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  • Hello Martin and others,
    I went to the DJI website here in the United States and it says that the Inspire 1 uses one of two batteries. The standard is the "Intelligent Flight Battery" TB-47 that is a 4500 mAH 22.2 volt LiPo 6S High Voltage Battery and it weighs in at 570 grams. The optional battery a TB 48 is just a 5700 mAH 6cell LiPo that weighs in at 670 grams. I did not see a single model of DJI's that uses anything but a LiPo battery at least not in our market here in the United States. If this is different "down under" than I would be very curious why they would use two different types of batteries in a standard product.
    The High Discharge LiION batteries I am testing currently are supposed to last 10,000 cycles before wearing out according to the manufacturer. Our Tesla products made here are powered by the 18650 cells and they claim 10 years of every day cycling of over 50%.
    The information I have read suggests that the current LiPo batteries are designed to last way more than just 100 cycles. liION cells are useful and have lots of places where they are commercially used, I just haven't seen one used by a quad. I also don't believe their cycling claims.
    liPo cells should be taken care of slightly differently than LiION cells in that they are a bit particular in the way they are used. I have to balance even the two cell units I used in my ducted fan model jet or the life of the product will be cut short.
    The charger I use is one that monitors the temperature of the cells while charging. This keeps them from experiencing "Thermal Runaway" which happened a lot in the early days of LiPo. I have not put my LiPo's in the flame proof bag in years and have never had a problem with one fortunately.
    Lithium Ferrous batteries are becoming more popular and I use them in my 2 Motorcycles. They weigh less than a pound and are rated at 12Vdc. These cells will become used more widely in the years to come.
    In the early days of model aircraft they used NiMH cells to power them, very cheap, very light and have a few of their own problems.
    I did not mean to step on any toes but here in our market LiPo is the most popular method being used. Their weight, power output, cycling ability and cheap initial cost makes them an ideal choice for flying UAV's. To make them last you have to pamper them a bit more than a LiION cell when you charge and discharge them. Using a 2200 mAH 11.1 volt battery my Blade 400 will fly for twenty five to thirty minutes with my camera attached.
    If the 5000 mAH battery were designed to put out 250 amps I am sure they could do it reliably. Any battery that is abused will self destruct. I have started cars with 3000 mAH LiPo batteries, one was a 7 liter, high compression Corvette engine. With proper care and wiring to suit it no problems. I will admit I did it in an enclosure just in case!
    Good luck and May you have many happy hours flying your UAV's.
    Under Construction
    • Moderator

      Hi Christopher, I have tried to modify the misleading comments I wrote regarding the DJI inspire and Li-ion batteries but it just posts everything to the end of the discussion. My apologies.

       The fact is that most uavs do not require prolonged high current drain unless very large, heavy or both. Even in these cases li-ion battery packs can be assembled to cater for most requirements. It is also a fact that li-ion cells have a higher capacity to weight than their lipo counterparts. Standard li-ion cells are not suitable, there are specific high discharge cells that are. We have tested lipo batteries, most claim 20-50c. Care to try a 5000mah lipo at 250 amps and see what happens? It's not pretty! Then we get to cycle life, even with good care and gentle discharge most lipo batteries are on the way out at 100 cycles. Li- ion is good for at least 500 if looked after the same and potentially much more. I will not tell you that li-ion is the battery for all machines but they are more than capable for most and with significantly better performance.

    • Moderator
      I never said it was standard but it has been done! Cycling of li-ion are much better than li-po, I too would laugh at 10,000 cycles regardless of the draw- but 500 to 1000 are easily achieved. Most liPo batteries don't even get close to that. Manufacturers make a lot of claims but only real world testing is proof. Lipo is popular but mainly because no one is offered another way. Li-ion are lighter (or more power for the same weight), cycle much better and are just as cheap. We have a huge flight time increase with our battery packs for the same weight as lipo and much greater longevity. How many 3000 mah lipo packs did you use to start the corvette and how were they wired? How long did they draw and what was the current? We tried a 5000 mah lipo at 250 amps, it's stated c rating- it ceased to exist in seconds.......
    • Hi,

      Where can I try/purchase one of these li-ion batteries? I would love to try a 9000 mAh 4S li-ion battery. I am currently using 5200 mAh 4S lipo batteries weighing 505g and I'm getting about 10-12 min flight time.

      I recently experienced a crash where my quad dropped out of the sky and I believe it was due to a bad cell in the battery. My quad weighs 1.75kg and consumes 20-25amps from hover to about 15mph, and up to 45amps at 50mph.

    • Moderator

      Hi Robert,
      We are in the process of getting set up to sell these packs online. However we want to finalise the manufacturing and testing process in the factory completely before going live. There is nothing more important to us than 100 percent confidence in our products and the ability to process orders in a timely fashion. We have flown many hours with these packs and they have behaved flawlessly, the only problems were finding a reliable supplier of grade a cells (there are many fakes in circulation with bogus specifications). Having gone directly to the manufacturer and negotiated a supply we are in a position to certify all the packs we make. If you are in need quickly then any local electronics specialist should be able to help as long as they understand your aircraft requirements. We do hope to post here on diy drones when we start the website but I will be asking permission from the moderators first as it is essentially advertising and would have to be deemed of interest to the community. For your aircraft the 4s 9000mah would work fine. We will be publishing all the info on the website so people can choose their own packs that suit them best, choose the pack temp telemetry sensor option etc,  or we can advise if required.

    • Thanks for the info. I've been working with Forrest and a few others to develop lighter frames. Forrest holds a world record for his quad flight using Li-ion batteries: http://diydrones.com/profiles/blogs/world-record-flight-achieved-us...

      I've been working on a lighter, stiffer frame replacement for the QAV400: http://diydrones.com/forum/topics/qav400-mods-to-increase-flight-time

    • Moderator

      That is some brilliant work! looks great. Our head engineer has built a full spec 650 sized quad that is ridiculoulsy light, combined with the li-ion battery packs its hilarious, you shut the throttle and you nearly have enough time for a cup of tea before it comes down. The quad you have that weighs 1.75 kg, is that the AUW?, the current draw seems a little high. If I can be of any help, please feel free to PM me.

    • Moderator

      Having seen where you are Robert, Batterybro in the US would be a good place if you are in a hurry.

  • The primary reason that we use Lithium Polymer batteries instead of the Lithium Ion batteries is that our little flying friends can require very high amperage withdrawals at times. LiPo batteries can deliver the higher amperage loads where a LiIon battery is very limited as far as currents go. There are specific LiIon cells that can handle discharges up to 30 Amps at 3.7 volts but they are not the normals cell. It is possible to pull 50-60 amps at 11.1 volts out of a 2200 mAH LiPo cell without damaging the cell.
    There is also the weight and size issues. For the size and weight there is little that can compare to the LiPo batteries we use. The standard 18650 LiIon cells that are common and cheap would require a package several times the size of my 3 cell battery that I use in my quad.
    I just checked and the E-Flite 3s 11.1 volt 3000 mAH is labeled that it can support a maximum of 90 amps continuous. I work with batteries for a living and that is just incredible for its size and weight. Trying to use your Milwaukee tool cell (LiIon) just can't match the incredible loads our air craft need to fly.
    Use a good charger and make sure that you balance all the cells in the pack you are using. I use a little plug in device that shows the individual voltages of the three cells (in my case) as well as the total voltage of the pack. It is a simple way to keep the battery as healthy as we can. Also buy a decent charger that can balance as well as just charge. The one I use also discharges the cells as well as balancing and charging. I cycle my new battery packs two or three times before I fly with them.
    I hope that this helps with the battery questions regarding the LiPo and LiIon usage. Fly with LiPo and use the LiKon cells in your tools or telephones. Good luck!
    • . It is possible to pull 50-60 amps at 11.1 volts out of a 2200 mAH LiPo cell without damaging the cell.

      550-650W from just 3 LiPo cells ?

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