. This expansion cannot being stopped. If you think about that all pairs of electrodes have a thin layer of separator between cathode and anode and this separator usually is made from a stretched foil of Polyethylene / Polypropylene you can imagine what´s the weaker part.... It´s the separator. So if you press that batttery with very very high forces and hold it constant to this distance with 100% stiffness, the force increases enormously while charging and the expansion of the anode raises until the anode penetrates or even pierce through the separator which which therafter will destroy the battery.

@RolandOfGileadOnYT Жыл бұрын

@@markusb69 Hello Markus, thank you for your answer. I was asking, because someone at the DIY Solar Forum asked about this, he had the impression he compressed the cells to the point where the (short) side of the case buckeled inwards ever so slightly. I myself have a battery with plywood on both ends and threaded rods, and compressed/locked the cells in place (there's a insulation between cells), until I couldn't move the cells anymore. Afterwards, I wondered if I should have made the blue cell wrapping somewhat less slippery first, so the cells would be fixed in place with somewhat less force. The corners of the case still don't touch eachother. But from reading your answer, I'll take it that as long as you don't truely crush the aluminum casing, you should be fine, cause the stuff we use to hold the cells won't be strong enough to withstand the forces that cause this minor expansion during cycling?

@Zerobrain Жыл бұрын

Great Video! I especially liked the part that you watched the my video several times ;-)

@OffGridGarageAustralia Жыл бұрын

Here is the man himself. Thanks for the video and information. It was a great show!

@landonashby2029 Жыл бұрын

I Compress my cells for one reason...ease of handling. I do this with 12v 4 cell builds. I use the compressed cell battery in small mobile setups. I use 4" electrical tape to do this and makes the cells easy to handle like the format of a lead acid car battery. 😊

@ralfkremer8882 Жыл бұрын

Hey Andy, great you used that fantastic Interview video. What is missing now is the aspect of connecting the cells. Bus bars are rigid whereas cables connect the cells in a flexible way and can compensate the breathing of the cells …

@waldemarfrank7546 Жыл бұрын

Danke Andy für kurze und gute Erklärung. Dann bin ich auch beruhigt und werde an meinen akkus nichts ändern und mir keinen Kopf zerbrechen. Top Videos mach weiter so.

@CarstenSaager Жыл бұрын

One obvious benefit from compression is that you fix the whole assembly to avoid stress on the busbars,and you are right,for this you don't need much force, the assembled batteries in a PE casing does the job

@gg-gn3re 6 ай бұрын

yea he didn't even mention it. But the bus bars don't matter, the things they are connected to do (anode/cathode terminals) If you build the batteries directly touching and straight bus bars it'll damage the anode and cathode terminals. best is the leave a say.. 2mm gap between the cells or something if you aren't going to put something between it. at least they will last then

@Tech4UbyJames Жыл бұрын

I love how people get so beside themselves because we don't do what they think we should do. Andy you do you! And if no one likes it oh well. I love ya!!! Keep doing you!!!

@OffGridGarageAustralia Жыл бұрын

Love you, bud! 😉

@VladBYT Жыл бұрын

Hello ! I have started to build my own 12v battery after I have seen all your videos from the beginning until now. It is a small project but I am learning. Congratulations for all your good work and good advices! You are the best !

@lightitrun5209 Жыл бұрын

Thanks Andy. Another great, informative video. We just can't stop learning from you. What are we going to do if/when a new battery chemistry is introduced? Can't wait! Fun fun fun or spat spat spat😊

@OffGridGarageAustralia Жыл бұрын

Learning will never stop for us, I guess. Oh a new chemistry??? What may that be?

@M-Clem Жыл бұрын

Nickel-Iron battery ?

@OffGridGarageAustralia Жыл бұрын

@@M-Clem Can you buy single cells already or is this still future?

@mikemcguire5859 Жыл бұрын

Thanks for clearing up all that information.

@davidpatrick1813 Жыл бұрын

Thank you for helping my upstairs to function better... good research and reporting.

@malk6277 Жыл бұрын

Thanks Andy - between this video and the other one you linked to, you've laid out a lot of great info. I can now see how compression won't make a difference in my use case!

@jamieandrews3238 Жыл бұрын

Andy thank you for this video! It has really helped. I was getting so much contradicting information and was just confusing. This is a really solid explanation

@j.j.alexander9542 Жыл бұрын

Thank you for the information. Exceptionally well explained.

@user-sm3xq5ob5d Жыл бұрын

Congrats! Your are the first I watch who has gotten it and explained it in a very clear way. Remains the question what would have happened to your "certified" cells which spread apart. I think it helps to keep the cells in check so no readjustment of solid bars is necessary. If you have flexible busbars then it might not matter. So there might be a mechanical advantage to apply some pressure to the cells.

@user-sm3xq5ob5d Жыл бұрын

I developed a way to administer the right amount of compression to the cells with my cordless screwdriver. I didn't want to buy another tool (torque wrench) which I would use only one time. So I thought about the screwdriver I already own because its torque can be adjusted. Albeit with no calibrated settings. To find the right setting I used bathroom scales and a lever. The lever was attached to a board at one end with a long screw. Halfways I made a hole in the lever and the board through which I put the actual threaded rod I want to use on the battery. The far end got a short screw which pressed on the scale. So I had a 1:2 ratio of the middle and the end forces. The 300kgf on the battery cells will be achieved by four tensioning rods. So a single rod has to produce 75kgf of pull. On my setup if the 75kgf have been reached at the middle of the lever the scale would show 32.5kg. I let the cordless screwdriver tighten the nut on the rod until the scale showed 30kg. Then I turned the clutch setting back until it clicked (released) at that scale reading. I marked the setting and that gave me the torque wrench setting I need.

@achimxe2617 Жыл бұрын

Thank you for the great in depth knowledge about batteries!

@markmac9515 Жыл бұрын

Very good explanation, thanks.

@edwardvanhazendonk Жыл бұрын

Thanks for sharing Andy, now I have another channel to watch as well 🤔, you made good points. I think I like your option of spacing between cells as your busbars won't get tense by the expansion of cells. Keep the sunny side up down under!

@jdbrinton 10 ай бұрын

Finally, a definitive answer on this subject. Thank you so much!!

@JR-kk6ce Жыл бұрын

Almost two years ago I had a translated conversation in China with a CATL rep. I was told that the main enemy of Lifepo4 cells is moisture, and that a deep vacuum is applied to the cells prior to sealing in order to convert any moisture into a gas, remove as much moisture as possible, and that any remaining moisture in gas form was not expected to cause damage The compression I was told was to help maintain cell vacuum and keep any moisture present, no matter how little, in gas form where it will cause no damage. So, now I have even more questions. Actually, questions upon questions which lead to even more questions. Given that spent time is the only thing which we can never recover, I'm ready to move on.

@FutureSystem738 Жыл бұрын

Yeah- I’m sure we will know a lot more about these cells in thirty years time. Problem is: I won’t still be here 😅 It’s all still fascinating though, great stuff and great research and testing by Andy. At least my seven plus years old LFP Winston cells are still awesome.

@vastirvision 16 күн бұрын

@@FutureSystem738 I realize that this is an old comment, but on the off chance that you may see this and reply: I have been highly interested in these Winston cells, yet I have been unable to find much info on them in terms of real world experience. You have that, so if you might kindly answer a couple of questions I'd be greatly appreciative: 1) In what application are you using the Winston cells (ESS, EV, mobile/marine, etc.)? 2) What size cells do you have? What is your pack voltage, and in what configuration are they assembled (i.e. 16s1p, 8s3p) What really intrigues me about them is the manufacturer's claim that the Winston batteries, due to the yttrium, can be safely charged in low temp environments that far exceed that of a typical LFP battery. Any info you can offer is greatly appreciated. Thanks in advance!

@FutureSystem738 16 күн бұрын

@@vastirvision My Winston cells are 400Ah cells in just a 4s (ie: 12v) configuration in my large caravan. I built the pack at the beginning of 2016, and for many years operated them without any kind of BMS, just keeping a bit of an eye on balance with individual cell voltage monitoring, and using very conservative voltages to avoid any chance of a cell going high, and typically 13.8v top of charge = 3.45v/cell. (They’re bolted in to the caravan under some degree of compression.) I actually manually balanced them slightly maybe about three?? times. Then I added a JK BMS a year or so ago, which keeps them extremely well balanced, usually to within 2 millivolts, and as a result I upped the top of charge to 14v = 3.5v per cell. Although I have never FULLY capacity tested them since installing, I often discharge to about 20% and have noticed no capacity loss since the beginning of 2016. I have about 1kW of solar, and we use them for everything including hot water, fridge, induction cooker, microwave, and even some airconditioner use (heating and cooling) when solar conditions are good. If the weather is not so good, we revert to using some LPG for hot water and cooking to reduce electrical demands. I was not aware of any claims about charging at lower temps- have always avoided any charging if they’re close to 0 Celsius.

@gumpster6 Жыл бұрын

Great breakdown on this issue where nobody could really give a clear answer. Happy to see it put to rest.

@imag555 Жыл бұрын

Thanks again Andy! Great information always

@OffGridGarageAustralia Жыл бұрын

Thanks Joe!

@AveRage_Joe Жыл бұрын

Great information Andy! Love it and thank you for sharing!!! I have not heard some of that! You are 100% correct how some of those places test there 1000 cells at a time. I was sent a similar video and pictures when I purchased mine lol. I would like to add one benefit of compressing or fixing a group of cells. The accidental or unintentional overcharging of a cell or cells from a faulty bms or whatever the reason. You can prevent the pack from making a smiley face😀which may help from damaging other cells and depending on the area the cells are in could prevent damage to other equipment. Dont mind me, I over think EVERYTHING!! 🙄

@matthewknight5641 Жыл бұрын

Andy... i dont have a lot of money and i just received my first 8 lifepo4 and the other 8 should be here in a few days. Im building a 560 ah eve battery with grade a cells. I need my batteries to last as long as possible and i appreciate the work you do and all the videos. Hopefully they last a long time and give me and the wife years of off grid life.

@dieselbstversorgerfamilie Жыл бұрын

Thank you so much for your informations aboute compress cells or not. My research has revealed the same. And thank you for your very informative videos! Greetings from Sweden...

@OffGridGarageAustralia Жыл бұрын

Thanks for your feedback and hello to beautiful Sweden 👋

@dennydewaal137 Жыл бұрын

🤔brilliantly solved Andy

@tryingtosucceed Жыл бұрын

Hi, I bought some 20 year old winston thundersky 60ah, Capacity is 50ah, so calendar ageing is pretty slow, they were factory compressed in 3 cell packs.

@OffGridGarageAustralia Жыл бұрын

Great, hope they will still last for a while...

@FutureSystem738 Жыл бұрын

Great one Andy, answers a LOT of questions. We’re all still learning about these cells, and probably will still be in 30 years, (though based on family history I won’t be here then.) However in the meantime, I’m still planning to be here anyway. Maybe I can beat the odds, and maybe my batteries will also still be going. 😁

@garysmith9080 Жыл бұрын

Great practical stuff once again

@Flowing23 Жыл бұрын

Excellent excellent information. Very valuable, thank you very much.

@OffGridGarageAustralia Жыл бұрын

Thanks Rob. Thought it would be interesting to extract these info from this video and share it.

@spiritseer001 Жыл бұрын

Keep it up brother! Very informative video! ❤

@wallneo7800 Жыл бұрын

Hey Andy, danke für deine informativen Videos! Hier kann man wirklich einiges für seine eigene PV Anlage mitnehmen. Weiter so! 💯

@digital-experiance2390 Жыл бұрын

Bitte nicht auf den Blödsinn von Andy hören. Der verbreitet so viel falsches, nur um Klicks zu bekommen. Es gibt sehr viele gute Gründe, die Zellen mit Kompression einzubauen. Andy hat leider wenig davon verstanden. Aber dies ist ja bei seinen Videos üblich. Jeder lernt, manche eben nur mit Try-n-error...

@dahuar2006 7 ай бұрын

Great explanation. Thank you!

@uweknofel9149 Жыл бұрын

Apart from the arguments regarding cycle and aging of the cells, would not compressing (eg fixing ) them make sense to keep the busbars in position ? Or is it actually the other way round, always leave a bit space between the cells for the ‚swelling‘ so that there is no impact on the busbars ? ( not a option in campers / boats )

@electro2606 Жыл бұрын

The bus bars have space in them like 4-5 mm

@marlomontanaro3233 Жыл бұрын

Like Andy said, you cannot stop the expansion. Nothing on this earth can stop the expansion. So, something has to give! If the cells are compressed, I think you do more damage to the battery terminals under a tremendous amount of physical stress.

@TheRonskiman Жыл бұрын

@@marlomontanaro3233 not if you've got flexible bus burs.

@RJ-cc1fz Жыл бұрын

Flexible busbars hands down

@OffGridGarageAustralia Жыл бұрын

I guess, either flexibles bars or space in between the cells to prevent any force on the terminals. Both🤔

@camielkotte Жыл бұрын

Thank you. I did not compress and run an oven on my 24v system at .5c and the cells are happy. Not that much swell but all is well.

@OffGridGarageAustralia Жыл бұрын

Not that much swell but all is well. 😂

@HC4L666 Жыл бұрын

Great Info Andy !!

@OffGridGarageAustralia Жыл бұрын

Thanks Steven.

@boatelectricaldiy Жыл бұрын

Another great video, one of your best Andy. Fixture IS important, but no, you don't have to do it. Cycle life might not be important in your high capacity installation, but most DIY installations are on a budget, and cycle way more then you do. My marine customers usually do a 600AH 12vdc installation that gets a full cycle every day or two. These installations average 250 to 300 cycles a year for my commercial customers that recharge with a diesel generator or shore power (no solar). You brought up something I'm pretty sure I failed to mention in my previous explanations. The cells do in fact swell and compress. Like I motioned in previous comments, the major swelling you've experienced is avoidable with a fixture, it's why I said that cells should only be removed when empty. The level of swelling you've experienced is completely avoidable. As for your statement that cells won't be damaged by compressing after they have severe swelling, my friend I encourage you to do so and see for yourself the fluid flowing out of the seal( It will make a great video =). Fluid breaking though the seal is damage. The question then becomes, how much damage can be done before cell capacity is affected? I personally have have not been willing to push past the seal breaking point after doing it the first time. If you flatten them until they are as flat as new cells will they burst and compromise the vacuum? inquiring minds want to know. Lets see that video Andy! For Science!!1

@FutureSystem738 Жыл бұрын

Wow, yes, that would make a great video! 😮 I have Winston cells in my RV that I assembled with significant compression, and flexible Busbars. To my knowledge they’re still virtually as good as new. Although I haven’t disassembled the pack (big job in a tight space!), nor done a full scientific capacity test, I have noticed zero problems with daily use and the occasional deeper discharge, and they are still absolutely fabulous. I also have a friend who has “abused” his a lot more than me, with some low voltage AND high voltage “excursions”, with no BMS. They’re also still fine.

@wayne8113 Жыл бұрын

Thanks Andy

@domotica_solar Жыл бұрын

Congratulations for the video...great information and great show 😉

@OneStepToEscape Жыл бұрын

Thank you, Andy! Especially for the Markus video link

@HalilKacmaz-dq1bc Ай бұрын

And whether you compress your cells or not, we always love you Andy

@OffGridGarageAustralia Ай бұрын

I love you too, my friend!💖

@Oleg_John 4 ай бұрын

An NKON company representative recommends compression. I don't think it can get any worse. Or better yet, questionable. I do the compression with two metal plates and four 8mm studs. Self-soothing is a great thing! Thank you for the video. Oleg, Ukraine.

@ToddDesiato Жыл бұрын

Brilliant, Andy! We should discuss Warp Drive someday. I think your insights would be valued. I hope you enjoyed the beer!

@HarrisRanch Жыл бұрын

Awesome information. The beer is on me! Cheers😀

@lickalittle Жыл бұрын

Excellent research 👏 B-

@nn858121q Жыл бұрын

its so Andy !! Thanks

@carmichaelmoritz8662 Жыл бұрын

I've only ever purchased use cells. I hope you still love me 🤣😂🤣👍🤟👌

@OffGridGarageAustralia Жыл бұрын

Absolutely! ❤

@dongjuang4196 8 ай бұрын

Thanks for information!

@Christian76S Жыл бұрын

Thanks for picking this up Andy

@OffGridGarageAustralia Жыл бұрын

This topic pops up again and again.

@alexsimmons1803 Жыл бұрын

Some level of battery fixing to assist prevent/reduce stress on terminals is probably worthwhile though. Or flexible busbars.

@eagleray1 Жыл бұрын

Agreed, although based upon Digital Mermaid's heat tests of rigid vs. flexible bus bars, I think the verdict is in that flexible is better all around if you're willing to put the work in to construct them.

@alexsimmons1803 Жыл бұрын

@@paul_dz Which requires customising busbars rather than using the standard ones supplied.

@Michael-AUS Жыл бұрын

But, what about the cell terminals? If the expansion pushes the cells apart by even 5mm per cell, won't that mean that a row of 8 cells has the potential to expand by around 40mm in total? Busbars with with low tolerances might therefore cause pressure on the cell terminals and damage them as a result. I think light compression (using Kapton tape perhaps) could help in this regard. It also helps keep the battery together in the event of an earthquake too. 😉 Love your show btw.

@svn5669 Жыл бұрын

Thank you ! Clear !

@Juergen_Miessmer Жыл бұрын

Danke! You made my day ! 👍👍👍👍👍👍👍👍👍👍👍 I hug my cells carefully.

@OffGridGarageAustralia Жыл бұрын

Thanks a lot Juergen, appreciate your support!

@keyem4504 Жыл бұрын

That's been really interesting. Thanks for sharing. Any we have to understand, that when that another of cycles the batteries are still at 80%. No reason to throw them away if you ask me. And I love you too, Andy😘

@jovanhouten9050 Жыл бұрын

Great video. Thanks for sorting that one out. However.…., You still might want to “compress” your batterie cells for mechanical reasons. Assuming that some stationary batteries are going to be moved around, especially by DIYers, a form of mechanical fixing might be a good idea. Packed with EVA foam in between the cells, EVA foam will compress as the battery cells expand. The cells will more likely maintain their position and this will reduce the stress on the busbars and terminals.

@dirk_p Жыл бұрын

Der Drobs ist gelutscht hat mir gefallen 😂 thanks again for the valuable knowledge

@OffGridGarageAustralia Жыл бұрын

Thanks, Dirk!

@ML-hf6ii 2 ай бұрын

one of not so many channels that really deserves subscription

@MrBigbela 3 ай бұрын

Thank you!

@airgead5391 Жыл бұрын

Excellent!

@dazrichie897 Жыл бұрын

Thankyou for confirming... IT DOESN'T MATTER!! 😅😅🎉

@dor642 Жыл бұрын

Vielen Dank, well explained 👍

@ffh.linared Жыл бұрын

Fantastic video. 👏🏼👏🏼👏🏼👏🏼👏🏼👏🏼👏🏼 Thanks!

@donmcleod8307 9 ай бұрын

Brilliant. Thank you

@bossveendam Ай бұрын

Thanks for this insight, Andy! Will check out Markus' story also!

@TheRonskiman Жыл бұрын

Interesting video. Good job that my compressed cells are EVE grade a cells, from a supplier I trust. I also didn't test or charge them until they were compressed. Mine are cycled every day or two.

@calvinflager4457 6 ай бұрын

Another THANK YOU.

@wideawaketotruth5301 Жыл бұрын

Wow, another informative video.

@OffGridGarageAustralia Жыл бұрын

Thanks!

Жыл бұрын

Personal experiment over a three year span: LiPo cells not lifepo4 but close enough for the comparation. The packs consisted of six 8Ah cells. There were two packs. All exterior (outer) cells swollen with age and gentle, much below specifications. Cells were specified to run from 3.5v to 4.20v at 15C. I used them within the voltage range, strictly, and peak currents were below 4C, mostly below 1C. All four cells that were on the outside of the packs are swollen, lost their capacity beyond usefulness but the interior remaining cells that were kept compressed inside are still above 80% capacity and not swollen.

@user-ww6jb5cd2p 4 ай бұрын

Thanks for the information !!!!!! stay safe sir

@TrevorFraserAU Жыл бұрын

Once again, my knowledge has grown ten fold! You are dishing out gold nuggets free! Think it is time for another round of S.P.A.T. sponsorship!

@rosmisha 8 ай бұрын

Great and powerful research! Greetings from Ukraine, I am just getting ready for winter shutdowns and will build my lifepo4 battery. Your videos help me a lot with this

@OffGridGarageAustralia 8 ай бұрын

You should have all the info here on the channel. Take care!

@Jonyys Жыл бұрын

the end is good 😁

@OffGridGarageAustralia Жыл бұрын

Love you all 😁

@5885ronny Жыл бұрын

Danke fürs Video 👍👌

@carlh2007 Жыл бұрын

Thanks Andy for the reassurance on my decision not to compress for my 12v 280ah pack I made. I cycle it aprox 12 times per year so it will make 0 difference for me.

@brianscally3439 Жыл бұрын

well done Andy! I retain my cells, which looks a lot like compression, because I my solar cells are mobile. and shaky moving cells is bad. I think this is a valid case.

@stevenfrazier8939 Жыл бұрын

Good Job

@fldutch Жыл бұрын

Thx for the video. I built a clamp for initial testing my cells after reading that manual - not made of out metal, but out of "18mm Siebdruckplatte", and i do not exactly compress to 300kg. Well - first cell of eight i tested without that clamp, all the other cells with clamp. And i have to admit: the first cell got a little more bloated then the others - not really exactly measured it, but you could see the slight difference. Cells were nearly perfectly flat before testing (EVE LF280K Grade A Cells from NKON). Well another aspect: when you compress flat cells with a force of 300kg and cells will expand anyway (on that atomic level), the pressure might rise above 300kg leading to damaging the cells 🤔? Not sure about that, so i do compress my cells a little using a compressed sturdy closed foam piece that can expand when pressures rises. The video is definetly worth watching - and stills leaves some unanswered question :). I'm curious when there will be a followup.

@marcoarpago Жыл бұрын

Thank you Andy fantastic video :) very very helpfull

@ThePuddingham 6 ай бұрын

Firstly; thanks for your fantastic input (output?) Andy…. Secondly; I’m trying to commission (!) a 16S set of 340Ah cells before Xmas and struggling to see see through the miasma! I am now a bit more relaxed about it but there is one thing that strikes me: How does one apply 300kg of force to a battery pack?!?!?! Mine are envisaged to be organised in two rows of 8. That’s therefore 600kg over the two faces. Incredible! I had decided to use threaded bars in conjunction with flat plates of currently unknown dimension and material and spring load the bars with old engine valve springs, to prevent exponential pressure changes as the cells wax and wane, but now I’m not convinced that my springs are man enough.

@fabiant.3628 Жыл бұрын

Danke!

@Oleg_John 4 ай бұрын

Представитель компании NKON рекомендует компрессию. Я не думаю, что может быть хуже. Или, что еще лучше, сомнительный. Я делаю компрессию с помощью двух металлических пластин и четырех 8-миллиметровых шпилек. Самоуспокоение - это здорово! Спасибо за видео. Олег, Украина.

@ivoscuka8537 Жыл бұрын

I just checked my Victron Connect BMV-700 [Google -> Upgrade ostrovní elektrárny 12-36kW, LiFePo4]. It let me know, that for the last 16 months (Jan-2022 I installed BMV-700) I did 13 total charge cycles. So in my case, for 2500 cycles I have to charge/discharge my cells for 256 years. Well I am fine with these numbers.😀. Thank you Andy, you are great!

@danfitzpatrick4112 Жыл бұрын

Great stuff! For me now... what becomes more of a concern when putting together a battery bank? I'm thinking that a solid connection (Bus bar) between positive and negative between each battery could be a point of failure over time, as the natural expansion and contraction happens with the cells and pulls on the terminals of the battery. I believe that a space between the cells to begin with should be a good start, then using an expandable electrical connection between the posts should be even better. (Like what maddie the mermaid uses). 🍻

@danfitzpatrick4112 Жыл бұрын

@@davidb.5544 Yes, those would be great as well!

@RJ-cc1fz Жыл бұрын

Compression prevents unnecessary expansion. Yes some expansion is not able to be prevented. Excess unnecessary expansion can cause delamination. I use springs to keep the cells constantly close to the proper compression. Overcharging or overdischarging causes delamination. Proper compression can stop excess expansion during those mistakes. That’s why the manufacturers of the cells recommend a specific pressure

@OffGridGarageAustralia Жыл бұрын

Dan, also what will happen in batteries which have welded busbars (QSO for example)...?

@danfitzpatrick4112 Жыл бұрын

@@OffGridGarageAustralia Right!, Good point!

@onthelake9554 Жыл бұрын

@@OffGridGarageAustralia Just about all welded bus bars I have seen have had the hump in the middle and the cells have been in a fixture .

@beranr Жыл бұрын

Díky!

@TheCrozenfox Жыл бұрын

Put your cell on a vibrator and any bubbles that are stuck will rise to the top 😁 Like the needle vibrator for the concrete used to remove the bubbles inside the concrete. I'm pretty sure, none thinked about that.

@OffGridGarageAustralia Жыл бұрын

Yeah, the expert said it would need a vacuum and around 400°C to remove them all but at these high temperatures the separators (PP material) will not survive.

@chrysM34 Жыл бұрын

Thank you !!!

@Remigius0815 Жыл бұрын

Best channel on KZfaq ✅

@OffGridGarageAustralia Жыл бұрын

Thanks again, MrHuber!

@lomsi1 8 ай бұрын

Brilliant !! Could also be titled " The debate around A & B grade cells...and why it doesn't matter". A suggestion for follow on video. What things really matter for a long lifetime from you LPF batteries..

@petervandeburgt7414 Жыл бұрын

Thanks Andy. I am though, going to replace the busbars with flexible cable and lugs as I do believe that there is stress on those terminals. And I dont think that will do any battery any good. Luv ya effort.

@daolinhai Жыл бұрын

I‘ll not use compression at all. The cells will survive or not. I have seen compressed cells exploded for improper charging. That is the thing to be aware of. Some ppl do not see the bms as a part of the battery and put a breaker in the wrong place or dont use a bms at all, what will kill some cells of the pack sooner or later. My awareness will be temperature in wintertime, my battery place is an unisolated shelf outside the house, so I‘ll isolate the batteries and put some heating elements inside, to keep the cells above 5 Celsius. Thanks for your video. We are the rare ones without compression. And what I see in many videos, they do compression without feathers, so its wrong and the force rises while charging and that is a lot.. better no compression than wrong compression.

@OffGridandOutdoors Жыл бұрын

But you didn't mention anything about terminal stress. Your batteries in their swelled state appeared to be put some stress on the terminals. Also I've had my Eve 230 cells compressed since I bought them 18 months ago and I will take them apart again this weekend to check with a straight metal ruler for swelling. But I did not see any last weekend when I had them apart for reconfiguration

@touqeershah7563 8 ай бұрын

Great great great..... Thnx a lot

@r3tr0nic 10 ай бұрын

From a CATL datasheet : "The cell will generate swelling force during attenuation. The swelling force of the cell at 60% SOH under the test condition of 15mm steel plate, which is about 40000N. The customer needs to consider the reliability of structural strength in the product design process." I'd say yeah, that is heaps of force. If I did the maths right, thats 1100kPa or 160PSI. Likely more since I used the entire surface area of the side of the cell (280AH) since it was not indicated. Kind of crazy. Looking at the construction of various batteries (from those with no compression, to those with squishy foam pad things, to those banded with steel and heavy steel plates at each end) I reckon I really like the idea of squishy rubber padding between the cells, with some compression from either steel banding or threaded rods. Gives some pressure, but has give too. Only time will tell, for first hand experience for me. I've only just gotten into the LiFePO4 game.

@chrispaul7401 Жыл бұрын

As others have said, the movement of uncompressed cells can cause stress on the terminals. I setup 16 eve 280 cells uncompressed and after about 20 cycles the noticeable swelling on about half the cells (interestingly it was not even) was pushing the bottom of the cells apart due to the clamping force on the terminal. They are now clamped with braided bars! Separately, Mine do one full cycle per day. If uncompressed means I only get 2500 cycles, that is under the 10year calendar life and crosses over to the point where compression could extend the useful life????

@mikesmallwood8299 Ай бұрын

There are three major factors that lead to premature cycle life. I think the order is as follows, from most important to least important. 1) Thermal, over 30-35°C can cut a batteries storage life to 1/6th its potential calander life. 2) DoD and Rate of C. 3) Bubble Saturation due to lack of initial compression. Why thermal matters. 18 years storage at 30°C vs. 3 years and change for 40°C storage. So an optimization test would be interesting, taking into account #1 thermal, with respect to adjacent clamped batteries heating and raising the ambient temperatures amongst the batteries over 35°C. Testing a pre degassed/clamped group. Clamped and not clamped with the not clamped spread out as to not transfer heat to one another. See if this has any further optimization for cycle life. Will pre degassing/clamping coupled with post degassing to well separated cells for ambient room cooling between the batteries lead to a greater cycle life over a continually clamped bank? A continually clamped bank may transfer heat between batteries leading to a premature cycle life loss vs. A post degassing unclamped, spread out and left to cool between them during use.