How LiFePO4 Batteries Work and The Truths About Compressing Raw Cells

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  • Опубліковано 11 лис 2024

КОМЕНТАРІ • 177

  • @josephcagiano3055
    @josephcagiano3055 3 роки тому +9

    So glad I found your channel today. Been binge watching all night. Already you’re channel is my favorite. Can’t even describe how grateful I am for the amount of information I’ve obtained from you. Your channel is so high quality you should be at 1,000,000 subs in short order. I’ll be sending every RV enthusiast I meet your way. 🤙🏻

    • @freelyroaming
      @freelyroaming  3 роки тому

      Wow I am very flattered! Thank you so much 🙏

  • @smurglerer
    @smurglerer 3 роки тому +6

    Super helpful, easy explanation. A friend works with battery development and says he couldn't explain it better.

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      Thank you! Glad I got a professional's approval 😁

  • @malloott
    @malloott 3 роки тому +5

    You are a natural born teacher! Thanks for a simple and in depth explanation!

  • @jws3925
    @jws3925 3 роки тому +2

    I have learned so much from your battery build and I agree with your logic in the build. It made perfect sense to me. I am not a newbie to solar but I am to LIPO and will be venturing out to build my battery just as you did soon. I have been watching many videos of individuals building LIPO batteries and think I have gathered enough information and education to proceed. Your channel and build is, however, my favorite and will likely use a majority of your build. Thanks again.

  • @TheScoutFamily
    @TheScoutFamily 3 роки тому +1

    This is the most understandable video that I have seen on this topic. Thank you for making this and best of luck on you channel.

  • @norm4907
    @norm4907 3 роки тому

    Best discussion on this I have seen on the internet. Thanks.

  • @samsue1224
    @samsue1224 3 роки тому +1

    Thanks, very informative.
    I’m planning a build where I will install the cells into my 4x4 canopy frame. It is currently dead space. This will require the cells to be connected side by side to maintain a thin profile.
    The canopy is Aluminim so should help with heat dissipation

  • @svtosca3371
    @svtosca3371 3 роки тому +5

    That was amazing. Concise, clear and useful.

  • @jdbrinton
    @jdbrinton 9 місяців тому +1

    thanks! That was incredibly clear.

  • @IndependentOffGridRetreat
    @IndependentOffGridRetreat 2 роки тому +1

    Great video Thanks for that info. I actually am just top balancing my first lithium battery pack and when i seen how much they can expand at full charge. I appreciate this information. keep up the good work!!!

  • @yoking4925
    @yoking4925 3 роки тому +2

    good explanation about compressing a battery set and how a LiFePo4 battery works. thanks

  • @spf2000
    @spf2000 3 роки тому

    Thanks for this simple, calm and clear explanation.

  • @MarkPrince1317
    @MarkPrince1317 3 роки тому

    Very great point 9:00 flaxable bus bar I will use copper wire with lugs
    Thank you for very very good point brother

  • @sattarpc
    @sattarpc 9 місяців тому +1

    Wow very simple explanation. Thanks

  • @montaguemonro565
    @montaguemonro565 3 роки тому +6

    Nice one mate! My batteries have just shipped, hopefully should arrive within the month. Also just going to badger you again about the battery heating video!

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      Haha no problem. I just got my heating pads yesterday as a matter of fact. Once we get better weather here I will get working on the video 😁

  • @kevinh265
    @kevinh265 3 роки тому +1

    Excellent transfer of knowledge. Very easy to understand and absorb. I am building a 12V 560 AH system for my sail boat. Thanks for taking the time to share your knowledge and experience. Cheers Kevin

    • @freelyroaming
      @freelyroaming  3 роки тому

      Thank you. Good luck with your battery build!

  • @dnc23x
    @dnc23x Рік тому

    building 8S LFP pack right now and trying to decide what is more important, compression or ventilation :) thanks for the hints.

  • @thenuts133
    @thenuts133 3 роки тому +1

    Thank you. That was a great explanation and very helpful. I have spent countless hours try to find all that information.

    • @freelyroaming
      @freelyroaming  3 роки тому

      Glad you found it helpful. It's exactly why I decided to make this video. There is a lot of misinformation and confusion out there about prismatic cell compression.

  • @kooscombrinck3753
    @kooscombrinck3753 2 роки тому +1

    Well said and explained!!!

  • @SAMSUNGANTE
    @SAMSUNGANTE 3 роки тому +2

    im doing my final work on faculty on li-ion batteries and im also building my own battery as part of the final work...anyway im listening to your video but as soon as i looked at stonework i knew that u are i croatia haha .... greetings from zagreb ..they say that Hvar is the sunniest place in croatia

    • @freelyroaming
      @freelyroaming  3 роки тому

      Haha yes we are quite proud of that title. Yesterday we literally looked up in the sky and saw the sun over us and clouds everywhere else.

  • @lukefarmer5391
    @lukefarmer5391 3 роки тому +1

    Nicely explained. Nice visuals as well. Thank you.

  • @SB-nt9fp
    @SB-nt9fp 2 роки тому +1

    Very informative video. Also, just subscribed as a result.

  • @JosephStory
    @JosephStory 3 роки тому +4

    Very informative, trying to decide what to do with my battery bank due to arrive in two months. Thumbs up for the feline photo bomb at 07:54

  • @honumoorea873
    @honumoorea873 2 роки тому

    Even under 1c delamination will happen, compression is mandatory for long term use. Mine are compressed for a year, I got some 3mm plastic foam between each cells that let them bloat a little if needed, but not too far, and as they bloat a little, foam pressure increase.
    2 plank, 4 rods 4 plastic tubes to insulate those rods, easy project.

  • @daantaelectricos
    @daantaelectricos 8 місяців тому

    Bastante útil ¡¡¡... excelente video y explicación, Bendiciones...

  • @posteroonie
    @posteroonie 3 роки тому +1

    Great explanation! I got the 280ah cells because I wanted to run an inductive cooktop without pushing the limits of the recommended max continuous discharge. That was before I heard of the compression issue. 1800w is about 140a, 0.5C. If I had bought 100ah cells even running the cooktop on reduced power I'd be at 1C.

    • @freelyroaming
      @freelyroaming  3 роки тому

      Definitely a good call to go up in size. Even if you don't need all the capacity but just having the discharge headroom.

  • @bobham919
    @bobham919 3 роки тому

    very concise and to the point. answers lots of questions for me. i don't plan for high output or high rates of charge. i think it might be best in my solar application to make a fixture. thanks so much for cutting through the nonsense of the peeps that half read and half learn the deal here then go online and claim they are professionals

  • @mojo68mitch
    @mojo68mitch 3 роки тому +2

    Very informative and well explained thanks

  • @musashi1707
    @musashi1707 3 роки тому

    Well said about compression

  • @HarryBrielmann
    @HarryBrielmann 3 роки тому

    I have been asking that simple question for quite a while and I liked your answer better than most. In particular it seems to me that lithium ions do not migrate from the cathode to the anode- they must transfer to as cations to the cathode and as atoms to the anode. In other words the charged battery must have lithium atoms ready to lose electrons to begin the flow that produces the energy needed. You generally used the term lithium element which I guess is better than most but it is vague. Also nobody wants to talk about the balanced chemical reaction or the half reactions of a lithium iron phosphate battery. I welcome your thoughts.

  • @BobCollins42
    @BobCollins42 Рік тому

    Do you have a reference/reading list you used for this subject?
    Your presentation is great, and I would like to dig deeper into the subject.

  • @MrEroshan
    @MrEroshan 3 роки тому +1

    My understanding from research is that these aluminum case cells with be concave on the sides when discharged and convex when fully charged. So if you bind them together when discharged with a small pressure then they will be properly compressed when charged. My CALB cells have more rigid plastic cases, I have never seen them swell, but I still have them bound together with a ratchet strap.

    • @freelyroaming
      @freelyroaming  3 роки тому

      Yes the enclosure that contains the raw cells have a lot to do with the amount of compression. My aluminum cased cells already have compression built in so very little fastening will be needed if someone chooses to do it.

  • @Daraghfly
    @Daraghfly 3 роки тому +2

    Very helpful thank you very much, happy new year.

    • @freelyroaming
      @freelyroaming  3 роки тому

      Thank you and happy New Year to you as well!

  • @gavindavies8457
    @gavindavies8457 3 роки тому

    Nice video's 👍 just found your channel and it has inspired me to build my own lithium pack too.
    Used your link for AliExpress to get 4x 280ah with free UK shipping and went for a Daly 250A BMS with Bluetooth. 🤞 No import charges.
    Keep up the good work my friend.

    • @freelyroaming
      @freelyroaming  3 роки тому

      Thanks Gavin! Good luck on your build.

  • @RaikoH6644
    @RaikoH6644 3 роки тому

    Thank you very much.

  • @briannakelly26
    @briannakelly26 3 роки тому +1

    Perfect explanation. Thank you

  • @AveRage_Joe
    @AveRage_Joe 3 роки тому +1

    Excellent explanation! 👍

  • @timburke3096
    @timburke3096 3 роки тому

    I contacted CATL and their engineer said for their 280Ah cells that fixturing with the 300kgf preload was required for all applications. I think it depends somewhat on the specific cell construction.

  • @budmartin3344
    @budmartin3344 3 роки тому

    Just FYI if you are going to tightly pack the cells together, make sure to add another insulation sheet between cell.
    I just check my LISHEN cell the Voltage between the case of the cell and the Negative terminal, it shows the same Voltage reading as when measure between Positive terminal and the Negative terminal, 0V between Positive terminal and the case.
    So I do the same test with the 90Ah Liitokola and get the same result.
    So the case is positive on my batteries.
    I put 100 Ohms resistor on Negative and the case, the Vdrops on the resistor is 1V, = 10mA.
    That is not low leakage.

  • @The-Wise-One
    @The-Wise-One 2 роки тому +1

    Great Video. I have a question, im considering a Lifepo4 raw cell x 8, for a 12v camper setup, for 600ah. Im only at the beginning stage of learning, and its a large hurdle atm, and keep falling back to off the shelf batteries. Eager to go the build method, concerned if there are more failure rates with building a kit, vs off the shelf batteries. Do the stand alone BMS units fail more often, and do we create more problems with build kits vs off the shelf batteries?

    • @freelyroaming
      @freelyroaming  2 роки тому +1

      If you were to crack open off-the-shelf batteries you would find that there is no magic trick that makes their components work better than a diy one. It's really just knowing how to pick a good components and understanding how to assemble them properly and safely. I just uploaded another build video that shows a simple build but using good quality parts. That might be of some more help.

  • @vpeters2647
    @vpeters2647 3 роки тому

    Where are you, the stone work is awesome. I've been trying to get a good answer on this for a while, and
    have come to the same conclusion, depends on the application ! Thanks for the great videos.

    • @freelyroaming
      @freelyroaming  3 роки тому

      Thank you. I am on Hvar Island, Croatia at the moment.

  • @fredmartens7126
    @fredmartens7126 3 роки тому +1

    Great great info... again.. thanks!

  • @АлексейКовалев-я2в
    @АлексейКовалев-я2в 10 місяців тому

    Hello! Please tell me, I want to assemble EVE 105ah batteries, is it possible to place the batteries with the contacts facing the face (horizontally on the edge of the battery), and not up, as is the case in most cases? I read that lefepo4 can be placed in any position, just not with the contacts down, but I would like to hear your opinion! Will this interfere with the normal operation of the batteries?

  • @JRP3
    @JRP3 3 роки тому

    People have had swelling at low C rates with uncompressed cells. I would always recommend compression.

  • @tomasthomas7407
    @tomasthomas7407 3 роки тому

    DEFINITION of TERMS, you Gotta just Love IT 🤣
    Imagine, everyone on same page with understanding of terms, what could be done⚡️⚡️
    Thank You. For a timely article, andi love your location …🌍🌍

  • @jonknouf3006
    @jonknouf3006 3 роки тому

    Thanks for taking the time to research 🧐 and then communicating what you know and your thoughts on these batteries 🔋.I have 2 -200 amp lithium similar to yours with a 120 Daly . Tested the low temp and it worked perfectly.I am also thinking of limiting discharge to 20 % and charge to 90% .At this point I’m putting them in a Rv Class C w/2000 inverter.what are your thoughts on 20% - 90 % ?

  • @CG-xr5bz
    @CG-xr5bz 2 роки тому

    If i have 8 Lifepo4 eve 280ah batteries and am running a14k btu ac do i need to compress?

  • @petewoodhead52
    @petewoodhead52 3 роки тому +1

    Intercalation, Nice! A new word and and excellent explanation of what it means. I've enjoyed your battery build series. Thanks and good luck on your travels. Question: If I use one of your amazon links will you get some benefit from my purchases even if they are not for the linked product? Safe journey and I'll spread the word.

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      I would get a small affiliate commission for the sale. Thank you!

    • @petewoodhead52
      @petewoodhead52 3 роки тому

      Excellent, That's what I hoped.

  • @hankmishima4798
    @hankmishima4798 3 роки тому

    Thanks! Useful information.

  • @johnlazdins2004
    @johnlazdins2004 2 роки тому

    I wish to build a battery bank for off grid 48v to process power from p.v. panels. However the area in which I live is generally warm to very hot in summer, South Australia. Is it possible to use 1-6mm aluminium sheet cut and fitted between each cell with some of the ally projected past the cells front and rear by around 100mm or so. That should act as a heat sink, or is there some residual voltage, or worse current between calls, that is if the cells are made of metal, like ally as u tubers say.. Battery drain will not be large as it's supplying 5k 48v inverter, but to a small house, minimum apps. Thanks

  • @dtvking
    @dtvking 3 роки тому

    Very well explained and presented. Thanks

    • @freelyroaming
      @freelyroaming  3 роки тому

      Thank you Mark for watching and your comment.

  • @flyingtools
    @flyingtools 3 роки тому

    Thank you for a great video, you explain it just perfect 👍🏻

  • @stefankrimbacher7917
    @stefankrimbacher7917 3 роки тому

    The secret is an equal pressure, not only the force of about 3000N shown in the datasheet. Therefore I would prefer a thin layer of epoxy between the cells to reach this state when you apply the mentioned force.

  • @WimSchutten
    @WimSchutten 3 роки тому +1

    thank you.

  • @JAVIERLLAMAS10
    @JAVIERLLAMAS10 3 роки тому

    Nice video. By the way, i think it would have been a lot better for you if you just have bought a smart BMS, and that would have saved you buying a shunt, and the temperature sensor. Can you make a test with the inverter and make some test of discharging? Many people wants to see exactly how Daly BMS behave and if they can really reach 120a for 10-15 minutes or so. There are not many videos of the tipical Daly in action, most people just complain about them. You mentioned you would like to test some induction cooking, that would be really really interesting. I think your case is really useful for many people because out there there are lots of 24v setup videos, but not many tests on 12v in real life conditions.

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      A smart bms would not replace a shunt because it does not measure capacity by measuring amps as you would using a coulometer. It just shows voltage which is not what you want to use to calculate SOC. The Victron battery sense temperature sensor works with my MPPT chargers which a smart bms would not. This setup give me much more flexibility and much better accuracy in determining depth of discharge. There are a lot of people who do not understand how these systems work and expect more than they should which leads to complaints online. There are far more people who are happy with these. I have not seen enough data on these smart BMS units to trust that they will do what they say. I also prefer to not have any parts in my systems that try to do multiple functions at a time. It means one device failure instantly turns into multiple device failures and become more difficult to replace for me as a full-time international travelers. For critical systems, dedicated single purpose devices are simpler, less prone to failure and easier to replace if needed. I will need to upgrade my inverter from a 1kw to a 1.5kw inverter to draw 120A. That's is why I chose this unit. I don't expect to ever reach 120A with my current setup. If I upgrade my inverter, I will most likely also upgrade the BMS to provide more capacity so I never need to run it at peak capacity.

  • @ricardophelps6323
    @ricardophelps6323 4 місяці тому

    Nice logical explanation. I have 16S 3.2V cells x3 in parallel. The max my system will charge is 200A (with no loads) and the most the inverter will draw is 200A. Divide that by 48 cells is max 4A charging/ discharging per cell. C1 rate is 280A so 4A is equivalent to C0.014 charge/ discharge rate. Compression is NOT required for this config I would much rather allow the cells to breathe and exhaust any heat. The BMS temp probe is stuck to the upper side of a central battery and is ALWAYS at room temp, never seen it rise even 1 deg C higher even when charging full 200A. 4A is like a trickle charge for these cells.

    • @streefland
      @streefland 4 місяці тому

      You should divide the current by 3, not 48, because the current is distributed over 3 strings of 16 cells. That will result in a maximum charge/discharge rate of 0.24C.

    • @ricardophelps6323
      @ricardophelps6323 4 місяці тому

      @@streefland So your telling me if the total current flowing is 200A from 3x batteries in parallel then each cell has 67A flowing out? That makes no sense. The C rating is per cell, not per battery.

    • @streefland
      @streefland 4 місяці тому

      @@ricardophelps6323 Exactly, there is 67A flowing through each cell, so the C rating for each cell is 0.24.

    • @freelyroaming
      @freelyroaming  4 місяці тому

      The calculation is easy. Forget individual cells. Look at it as a complete pack. If you are charging a 16s3p pack with 200A, then you are using a charger that is outputting 58.4v which equates to charging output of 11,680w. Total pack capacity is 43,008Wh. Total Ah for the pack is 840Ah. 1C for this system is 840A. So 200A charge is a 0.24C. (200÷840). Technically you are charging at 0.27c (11,680÷43,008) because the charging voltage is higher than the nominal voltage (58.4v vs 51.2v) but going by theoretical c-rate in amperes 0.24c is more widely accepted.

    • @ricardophelps6323
      @ricardophelps6323 4 місяці тому

      @@freelyroaming I was just using simple math if my charge controllers put out 200A total and there are 48 batteries all taking current equally then each cell takes 4.2A or 67A per 16S pack. Do you agree with that?

  • @babylonfive
    @babylonfive 3 роки тому

    Really nice.

  • @wincrasher2007
    @wincrasher2007 3 роки тому +1

    this is why I selected batteries with cylindrical cells. alot more durable and resistant to this.

    • @freelyroaming
      @freelyroaming  3 роки тому

      Yes cylindrical cells are essentially self-compressing in their method of construction and do not suffer this effect. But they do take a bit more know how and time to assemble into similar size packs. They both have their pros and cons.

  • @unionse7en
    @unionse7en 2 місяці тому

    The sides of the cells transfer about 10 times the amount of heat as the other surfaces, because of the way the internals are folded. Anyway this video is about 3 years old and EVE has finally made public the datasheets with the compression fixturing info.

  • @timburke3096
    @timburke3096 3 роки тому

    People are still saying you need to compress the cells because the spec sheet has the capacity test listing as done with compressed cells.

  • @SolarEngineering
    @SolarEngineering 3 роки тому +1

    good content, thanks.

  • @tex959
    @tex959 3 роки тому

    I'll rarely exceed .2C discharge and .15C charging. 95% of the time I'll be keeping these cells between 20% and 80% state of charge. Does compression seem necessary in my case?

  • @gluteusfanious9351
    @gluteusfanious9351 3 роки тому

    Negative flow to positive? Heresy! ;-) Just found you channel, love it!

    • @freelyroaming
      @freelyroaming  3 роки тому

      Thats right! electrons always flow from anode to cathode! Thanks for watching.

    • @gluteusfanious9351
      @gluteusfanious9351 3 роки тому

      @@freelyroaming No they don't, that's crazy! next thing you'll tell me is centrifical force is fake. And the world is flat supported by turtles! If you cant tell, I'm pulling your chain and LOVE that you are spewing FACTS and not rumors!

  • @sfmag1
    @sfmag1 3 роки тому

    Isn't this just about the case you put the cells in? How flexible or non flexible it is?

  • @keithdoubleday9279
    @keithdoubleday9279 3 роки тому

    Sorry if I missed this in your series, but how did you charge the cells in your battery build? Seems like you assembled the battery and then charged it up using your generic battery charger through your BMS and Active Balancer. Just getting ready to start this process and the top/bottom balancing process still has me a bit challenged! Thanks and great videos. Looking forward to being able to travel to Croatia to see family and friends again!

    • @freelyroaming
      @freelyroaming  3 роки тому

      The easiest and in my opinion the best way to charge new cells is to connect them all in parallel and top balance them by charging the together using a constant voltage/current charger to 3.65v. Or like me, if you can't get your hands on a charger like that, you could rely on your cell balancer and BMS to gradually balance out your built pack over a few days with as many charge/balance cycles as it needs to get it up to the proper pack voltage of 14.6v. What I did is far less reliable and requires a little luck that your cells are close in SOC but can be done in a pinch. Having a way to log peak voltage like I can with my Victron Smartshunt prevents you from having to constantly check with a voltmeter.
      The BMS will keep each cell from over charging and the balancer will level them out between charge cycles which allows the charger to eventually fully charge each cell. The same way it would work if your cells ever got out of balance in the future.

  • @gregboyd4321
    @gregboyd4321 3 роки тому

    So I hope ur having a fabulous day to be comming up! I have a question about lithium battery configuration to a 4s 12v parallel system. I was given 4 100ah prizmatic GBS lipo4 batteries without a BMS. I wast to come out with a 400Ah 12v parallel system. What would you do to configurat these 4 batteries to meet my needs. I simply did a negative to negative on one side and the same for positive on the other side. This I was told to be incorrect for lipo4 batteries. What would ur thoughts be here? O off subject a check should be in ur account soon complaints of the new administration. Will be awaiting ur response. Thanks again ciao

  • @scottweikert5189
    @scottweikert5189 3 роки тому

    Your reasoning matches that of a couple of other folks whose recent videos I've watched.
    Any idea, *very* roughly, what rate your average van-installed system is going to be discharging and charging at, C-wise? Assuming average battery capacity, usage, solar charge capacity, DC-DC and shore power charge capacities?

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      I am at a very low c rate. Most of the time less than 0.1C and probably never above 0.2C. same for charging. The most I can push while charging is 20A from the DC-to-DC charger and full solar which maxes out at 30A. That's a 0.18C charge rate.

  • @tomsans1946able
    @tomsans1946able 3 роки тому

    Great build! I'm planning on building my own. I have a question you might be able to answer for me. I'm in a cold climate and I'm worried about charging at too low of a temp. I'm wondering if you know if I open the circuit on the black lead from the BMS if it will stop the charging? I have several ways I can disconnect the circuit so it will cycle back on when it warms up again. Do you think this method will work? Do you know if the BMS will cycle back on properly? Can't wait for more of your videos. I might doubble up and make a 560AH 12V using one BMS. I'm planning on using the Daly with the BT if I can find it at a good price.

    • @freelyroaming
      @freelyroaming  3 роки тому

      One of my next videos will be using a thermostatically controlled switch to turn DC heating pads on and off to keep batteries warm in cold temps. If you are planning to keep your cells in those conditions, I would recommend doing something like that as well. If you open the negative circuit the battery will stop charging. That's indeed how the bms' charging protection works. As long as you reconnect the bms and provide proper charging current and voltage, it should start charging again.

    • @tomsans1946able
      @tomsans1946able 3 роки тому

      @@freelyroaming Thank You I thought it would work but asking for advise helps. I will consider a heater in the circuit too. I'll be watching for the video.

  • @SnowyOwlPrepper
    @SnowyOwlPrepper 3 роки тому

    Does the fixture refer to a cell or a battery in the data sheet? The extrapolated portion of the curve suggests more cycles and the measured part of the curve the opposite. Perhaps the experiments were on a cell. The total cycles being representative of a perfect balanced life cycle model. How else could the extrapolation be meaningful if in a package of cells? I would imagine the atmospheric pressure is a factor. In a pressure vessel equivalent to 20-30 head feet of water, the cell would be ideally compressed. Does anyone connect the terminals with spring force like a flashlight light batter terminal? Striving for that stress free lifepo4.

  • @michaelagnew7825
    @michaelagnew7825 3 роки тому

    Interesting........ life used to be so simple !

  • @alonzodesantis6989
    @alonzodesantis6989 3 роки тому

    Very informative on the fence about lithium I'm a fla man question why use buss bars to connect batteries I use 1/0 cable then to a buss bar for loads and charging. Have a Happy and Healthy new year

    • @JM-yx1lm
      @JM-yx1lm 3 роки тому +1

      Those are still pretty stiff. I think the best thing is those copper braided bus bars

    • @hightower5564
      @hightower5564 3 роки тому

      the best thing to use for bus bars in actually aluminum flat bars. Thwy produce aluminum oxide which coats the aluminum and prevents further corrosion of the aluminum When using copper they must be coated with something or else they will corrode when the electricity is applied. Thats why most copper wires are either tinned or made with aluminum (CCA)

    • @freelyroaming
      @freelyroaming  3 роки тому

      Copper-clad aluminum is actually used to save money versus solid copper wires. Aluminum has is benefits when it comes to corrosion resistance but it has 50% less conductance than copper (0.4 megaohm/cm vs 0.6 megaohm/cm) That just means you will need to use thicker wires if it's aluminum cored.

  • @brucekempf4648
    @brucekempf4648 Рік тому

    I just purchased a 12.8V LiFePO4 20AH battery from Amazon and made a huge mistake by trying to see if I could power my 1000 watt Microwave oven using my 1000 watt Inverter. It powered to microwave oven but I noticed the voltage dropped to 10V during this test. I stopped it after about 20 seconds. Battery voltage went back to normal and it seems okay. I am worried that I may have caused damage that will greatly shorten its life. Do you think I caused permanent damage?

    • @freelyroaming
      @freelyroaming  Рік тому

      It definitely could have caused some degradation. Pulling 1kw from a 20Ah pack is nearly 4C. LiFePO4 packs should not really exceed 1C discharge rate. But for a short moment, it might be able to withstand it. I would not try pulling that much wattage from any pack less than 80Ah.

  • @jackrussell4653
    @jackrussell4653 3 роки тому

    Freely Roaming, For your DALY BMS how did you decide how many amps to pick? I see you chose the 120 amp bms.

    • @freelyroaming
      @freelyroaming  3 роки тому

      It is based on your expected maximum power draw. My inverter is 1kw so I know including all my other appliances, I will never draw over 1500 watts at one time which is approximately what the 120A will allow.

    • @jackrussell4653
      @jackrussell4653 3 роки тому

      @@freelyroaming The maximum watt appliance I will be using is a 1200 watt blender. I was thinking of getting a 2kw inverter to cover it. Does that sound like overkill for the inverter? If I end up going with the 2kw inverter, then I would need a 250A BMS??

    • @freelyroaming
      @freelyroaming  3 роки тому

      250A would be overkill. I would go with a 150A or 200A at the most for this application.

    • @jackrussell4653
      @jackrussell4653 3 роки тому

      Do you think a 2000 watt inverter would be overkill if the maximum watt appliance I would be using is a 1200 blender? Thanks for your inputs.

    • @freelyroaming
      @freelyroaming  3 роки тому

      No I think a 2kw inverter will give you good headroom for that.

  • @dnc23x
    @dnc23x Рік тому

    gooooood video!!

  • @neojted
    @neojted 3 роки тому

    What do you mean by compression?

    • @freelyroaming
      @freelyroaming  3 роки тому

      It means you should use a container that push the cells together with a certain amount of force to keep it from expanding. Most common method is using plywood, threaded rods and nuts.

  • @blackduck7851
    @blackduck7851 3 роки тому

    Great videos. Sadly I saw them too late and just bought 4 x 240Ah 12VAGMs for my boat! I think for the same price I could have followed your lead and bought 16 of the 3.2 volt packs. Forgive me for prying but it looks suspiciously like Croatia there? (I am an Aussie on a Catamaran in Croatia )

    • @freelyroaming
      @freelyroaming  3 роки тому

      Yes it is indeed. We are currently isolating in a small village on Hvar Island riding out the storm.

    • @blackduck7851
      @blackduck7851 3 роки тому

      @@freelyroamingAhh yes I thought I recognised the stone work! I am just north of Sibenik in a bay at Pirovac. Love Hvar, a lovely island, have been there a few times. I also have a self made (very amateur ) Van that (pre covid) I would take around Europe when not on the boat. I like Croatia but I will say, after a few years here these storms are driving me insane! Keep safe and sane!

    • @freelyroaming
      @freelyroaming  3 роки тому

      Haha yeah there are some stiff breezes around here. We've bareboat chartered weekly trips out of Split 3 times in the last year. The islands are great cruising grounds. We are looking at getting our own boat to live aboard and travel with in the next year or two as well. Enjoy your time and hope you are staying dry and warm.

  • @xsauce3858
    @xsauce3858 2 роки тому

    The datasheet shows the aluminum enclosure is a fixture and it apply compression about 300kg of force. I don't think it's that necessary to apply additional compression to raw cells since the aluminium case is a fixture

  • @fredio54
    @fredio54 3 роки тому

    What and where is that building at 0:11 please?

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      That's the Buzludzha monument in Bulgaria.

    • @fredio54
      @fredio54 3 роки тому +1

      @@freelyroaming Thank you very much! How fascinating! To me it looked like the starship enterprise in very bad condition :-D Thanks for the chat on compression, too.

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      Yes it's like an abandoned spaceship. There are some fascinating before and after comparison photos online of what it used to look like.

    • @fredio54
      @fredio54 3 роки тому

      @@freelyroaming Thanks for pointing that out. What a truly amazing place and what a true shame that it was not preserved and maintained and kept in use for something, such as a library or similar. It's spectacular and just wonderful to look at even on a screen. Cheers!

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      Yeah Bulgaria is a relatively less wealthy part of Europe where money to restore and upkeep such a place can benefit people elsewhere. There are now efforts to keep it in a reasonable condition with some funding from the various preservation societies. When we were there they had constant security on site to keep it from further vandalism.

  • @ScinnerNo1
    @ScinnerNo1 3 роки тому

    The best thing I can think of is to enclose every cell in a thick, let's say 1/2 ", aluminum case that fits the cell perfectly and wont let the cell expand. That way compression only occurs when the cells are trying to expand and also dissipates heat at the same time?

    • @freelyroaming
      @freelyroaming  3 роки тому

      It would work for sure but really not necessary for the relatively small benefit you might see from it.

    • @ScinnerNo1
      @ScinnerNo1 3 роки тому

      @@freelyroaming Not even if you almost always charge/discharge at 1C?

    • @freelyroaming
      @freelyroaming  3 роки тому

      For me that answer is yes because it most likely would need to be a custom made enclosure and the cost and time that would go into building such a case just wouldn't pay itself back as compared to similar improvements you would get from threaded rods and plywood that would be cheaper and easier to use.

    • @ScinnerNo1
      @ScinnerNo1 3 роки тому

      @@freelyroaming Sorry, I meant the idea it self. Lets say I'm a welder with an unlimited source of aluminum? Would it be better for the longevity of the batteries if you are planning to abuse them with 1C charge/discharge?
      ​I also have another question. The Daly BMS seem to be limited to half the amperage when charging. Do you know if it will shut off charging or limit the current?
      Also I love the way you explain things and thank you so much for putting this out there! I will recommend this channel to all my lithium pals!!

    • @freelyroaming
      @freelyroaming  3 роки тому

      Thank you. Well conceptually it would work. You would just want to electrically isolate each enclosure from the next cell as they are often connected to the anode. As far as the bms, it should protect from both charging and discharging. A common port unit should not have different amp ratings between in ane out but a separate port will usually have a limited charging amp capacity and can offer better protection.

  • @dnc23x
    @dnc23x Рік тому

    THE CAT is watching me :)

  • @steve82608
    @steve82608 3 роки тому

    Do you still feel the same about compression? It seems like you later actually added some compression to you battery box in a later video. Like you, I am not convinced that most of us (non-1C charge/discharge) really need to worry about it. However, if you've changed your mind, I would like to know!

    • @freelyroaming
      @freelyroaming  3 роки тому

      Still feel the same about compression. Meaning that is not necessary for low amp draw applications. I'm expecting to use mine for induction cooking in the future so I've added a fixture for now.

  • @azores-pv6ft
    @azores-pv6ft 3 роки тому

    Ok I’m impressed with your knowledge. Now tell me if they are safe.

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      This is probably not a video for you like I said at the beginning of the video. It's not about safety either. It's about longevity. There will be a video about safety coming soon.

    • @richardowens9061
      @richardowens9061 3 роки тому +1

      Lithium Iron Phosphate (LiFePO4) is the safest formulation of lithium batteries available. But, they're still batteries that are capable of storing enormous amounts of energy. And, having that much energy on tap has inherent danger associated with it. The same can be said of a standard wall outlet. The outlet technology is safe. The electricity that flows through it, though, has the potential of being very dangerous. That's why you should not do your own electrical work, unless you are familiar with the dangers of electricity.
      For example, if you drop a wrench across the terminals of a 100 amp hour LiFePO4 battery, the wrench will instantly weld itself to the terminal and then melt within seconds right before your eyes. Then, you have molten steel melting its way into the battery and it's so hot that it could start a fire. But, if you don't drop a wrench across the terminals, none of that will happen.

  • @OffGridGarageAustralia
    @OffGridGarageAustralia 3 роки тому +8

    This compression virus is widespread...

  • @mickwolf1077
    @mickwolf1077 Рік тому

    find a middle ground, don't compress them but restrict them from swelling, then you wont have to worry about the bus bars being under stress.

  • @shinosg-wiz4619
    @shinosg-wiz4619 3 роки тому

    Very interesting thank you for the video. There's a guy that has a small car like mine running li-ion, just a 4kw battery pack NOT COMPRESSED...and it's still running after 13yrs. Like Tesla modules 18650 aren't compressed though in a high draw setting ..being an ev.

    • @freelyroaming
      @freelyroaming  3 роки тому +2

      The compression discussion is specific to prismatic cells and not cylindrical cells. Tesla and most automotive batteries use cylindrical cells. They are built using a layer of anode on top of a layer of cathode with a polymer sheath in-between and rolled up tightly so it is essentially a self-compressing form factor by design. Cylindrical cells do not fall into the discussion of cell compression for that reason. If you were building a diy electric car using prismatic cells, you would be recommended to place them in a fixture. As you can see in my video, even without compression, you can still get 2500 cycles before the cells degrade to 80% capacity at max C-rate. Even at 80%, it's still a serviceable pack for many more cycles to come. So 13 years is not that surprising of a time frame for a pack to be 'still running'. It's the number of cycles and the type of cycles the pack has experienced that matters.

  • @KH-yv1bo
    @KH-yv1bo 3 роки тому

    are ur batteries compressed

    • @freelyroaming
      @freelyroaming  3 роки тому

      Right now they are not. My max draw is under 0.2C which is very low for my pack.

  • @kylegohawks8604
    @kylegohawks8604 3 роки тому

    Definitely don't over charge a battery 2 fast. 19 years ago when I installed car stereos. I seen the guy who was my boss. Who was trying to tune the big system. Battery died. So he hooked up the 200 amp jump. Tuned it then forgot to take it off and left it. As I was working on my car. It exploded

  • @nbarachkov
    @nbarachkov 2 роки тому

    Are you leaving in east Europe? I saw some marks that point me to this conclusion, maybe we are neighbors 😁

    • @freelyroaming
      @freelyroaming  2 роки тому

      Croatia in the Dalmatia coast

    • @nbarachkov
      @nbarachkov 2 роки тому

      @@freelyroaming ah, I saw Buzludja monument on the begging of the video and also similar building structure of houses around you, so I thought you are in Bulgaria 😁

    • @freelyroaming
      @freelyroaming  2 роки тому

      @@nbarachkov we are not too far 😀 We explored Bulgaria in 2019 and that's when that video is from.

    • @nbarachkov
      @nbarachkov 2 роки тому

      @@freelyroaming Nice 😁

  • @jfjjjjfj
    @jfjjjjfj 3 роки тому

    Hi cat 😸😸

    • @freelyroaming
      @freelyroaming  3 роки тому +1

      She is the mama of a couple kittens we are currently caring for. Very intrigued with what I was doing talking to myself ☺️

    • @jfjjjjfj
      @jfjjjjfj 3 роки тому +1

      @@freelyroaming They are so cute. I have two right now.
      Worlds cutest killermachines 😸😸
      And I like your videos too, of course 😺

  • @richardowens9061
    @richardowens9061 3 роки тому

    My feeling is that if your application is such that you're going to be pushing your batteries to 1C charge or discharge rate regularly, you need to increase the size of your battery bank. The cells were not designed to be compressed. But, they were designed to permit air flow between them to improve the efficiency of cooling - which compressing them would defeat. So, I recommend you not second guess the engineers who designed the batteries and, instead, work within the safe limits of the design in such a way as to maximize the life of your batteries.
    For example, your car may be designed to have a maximum speed of 120 miles per hour, but that doesn't mean you should drive it that fast all the time. And, if you do, you can expect the car to have mechanical failures more often - because, the engineers who designed the car did so with typical uses in mind, and driving the car at its maximum speed all the time is not a typical application for a car. And, if you need a car that can easily handle being driven at 120 miles per hour all the time, you need a car that is designed to totally different specifications and with much greater performance characteristics - like having a top speed of 200 miles per hour, and not 120 miles per hour. In other words, you need a race car.

    • @freelyroaming
      @freelyroaming  3 роки тому +2

      The datasheet from the manufacturer actually talk about using a fixture being able to handle 300kgf amount of compression force to achieve the rated cycle life with 1C sustained draw rate. It is discussed and shown in this video but I suppose you perhaps missed it. So it is the engineers who designed the batteries who recommend compression for high discharge rates. Not anyone else. These are not based on my feelings and there is no second guessing happening here. This is per their engineers' and designers' recommendations. You can easily find the datasheet yourself and see what it says. Just Google 'EVE LF280 datasheet'. The datasheet should say 'Version E' for the most recent revision. 1C is also their recommended maximum sustained discharge rate. It is not a burst discharge rate. The datasheet also states that plainly. In fact if you see the part of this video (7:25) that shows the manufacturer's tests where they cycle the cells 3500 times at a constant 1C rate, you will see that it is in fact what they were designing these cells to do. A grade A cell needs to meet the specs from their test or it does not pass as grade A. These are not personal opinions. They are exactly what the engineers designed for them to do. Using your analogy, these cars can do 200mph but they are designed to run at 120mph all the time or they do not meet spec.
      But of course that is different than saying it would be better if you ran at 0.5C for even better longevity. I believe that to be the case as well but for anyone who needs to run them at 1C, they are designed to do so with the proper fixture attached.