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THIS may stop the battey debate

Discussion in 'Pro/Adv Discussion' started by ImJim, Jul 21, 2015.

  1. ImJim

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    We all wanna know if lipo break in is really useful and not a waste of time.
    I did my own experiment because I found myself feeling the same way as you. Take this for what you want, it's my own results. I purchased 3 of these specifically for one of my TCopters. I'm sorry I don't have a write up or anything, but here's what I have.

    I use a charger that measures internal resistance (Powerlab 8 v2 + 72A 24v PSU). In my opinion, outside of voltage sag and other obvious factors, internal resistance is the only way to monitor the true health of your battery. I labeled each battery (1,2,3) and dated them. Note: 'normal' flight for me can be any combination of docile or hard acrobatic flight (landing at 3.8V/cell and ice cold down to 3.2V/cell and quite hot. The initial IR of each batt was around 5-10 milliohms before first charge cycle and dropped to about 1-2 per cell after the first few charge cycles post flights. I did notice that battery 1 took longer for the IR to settle down closer to zero. Could just be a coincidence.

    • Battery 1: No break in, charged @ 1C and flew normal. After first charge subsequent charges ranged from 2C to 4.5C. (4.5C being 10amps)

    • Battery 2: One full cycle @ 1C and flew normal. 2C-4.5C charge rates .

    • Battery 3: 3 full cycles @ 1C and flew normal. 2C-4.5C charge rates.
    I didn't treat any of them different. Flew hard some times, flew gentle other times. I always put them in storage charge (3.83/cell). Typically charge before flight in parallel from 15-30amps depending on time restrictions.Today all three Lipos are ~1 year old and in the neighborhood of 200-250 cycles each pack. For the most part, all three are just as strong as day 1. Battery 1 has a slight puff and I can 'feel' it start to sag toward the end of flights, while the other two I don't. Does this have anything to do with the break in? Impossible to say.

    As far as internal resistance goes, all three are still under 10milliohms. Battery 1 cells are in the range of 8-10 per cell, while Battery 2 and 3 are sitting around 5 per cell.

    My opinion: On these smaller packs, does it really matter? I don't think it makes much of a difference. I think your best bet when you get a new pack is to do one cycle at 1C or less just to monitor the voltage in each cell before your first flight. It's a great safety measure and a good part of a pre-flight maiden check if it's a new pack. On my big 6S 5000mah packs, however, I think it does matter. The cells are larger and I always do slow long cycles and monitor internal resistance closely before first flights. The main reason being I want to establish a steady internal resistance before I'm yanking 2000 Watts in a WOT vertical drop with my big bi-plane. Hope this was somewhat informative.
     
  2. msinger

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    The idea of breaking in the smart batteries seemed to magically appear shortly after the Phantom 3 came out. I never saw anyone mention this with P2 smart batteries.
     
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  3. ImJim

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    True, that's the craziest thing about this.
     
  4. msinger

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    In any case, thanks for sharing your results! The people who were suggesting the break-in period did not have enough information to prove it worked. So, I'm not sure what the hype was all about.
     
  5. ImJim

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    The facts are here: no noticeable difference for all that work. So instead of wasting their time with never-ending break in processes with each battey, people should fly simply without any afterthoughts and enjoy this marvelous piece of technology.
     
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  6. BuckRogers

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    I purchased a few extra (4) batteries for my phantom. I flew them in close proximity to 50% the first round just to make sure there's no factory problem. I take a peak at voltage per cell to make sure they are equivalent, then next time, I fly them all to 30% and land. Part of my preflight check is to pop over to the battery menu and look at voltage per cell to make sure they all are equivalent.
     
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  7. N017RW

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    I think it [break-in] arose form the notion that DJI created this expectation that the P2 packs would last 300 cycles based on the discharge counter and many were getting less than 20% of that before puffing and other issues causing crashes, etc. It was assumed by some to be the fault of not breaking-in and thus to prevent similar experiences with P3 batts. the idea was posted.

    The fact that you have all this 'stuff' (intelligence hardware/software) between you and the battery cells is supposed to eliminate all the mistakes and special knowledge or experience to use them.
     
  8. Dome

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    Working on Lipo battery for other porpouse than RC models, I and my collegue never considered break-in and nobody of us care abut it (apart from RC fanboys!). We care, instead, about burn-in period that is very important when using cells for instant surge of high power (like motors, actuators and so on...). The burn-in suggests to use battery until reach 3.80V level and stop, for at least 10-20 times: if all goes normal in this time, battery is ok to use full charge.
    Internal resistance is a secondary effect of a quantistic behaviour of the anode through cathode (and viceversa) current flow. Being it "quantistic", the human reading of this effect is simply "statistic". Some cell has longer life (flat curve mOhm) and other shorter (ripid raise curve mOhm). It's sad but no way to avoid. Add to this a cell production system that try to go to perfection, but it's not (for the moment) ! Drain impurities from litium and to get it 100% inert in the real word does not exist.
    One note: more cells = more trouble. It's enough one cells working fancy and your battery is junk. $149 of litter. I support the idea of a modular cell battery ... but DJI has it's own business on that.
     
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  9. Dome

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    Just to complete, what I call burn-in, factory calls "formation". This is a critical process for new lipo sheets initialization. After this process, Q&A decide good/bad cells treshold.
    This process creates solid electrolyte interface on the anode and charging process begins with a low voltage which builds up gradually, instead of normal Constant-A/Constant-V charging curve.

    It is promising new Li-ion battery coming on the mass market, the Lithium Iron Phosphate (LiFePO4, LFE). It works at nominal 3.2V insteat 3.7V but is going (I hope) to be cheaper, stronger, safer and longer life, but, for the moment not suited for RC models. We'll see.
     
  10. silverstoned83

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    I didn't know you can charge P3 LiPo's on a PL8...

    Seriously, how is that supposed to be of any use to us P3 guys? It's more misleading in my opinion. Posting about your experiences with a random RC LiPo, likely of higher capacity and/or discharge rate based on your IR measurements, and comparing it to what we're seeing with the P3 is a pointless comparison. I could compare my Thunder Power 6S 5000mAh 70C to our P3 LiPo, but that would be like comparing a Ferrari to a Ford. Name brand LiPo's use matched cells that reduce the need for a break in process. Based on the temp of the P3 battery after a flight and cell imbalance, I think this LiPo is far from that of my Thunder Power LiPo's.

    I only used my experience with my PL6 to prove that I've witnessed how the cell IR reduces during the first 10-20 cycles. That's all there is to it. Higher IR leads to more heat, which leads to premature LiPo degradation. It's as simple as that.
     
    #10 silverstoned83, Jul 21, 2015
    Last edited: Jul 22, 2015
  11. BuckRogers

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    I dont think the PL8 will. But also would like to know how he did it
     
  12. silverstoned83

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    So everyone in the RC community should keep an eye on Phantom pilots to see how to properly do things? Perhaps there are more experienced RC pilots that might know a thing or two...

    The process of breaking in a LiPo has been around for over a decade..
     
    #12 silverstoned83, Jul 22, 2015
    Last edited: Jul 22, 2015
  13. brushlesheaven

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    He is doing his tests on regular Lipo battery, not the one P3 is using.
    Our batteries are being charged, discharged and balanced by the built in smart system.
    All we can do is provide DC power in to the battery and the rest is done inside of the battery...


     
  14. Dome

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    So, apart from break-in debate (I take seriously the @silverstoned83 experience about that!), what is the correct behaviour with P3 Battery ?
    This take as MY rule of thumb:

    1. New battery start-up. Fully charge it and use no more than 50% for 10 times, a failure will happen in this range. Start motors and hoover for at least 1 minute before flight. Look single cell voltage!! They need to be in the 0.02V range each other. Don't use new batteries for distance/altitude records !
    2. Charge: P3 batt don't let you do what you want! Too cold or too hot stops the charger. So obey to this, cooling or warming it.
    3. Discharge: Apart from the batt start-up process, use the trusted battery until you need it and then recharge it. There's no need to use full charge if you don't need it. Stop at 8-10% (no less than 3.1-3.2V x cell). At <3.0V cell start degrading but P3 battery doesn't allow to do that.
    4. Temperature: If DJI App show a temp above 60°C in the aircaft, get back and land the bird as soon as you can, although Voltage seems regular and discharge rate normal.
    5. Temperature again: Warm batteries before use if stored at <-20°C, cool batteries if stored at >40°C. For example airplane belly goes often <-20°C on some old aircrafts. For example a car trunk in a summer sunnyday can reach >40°C temp very easy.
    6. Storage: for more than a week storage, discharge battery to 50-60%, or simply stop charging at this point. P3 can autodischarge battery (10 days default) and the setting is in the DJI Pilot app.
    7. The P3 battery is "intelligent". So you can't manage it as normal RC models battery. The DJI "charger" is simply a power supply. The charger is inside the P3 Battery itself.
    8. Check regularly the battery connector on the P3 and clean contacts regularly with contract cleaning liquids.To clean into the contact hole of the battery simply slide in/out 3-4 times after cleaning the p3 contact!! This saves many battery errors during flight.

    That's all folks...
     
  15. N017RW

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    The 'formation' is done by/at the factory.
    During this, tests are performed on/for the very things being mentioned here.
    If the measurements meet spec. they ship.

    Until you do all these post purchase procedures in a controlled way, with many samples, over months of time, no statement one way or the other can be substantiated.

    If it makes you feel good why should you care what others think.?

    People don't engage in these discussions to have their minds changed so don't fret it too much.
     
  16. silverstoned83

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    Who really knows what the factory does during the manufacturing process... Unless you're involved in the assembly of P3 LiPo's, you assume too much. There are many corners to be cut in an effort to reduce manufacturing costs, which seperates the top quality LiPo's from the cheaper variety. I highly doubt DJI spends the money for the best lithium cells when it comes to Phantom batteries. The temperature and cell imbalance at the end of a flight confirms this IMO.

    As for testing the break in theory in a controlled manner over a long period of time.... I thought I mentioned that I've done that already. I have accumulated enough LiPo's to fill two .50 caliber ammo boxes over the last 8 years, I would not be debating this topic if this was not the case. I doubted the break in theory as much as anyone else, until I proved it to myself. I used LiPo's from multiple manufacturers, from cheap to expensive, and I watched/compared their health using IR measurements over their lifespan. I tested various charge rates to see how it impacts the cell IR along with various discharge rates/SoC to see how the cells react during the first few cycles in terms of cell imbalance, IR, and temperature. I have even abused some of them and have witnessed/verified the long term effects when compared to the same LiPo which was not abused.

    I've spent enough time monitoring them that I have reached a point of realizing what they like and don't like. Everything I have seen confirms that they HATE being discharged fully during the first few cycles, which will have long term effects. Discharging to 50% has proven to keep them happy and healthy during the first few cycles, which maximizes their efficiency and capacity over their lifespan.

    In the end, I could care less if everyone doesn't believe what I believe, 'my beliefs do not require them to.'
     
    #16 silverstoned83, Jul 22, 2015
    Last edited: Jul 22, 2015
  17. N017RW

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    [QUOTE="silverstoned83, post: 457250, member: 27997"]Who really knows what the factory does during the manufacturing process... Unless you're involved in the assembly of P3 LiPo's, you assume too much. There are many corners to be cut in an effort to reduce manufacturing costs, which seperates the top quality LiPo's from the cheaper variety. I highly doubt DJI spends the money for the best lithium cells when it comes to Phantom batteries. The temperature and cell imbalance at the end of a flight confirms this IMO.

    As for testing the break in theory in a controlled manner over a long period of time.... I thought I mentioned that I have already. I have accumulated enough LiPo's to fill two .50 caliber ammo boxes over the last 8 years, I would not be debating this topic if this was not the case. I doubted the break in theory as much as anyone else, until I proved it to myself. I used LiPo's from multiple manufacturers, from cheap to expensive, and I watched/compared their health using IR measurements over their lifespan. I tested various charge rates to see how it impacts the cell IR along with various discharge rates/SoC to see how the cells react during the first few cycles in terms of cell imbalance, IR, and temperature. I've spent enough time monitoring them that I have reached a point of realizing what they like and don't like. Everything I have seen confirms that they HATE being discharged fully during the first few cycles, which will have long term effects if done consistently during the first 10-20 cycles. Discharging to 50% has proven to keep them happy and healthy during the first few cycles, which maximizes their efficiency and capacity.

    In the end, I could care less if everyone doesn't believe what I believe, 'my beliefs do not require them to.'[/QUOTE]

    There's videos available that show the manufacturing processes.

    Maybe we all assume too much?
     
  18. silverstoned83

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    So who made these videos? DJI I'm guessing...

    How much can you really learn about the quality of Phantom batteries from a video of the manufacturing process that was taken by a biased party?