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6 flights at 50% on the batteries.....enough ??

Discussion in 'Pro/Adv Discussion' started by AIRNUTS, Nov 19, 2015.

  1. AIRNUTS

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    I have a new p3p and 4 new batteries, I been flying the batteries down to 50% they have been recharge 6 times each, is it safe to go to 30% discharge now or wait until the 10th recharge.
     
  2. bobmyers

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    It wouldn't be unsafe necessarily, but in IMHO do 4 more flights on each one, it is pure speculation to say that it will or wont help battery longevity-- but it is good practice.:D:D
     
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  3. AIRNUTS

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    Will do, thanks
     
  4. GadgetGuy

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    There is quite a bit of debate about this. I have never "broken in" any of my batteries by deliberately using them to less than full potential, and have 35+ flights each, on four different batteries, and they all still show 100% battery life remaining. I regularly fly all of them down to 15% or less with no problems. YMMV. :cool:
     
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  5. Noodle

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    As far as my limited knowledge on LIPO batteries goes, I don't think there is a set rule on how many flights you have to restrict initially to maximise the battery life. Airnuts, if you want to start draining your batteries down to under 30% from now, or you want to continue 50% cycle for another 20 more times, it's entirely up to you. Hope you don't have OCD :p
     
  6. GadgetGuy

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    LIPO batteries typically have 300-500 full charges in them. If you discharge to only 50% each time, you can double those number of charges, but you'll be cutting each flight time in half. Total flight time will be the same. Top off your batteries before each flight so you are always starting at 100%. Label your 4 batteries 1 through 4, and rotate their use in sequence so they are all used equally. Note that the smart battery automatic discharge feature will kick in and drop their charges to around 50%, if you don't use them for 5-10 days, depending upon your app setting. Get the $89 DJI battery hub to sequentially charge all 4 batteries unattended.
     
  7. Phantom751874

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    I did 10 then on the 11th went from 100% down to 8% on all 4 of my batteries. I need to check them again as I think I have a few with over 20 cycles now so I'll need to go from 100 to 8 on them again.

    Here's the deal when you go to 8%. Make sure you are ready for the drop after 10%. Default setting is for the P3 to land straight down after 10%. Caught me off guard at first. You still have control but you have to push up on the controls to maintain a steady height until you get to 8% then land.
     
  8. bobmyers

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    You probably should be deep cycling to 8 from 20 percent on the bench with the props off to avoid maximum amperage draw on the battery when deep cycling.

    This was a recommendation from a P3 vendor who has presented a couple of webinar's advertise on this forum about a month ago. The recommendation was to fly the P3 down to 20 percent and take it down to 8 % on the bench with the props off and at idle.
     
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  9. GadgetGuy

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    Good warnings! Are you able to ascend at all with full throttle, or does full throttle after 10% only maintain current altitude for lateral maneuverability?
    Also, while you refer to the default setting of Autoland at 10%, you can only increase that value. You can no longer decrease the Autoland value below 10% after the last few firmware updates. :eek: It is also recommended to remove the battery to first cool off when running them down, if you landed with 15% or less, which means you won't be able to take off if it reached 10%. Regardless, you can still run in idle until it reaches 8% inside or outside, or just turn the battery on. The battery gets really hot after flying itself down to 10%, and it's best to fully remove it to allow the heat to dissipate outside the quad and cool, before letting it get to 8%. Heat is the enemy of electronics. All this 8% discharge every 20 cycles does is properly reset the smart battery life values displayed in the app. It doesn't do anything to improve the life of the battery.
     
    #9 GadgetGuy, Nov 20, 2015
    Last edited: Nov 21, 2015
  10. GadgetGuy

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    I wish I could only land before reaching 20%. When I reach 20%, close to home, I feel compelled to fly right past home and fly around the neighborhood for a few minutes! Reaching 8% is no problem! :cool:
     
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  11. bobmyers

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    It is not helping the longevity of your batteries by running them down to those voltages every flight. Any cell voltage lower that 3.0 is a recipe for a damaged cell at some point.
     
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  12. Jbundy63

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    Exactly as with all my lipos , I have a lot of R/C stuff and running them under 3.0 volts is a killer, that is even mentioned in a lot in owners manuals of the product as well that uses this type of battery.
     
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  13. GadgetGuy

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    Thanks. I'll keep an eye on the cell voltages, too, which I don't think are dropping below 3.0 volts, but I'll make sure. So far, after 35 flights each, they are all still showing 100% life left. The 10% autoland feature is probably also keeping them from dropping below 3.0 volts per cell. Is there a remaining battery percentage that can be correlated to 3.0 volts per cell?
     
    #13 GadgetGuy, Nov 21, 2015
    Last edited: Nov 21, 2015
  14. GadgetGuy

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    I'm using an external battery mod now, where the internal DJI battery is supplented with two external 2800 mAh lipos, and even at 11% remaining in the app, the two external lipos are still at 3.7 volts per cell, as my charger for them displays per cell voltage during charging. The lowest I have ever seen on them was 3.6 volts oer cell. I wish the DJI charger also displayed individual cell voltages during charging. I'm also finding that the internal DJI battery is now much cooler when I remove it, than it was when flying without the externals hooked up. By itself, before adding the externals, it used to get really hot.
     
    #14 GadgetGuy, Nov 21, 2015
    Last edited: Nov 21, 2015
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  15. bobmyers

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    With regard to running the motors the remaining maH is the key to the P3 motors stopping -- at 30% there should be approximately 1250 maH remaining out of a possible 4450 (max charge) and the cell voltages will be around 3.7 with no motor load-- down to about 3.6 under full load. Drain them down to 8% under load and you are very close to falling under 3.0 volts per cell and under if you are at full throttle trying to keep it from crashing.

    You can dice it, slice it, cut it and chopped it any way your want -- but it all means the same-- at 10% the P3 is out of gas -- gravity will take over and there is a good chance that the battery will be damaged either by the crash or by cell damage caused by trying to keep the thing from crashing in the wrong place.
     
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  16. CONTROL FREQ

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    i have 6 batteries for my P3Ps and since yesterday, all of them are discharged (between 25 and 30 percent) and all of them have been charged about 40-45 times but i never discharged them to 8 percent.

    could i put the batteries in one by one at their current levels and run them down to 8 percent or should i charge them to 100 and then discharge them to 8 percent?

    thanks.
     
  17. Jbundy63

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    It's up to you, you can change them back up to 100% do your flight down to about 30% and then you can just leave your phantom on ( motors off) and let it run down to 8% It will take a little while, let them completely cool down a couple of hours and recharge back to 100% this should level the cells back out. I do mine around 20 charges, also the Go app will tell you when to discharge your batteries if you go into the battery icon and select history and it will tell you under the current status on what the battery is ( normal ) ( discharge ) ( self discharge - which is done while in storage)

    For whatever it's worth, I have over a hundred charges on my batteries and just now at 95 to 98% life left.
     
    #17 Jbundy63, Nov 21, 2015
    Last edited: Nov 21, 2015
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  18. CONTROL FREQ

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    thank you.

    i read somewhere that discharging your batteries with the motors off is not good for something inside, maybe the

    thank you for this reply.

    one thing tho, i read somewhere that discharging your batteries with the motors off has a negative affect. i think it hurts something internally... maybe the EMU? i can't remember.

    thanks.
     
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  19. Jbundy63

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    I myself haven't heard that or remember reading that, I do hover around close to me and low to help run it down, I would say 20% or so and then let it sit to the other 8%, it doesn't seem to take too long.

    But you have brought up a point I'm not sure so maybe someone will give input on that. Good question BTW!
     
  20. bobmyers

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    I put mine on the bench, take the props off and let it idle down to 8 %.. I put a small electric fan blowing on the P3 while it is discharging, keeps everything cool.
     
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