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Understanding Lithium Polymer batteries

Discussion in 'Beginners Drone Forum' started by Bartman, Jul 31, 2013.

  1. Oceans Eleven Wassup?

    Oceans Eleven

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  2. Kratos Member

    Kratos

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  3. I hope you are getting everything for your build in one shipment. :eek: HK is way expensive with their shipping. It sometimes is almost half the cost on smaller purchases. I just bought two 610 mah batteries from them. The batteries were $3.85 each and the S&H was $6.10:eek: I have shopped around just to avoid their high S&H:D I know, batteries. But at HK, EVERYTHING costs a lot to ship. Then you have to worry if the stuff will even work. They are reasonable with refunds for bad stuff as I have learned from personal experience, except they don't refund the cost of S&H.:confused:o_O:(
    Their Turnigy Multistar stuff is pretty top notch though.
     
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  4. Kratos Member

    Kratos

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    Thank you for your reply, it is answer that I am searching for. This is my first build so I was ordering separated props... 2 dollars doesn't mean something but I ordered something bigger shipping is really big. I was trying to order item 30 dollars and shipping is 30 dollars too, I didn't see that after I pay I saw that and immediately channel order. They refunded me everything but didn't bring me back my points. I am trying to avoid HK but for some parts it is not possible. This I charger looks good to me. Anyway props, receiver, battery, turnigy motors, Rc controller, i charger, ESC, I think I will order from HK, if you have better place please suggest me :)
     
  5. I don't know. I sort of know what I want then search for it with the word ebay after the item I'm wanting. Then I look for the ones with free shipping from inside the U.S. (But I know you may not live here in the U.S.) HK is usually a last resort for me but there are times where they have what you need and no one else does. Like the batteries for real cheap I mentioned and the FPV quanum headset I bought from them also a bargain at $29.95. After S&H it still only cost me $37.95 with $2.10 discount points included. It's pretty nice after I fixed the janky wires they had on it. So they aren't ALL bad. Still, shipping was like 1/3 to 1/4 the cost on that one. It was around $10.10 or something like that.
     
  6. Motopreserve Drone Enthusiast

    Motopreserve

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    Are you ordering from the U.S. Warehouses? I don't recall the shipping being so bad from inside the U.S. But you have to make sure you choose the proper method - since they seem to up charge for "faster" services.
     
  7. Kratos Member

    Kratos

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  8. Yes, I order from the U.S. warehouse in Arkansas. I always use the lowest cost option on their ordering page, preferring to wait rather than pay. HK is what I would consider one of the, if not THE, highest shipping chargers there is out there.
     
  9. 2 people like this.
  10. Oceans Eleven Wassup?

    Oceans Eleven

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    LOL! That's pretty funny. You a comic? ;)
     
  11. Kratos Member

    Kratos

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    He is not, I almost made wrong turn with naza... naza m-lite is not compatibile with zenmuse H4-3D....
     
  12. I try and make people laugh if possible.:D But I was telling Kratos the truth there. I'm not exactly what you would call a DJI admirer. That's my story and I'm sticking to it.
     
  13. cleamon Member

    cleamon

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    When you talk about special care for "storage", what time frame are you considering? A week, a month, more? Is it advisable to keep batteries at "storage" levels between (weekly) sessions? Just top them off the day of (or day before)?
    My tendency is to charge them as soon as I get home, so I'm ready to go on a moments notice.
    Also, since I'm just starting out, all of my batteries are small single cell jobs. Do I need an advanced charger, or just the little charger that came with the quad? I also have purchased package of 4 batteries that came with a charger that charges them all at once. Is that sufficient?
    Thanks.
     
  14. fltundra Member

    fltundra

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    They always need be at storage level when not in use.. I never charge a pack more then 12 hours before use, and that's on rare occasions. 98% of the time I charge early in the morning for that days flights.
     
  15. fltundra Member

    fltundra

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    For the cells your flying now, i wouldn't worry to much about them. It's when you move up to bigger lipo's, that you will want a good charger.
     
  16. cleamon Member

    cleamon

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    Thanks, that's good info to know. As for that last comment, I'm currently flying as often as I can so the 12 hour period rarely occurs. At least until the "honeymoon" is over. :) Thanks again.
     
  17. TheCrey Member

    TheCrey

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    Hi,

    first, nice Thread, very nice and informative Postings here.

    Thanks for that.

    As i am new to Qaudrocopter and all the areas around it and i am in the state of reading and trying to understand all.

    And this Thread helped a lot.

    But one thing i am not quite sure. I just can understand it well, maybe because of the lack of knowledge regarding electricity, to be honest i am sure it is because it the lack of knowledge ;)

    I am not getting the concept full of the C, discharge rate. I know how to calculate it etc. But how do i know how much i need ?

    What i mean is, how do i know how much AMP my Motor do need?
    I only have the 1000kv information on it and the props info. Also the max Amp of the ESC (in my case it will be 30AMP each)

    So, from what i understand, a i am building a Qaudrocopter, i have 4 ESC with 30 AMP each, so they can use 120 AMP max.

    Because of this i need a LiPo with i would say at least 3000 mAh and 50C = 150 max Amp

    Am i right at this point?
    What would happen if i have a 3000 mAh and only 25C = that's only 75 Amp, too less.
    I am guessing, besides the effect the battery will not hold long, the motor will just not spin enough, it will be very slow maybe, maybe not enough power to lift the quad at all ?


    What about the Motors, can you give them to much AMP ? I am guessing, to less AMP they will just not be strong enough to lift the quad.
    What i mean is, for any reason the ESC is able to handle 60 AMP, Battery as well, and you throttle full, will the Motor be able to handle this? Does it depend on the Motor?


    Also, from what i understand, hovering will use less battery then max throttle right ?
    So, as i just want to do some nice smooth and slow aerial video etc. the flight time should be longer as with a FPV racing background.
    Of course the weight will also count, but in general, just for my understanding.


    Sorry if some questions sound stupid to you, i really tried to answer them by myself and while reading tons in articles and forum post.



    TLDR;
    What happens if you use more AMP then the Battery can handle?
    ESC, does it use the full AMP all the time?
    Does the Motor have a max Amp ?


    Regards
    TheCrey
     
  18. moonpie57108 Member

    moonpie57108

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    The motor/prop combination will determine how many amps you need. The ratings on the ESC and Battery only serve to tell you how much that piece of equipment can handle without causing damage in theory.

    This rating would not determine what you need, but it gives you an idea of what the ESC can handle. If you were to push these ESCs to say 40 amps for too long, they might simply catch fire or shutdown.

    The battery is capable of delivering more than 25C in short bursts but depending on the quality of the cell and length of burst, it can cause permanent damage to the battery when doing so. The motors will spin up just fine. Too low of a C rating, the voltage will sag and you will lose power sooner. One thing to note, many of the C ratings are a joke. If you pushed a 25C battery to 25C it might fail, it might fail at constant 20C.

    This is the part where you will want to be careful as you are looking at it sort of backwards. The motors are the driver in this equation. When you give the motor full throttle, based on its capability and the size of the load, the motor will try to achieve full speed with that load. If it takes 50 AMPs to generator the power required to spin that load, the motor will try to pull it. Your battery might be rated for 10 amps and your ESC rated for 15 amps and your motor will still be trying to pull 50 amps. This is one way to fry a battery or esc or both.

    Each motor is rated for x amps. I will using KDE 2306 2000kv as an example. The motor is rated to handle 24 AMPs for 3 minutes straight, meaning it shouldn't melt, over heat, or otherwise destruct in those 3 minutes if it takes a constant 24 amps. However, some of the prop combos on this motor could pull 30+ amps. But this depends on the prop you use. You could use a prop on this motor that pulls 8 amps at 100% throttle, your 10 amp battery and 15 amp esc example would work just fine. By just changing the prop load, you could jump your load to 30+ amps

    Edit: AMP rating on a brushless motor is like redline on a car. Its not that it isn't capable of going beyond redline, but holding there too long will causing overheating and damage.

    A power curve on the motor (throttle percent to amps of a given load) is exponential. As a general estimate, a 50% hover situation will use 1/4 the amps of max throttle. So the lower your average throttle throughout your entire flight, the longer your flight can be.
     
    Last edited: Sep 5, 2016
  19. TheCrey Member

    TheCrey

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    Hi,

    wow, moonpie57108, thanks!

    I can work with this.

    Regards
    Crey
     
  20. betty Member

    betty

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    Thanks for your sharing!
     
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