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P3 battery overheating issues?

Discussion in 'Pro/Adv Discussion' started by UnknownCaller, Jun 29, 2015.

  1. UnknownCaller

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    Has anyone besides me been experiencing major battery pack heat issues with the P3? Granted I have been flying mine long range 3 to 4 miles and I live in Florida but I am flying early AM and dusk when the temp is closer to 80 degrees out and my P2V goes through identical conditions and the battery is nowhere near as hot. I am thinking maybe the 4s battery being higher voltage runs hotter maybe?
     
  2. silverstoned83

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    I'm guessing you have less than 10 cycles on your P3 batteries? If this is true, you're comparing a fully broken in battery to one that is still in the process of breaking in. For comparison, I've been flying the last couple of days in 80-85F weather and I recorded a peak temp of 45C on the battery stat window in the Pilot App. Also keep in mind that I only drained it down to 50% in order to properly break in the LiPo since it still has only 5 cycles on it. Temperature has a lot to do with why it is important to properly break in a LiPo. After 10-20 cycles, you will notice the after flight temp begin to drop.

    As for the voltage being higher on the P3 batteries, that will actually reduce temperatures due to higher efficiency. More volts means less amps. RC heli pilots often increase the cell count of their power systems in order to not only gain more power, but to reduce the operating temp of their electronics, increase overall efficiency, reduce voltage drop, etc...
     
    #2 silverstoned83, Jun 29, 2015
    Last edited: Jun 29, 2015
  3. UnknownCaller

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    No these are not new batteries maybe 15 to 20 on one and 20 to 30 cycles on the other. I am begining to regret buying the P3 there are so many issues with it.
     
  4. UnknownCaller

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    Thanks for trying to help though.
     
  5. silverstoned83

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    It can take up to 20 cycles before the LiPo is fully broken in. How far did you discharge them during the first 10 cycles? Trust me, this is the reason for the temperature difference. An improper break in will lead to a higher internal resistance within each cell. More resistance will equate to more heat.

    No need to estimate, you can see how many times they've been cycled from the battery monitoring part of the Pilot App.
     
    #5 silverstoned83, Jun 29, 2015
    Last edited: Jun 29, 2015
  6. Dome

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    Really make me laugh each time I hear the legend of battery break-in .. It simply doesn't exist and it's a myth. Lipo battery need to "break-in" with 2-3 FULL RECHARGE, not 50% !!!
    When you first receive the battery, the best thing to do is to discharge until 3.10V/cell floor is reached, then fully recharge it. That's all folks.
    Instead, the minimum discharge of a Lipo cell is not a myth and it can cause damage to the anode carbon and litium ions not flow anymore as they would. But this is a problem if you discharge battery every time in this way.
    So discharge freely battery until 3.10V is reached and then fully recharge.
    Battery can be stored at full charge, half charge or whatever, this doesn't mean nothing to Lipo, except that you need to remember to recharge BEFORE they are completely discharged.
    What make the difference for the lipo end-of-life, it is the current (ampere) the flow in output and recharging current rate. P3A power supply probably gives battery many cycle more than P3P ps.
    Battery will produce heat in any case, becouse P3 ESCs are requesting lot of power (current in A), there's no way to avoid this. Clearly heat depends also from external condition (weather for example).
     
  7. silverstoned83

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    So I guess that all I've learned over the years in RC is useless then? Do you even know what internal resistance is, what unit it is measured in, and what it indicates? Considering that you don't even mention it in your post just goes to show how much you actually know.

    I have a pretty fancy charger for my other RC LiPo's which is the only reason why I have some experience with what to watch out for. Owning one of the most powerful LiPo chargers available to the hobby market forced me to learn everything you need to know about this battery chemistry. When you have 40A in charging/discharging current and parallel charging boards at your disposal, you better know what you're doing.

    I have done just about everything you can do to a LiPo, both good and bad. I'm just trying to share what I've learned based on my experiences. This is also what I've learned after talking to plenty of people in the business of manufacturing LiPo's and spending a lot of time in LiPo related forums. I guess they don't know anything either, right?
     
    #7 silverstoned83, Jun 29, 2015
    Last edited: Jun 29, 2015
  8. Dome

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    ... Wow! 40A nice for RC lipo.... we used 4 SCR water-cooled driven with HI-PO MOSFET at 55Ax4 .. but it wasn't for copters ...

    I think you know that resistance will grow for first 10-15 recharge and then stabilize, until battery get old and drop miserably (300-500 cycles depending from many factors).
    And just becouse you measured a little difference of int.resistance (in term of mOhm) you think the battery will last longer! It will benefit 1-3% more cycles if lucky! In the meantime the cells inside battery has different charatteristics between them needing better balancing! What you can achieve is better balancing in the DJI battery, that's ok, but modern battery are so perfect (teorically) with the material used in anode and catode! For example now modern Li-Cobalt moisture are so tiny and conductive that doesn't create an issue to internal res, also omitting the so called break-in period. I worked on Li-phosphate phisycs for professional UPS battery and we had no evidence of the phenomena. Resistence and ion flow does change in any case becouse the substrate of LiPo foils decay during time and it depends ONLY on the current (A) flow in/out and temperature. The chemistry behind it is an effect of a quantistic phenomena. Now it's boring enough to get in account all the C parameters in RC systems.
    For example lipo is now good to charge at ambient temp, but it's better to store in low temp. So for long term storage, it's not good to keep them fully charged unless you keep them refrigereted.
     
  9. silverstoned83

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    LiPo's benefit significantly from following a break in process, this is my opinion based on what I've seen in the past and I will continue to spread the word. I'm not sure why you seem to take my opinion offensively. Does my opinion have any chance of doing more harm to the LiPo, no... Does yours? YES!

    Being that this LiPoHV chemistry is so new, I'm surprised that you 'know' so much.
     
  10. Dome

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    @silverstoned83 I'm sorry if I give the impression of be offended !! No I'm not and I don't want to offend nobody.. I'm not natve english language, so may be sometimes I use wrong words or expressions!

    The Lipo battery concept (at that time were called "Li-ion battery") exists since invented by John Goodenough (1922). In 1970 someone realize the proof-of-concept, but the problem was with charging temperatures: they need more then 60-70°C to start the back-avalanche effect between pure litium and carbon...ouch !!.... Recently ('91) Sony get on li-ion and she found an interesting solution to fake the ions with moisture of Litium Metal oxide (like LI-Manganese and Li-cobalt). For correct explain, the anode is now graphite and catode a Li-metal oxide like.
     
  11. F6Rider

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    My batteries do get pretty warn, not excessively so but much more that the P2 batteries did. With the higher power motors the amp draw is higher so more heat. I run them pretty hard (high speed and full power ascents) so am not surprised by the added heat. When finished with a run I do not place the battery back in the case slot (cooking effect) but leave it out to cool first. I do follow a break in period, can't hurt and might help. I store my batteries at 40% and fully charge only right before a flight session. Is all this needed, not sure as I am not a battery chemistry expert, but anything that will prolong the life of a substantial investment is worth a try.
     
  12. OldFlyer

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