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I have a big issues in the way DJI ask you do deep cycle your batteries.

Discussion in 'Inspire 1 Discussion' started by jhardway, Aug 23, 2015.

  1. jhardway

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    I find it very crazy that there is not a DJI produced accessories out there to help deep cycle batteries. They are asking use to fly our basically down to the batteries limits. On many levels I am not a fan of the technique. One is adding useless flight time on the aircraft, where you are putting more time on the motors, FC, Camera - which already runs hot, internal cooling fans, etc. If i wanted to take the all the gas out of a Cessna with 20% gas in the tank I would not sit on the runway and run the motor until it shut off

    The second thing is on the battery itself, you are taxing it down to its limits, I am not sure if you have felt the batteries after you fly it down to 5%, the are usually fairly hot, above 50 degrees Celsius (125F) by touch I feel they are much hotter then that.

    Why is it they have not come up with a small device that you can use to draw the proper safe voltage down until it shuts off. I would purchase that, considering I have five batteries.

    Right now the best technique I have found is to do some flight an then run a battery down to about the 5%, at that point you use it to recharge the controller, In most cases it will lower itself to the shut off point.

    Recently i have seen a few off market discharge device out there, but why has DJI not taken care of this, It puzzles me, why they have not done anything to help in this situation.
     
  2. JimPA

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    I have 4 batteries and I run them down using a Programmable DC Load and create a 4-6Amp load and let the battery shut itself down. This still takes some time if the battery has a full charge. Sometimes I'll fly down to 20-25% and then use the DC Load to take it the rest of the way down.

    After the above process, I normally have to let the battery cool down for 30 minutes before it will take a charge. You can start the charging process, but the battery will normally error out on over temp. It will continue on it's own after cool down.

    But, I agree, it would nice if DJI had a device that automatically does this.

    I'm toying with the idea of automating the process and using some large power resistors and creating a device to do this in conjunction with the stock charger. Should just take a uController, a relay, temp sensor, and current sensor.
     
  3. Derfmen

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    I use two 24v bulbs (tail light bulbs for a truck) plugged into the battery after I fly down to 15%, it takes approximately 20 minutes till the battery shuts down. I've done this since day 1 and

    I have had zero battery issues.
     
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  4. jfro

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    Do you think using 4 bulbs, assuming 7 minutes after your 15% level would be to fast, ie too demanding on the battery? I think it would still be less than the draw while flying an Inspire.
     
  5. JimPA

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    It all depends on the current load the bulbs place on the battery. I'm not sure what the draw during flight is, but I bet it's quite a bit. If you can drain 80% while flying in 12-15 minutes, I'm guessing taking the same 15 minutes to drain the last 15% is much less of a load.

    When draining on my DC Load I set the current to about 6 amps. That would be about a 1C discharge rate. Many LI-Poly batteries would be ok with a 10-20C discharge rate. 1C is the rating of the battery. So for the 5,700mhA batteries that would 5.7Amps.

    I don't see any issue with using some lights, other than not knowing what the actual discharge rate is.

     
  6. Derfmen

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    the bulbs I use draw 4.8 amps, it works for me, I really don't like discharging the way DJI says to do it.
     
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  7. sdjackaerial

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    This is so cool. Would you please post pics of what you made to do this? I'd love to make this for myself. Thank you! Great innovating!
     
  8. Steven Powter

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    I have over 600 cycles on my batteries ... some batteries have been cycled 120 times.... i always fly my batteries down when recycling them.... i have had no issues....
     
  9. jhardway

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    Derfman

    you said you are deep cycling basically every time you use a battery? I am curious on how many cycles you have on your battery.

    I like your little draw device,
     
  10. jhardway

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    skjackaerial - As I have been looking for a better way to deep cycle these things I found the following on amazon, very similar to Derman's but more produced with sometype of circuit board involved. They say its for a phantom but over all they are produced for a 3-6s batteries. cost is $19.

    [​IMG]
    Have one coming over the next few days, when I get it I will let you all know my thoughts.
     
  11. Derfmen

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    I'm sorry, I didn't mean to make it sound like I deep cycle every time I use a battery. I fly my batteries down to 15% and recharge, I "DEEP CYCLE" every ten (10) recharges as the DJI manual says to. I ALWAYS make sure my batteries are at 100% before I take off. I got my I1 in March and have approximately 150 recharge cycles each and 15 Deep Cycles each. I have 4 batteries and have never (knock on wood) had a battery issue.
     
  12. jhardway

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    Chnjab

    I know about the smart station and at some point i was looking to get one but at the time they were hard to get a hold. The other problem I have with them also is size for traveling reasons. Over all although they are a third party vendor making a product for a need out there, I am all for them supplying the market, my issue is with DJI and it should not be up to me to go purchase an another product for $300+ for a battery specific device.

    Especially when there is a very simple and quick fix, other then flying the battery down on the copter. When you bring a battery down to that level it should be OK but when you are having it controlled by a smart chip that has and auto shutdown ability in it, that cause a lot of concern with me. Some other concerns are with battery health, temperature, and safety.

    I have a 333 exemption and although it is a documented situation about how DJI tells the operator's how to proceed with a deep cycle, the FAA is OK with it, I believe mainly because they are so overwhelmed.

    I feel if the FAA figured out that in-order to do a deep cycle you are being asked to fly the copter's battery down to below 5% or leaver you copter running on the hours on the ground. They could have an issue with this especially when it jeopardizes safety for current flight or future flights to come.

    cheers all and thanks for all the returning post so far on the thread, they are very helpful.
     
  13. jhardway

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    I got my stuff in February and two of the 4 I got at that time I am having some issues with, they have less then 40 cycles on them and have been recycled at the proper times, I actually contacted DJI and got an RMA, we'll see how that goes, I have total of seven batteries so I am not to concern about see these coming back in 4 months.
     
  14. Steven Powter

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    The simplest way and the fastest way to cycle your battery... is to fly the battery down... bring up the battery display... over ride the auto land .. no problem... i have 12 batteries... 3 DJI chargers... never had a problem.... you don't need charging stations... buy some extra batteries instead....
     
  15. Carlo

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    I purchased Five of these in a version 2 for 21.00 @ Infinity Hobby
    not for the Deep Cycling, I use the SMART Power Charger for that, I have 9 TB48's and sometimes I don't use all batteries this unit will discharge to 40% for storage something the SMART Charger doesn't yet! key word is Yet as maybe in the future it will be programmable via firmware to set the controls.
     
    #15 Carlo, Aug 25, 2015
    Last edited: Aug 28, 2015
  16. jhardway

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    My approach is once I get one of these units i will see how far it will bring the battery down, if it goes to 3.5 then when at that point it should be a matter of attaching it to the remote and letting it run down the rest of the way, or I can string up some type of bulb like Derfmen that does not have a circuit to cut off the input, and let the battery shut it self down.

    I like to play around with stuff so I'm interested in getting the little unit and see what it does. As of the SMART Charger I am in to having one but until as my work flow is moving at a better pace I'm not going to invest in one. Enough of that, when you start chatting about business plans then your probably at a good spot.

    again I like to thank everyone on the thread, its been a good for me just to bounce the information around.

    best
     
  17. InspiredOne

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    Carlo, forgive my ignorance. Can you, please, provide a link to the item you are referring to as the "SMART Charger"?

    Thank you!
     
  18. Scotflieger

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    InspiredOne likes this.
  19. InspiredOne

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  20. Bham Jack

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    I have ordered one also (branded jrelecs but same photo and numbers on ic board). I note the primary function is to reduce batteries to "storage voltage" when you are letting the craft rest more than a couple of days (to preserve batteries). The full discharge is a secondary function. Best advice from forum scans for full deep discharge seems to be let this device run battery down (approximately 5.5v) then use the battery in the craft (simply turn on and leave it to eventually do its own low battery shutdown). I assume that for this final step there is no need for the RC to be connected to the craft (comments)?

    Critique welcome, will report results later.