Flight time of a 3DR robotics X8 model 2013

Posted by Nader on July 20, 2015 at 1:57am

Hello,

I am using a 3DR robotics X8 model 2013, with 2 batteries in parallel( each one: 4200 mAh, 3 cells. I get a flight time of 7 minutes (voltage drops to 11.1 V). I always have an additional weight of 300 grams. I need more flight time. Do I have to change the batteries? buy a new one with 10000mAh.

Thank you

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Replies

    • Nathan Dean > Gregg February 15, 2016 at 11:41am

      Im using the 10,000 4 cell lipos and getting around 16 min with a 3 axis gimble and go cam. Flying at 5280 ft which cuts down flight time.

      16min?! Seriously??

      I've got the same setup and I've never gone longer than 11 min. (avg 9.5 min). Low battery is a continuing problem for me.

      I've had the rig crash in the middle of an autotuning session because battery failsafe was evoked. The failsafe is set to 14.1 volts but when I put the spent battery on the charger it's always way higher ~15 or more. I'm starting to wonder if the APM parameters are interpreting the voltage incorrectly. Specifically BATT_VOLT_MULT and BATT_CUR_PIN

      What am I doing wrong? What should I check for?

      Thanks for the help.

    • DG > Nathan Dean February 22, 2016 at 3:29pm

      Do you have a log? 

      Did you calibrate the voltage? 

      Personally I use a HobbyWing voltage sensor connected to a X8R, X6R and X4R to check each cell voltage independently and report to the Taranis tx.

      BTW, I just bought a X8 frame kit from 3DR and plan to give it a go. . 

    • DB > Gregg July 21, 2015 at 5:55pm

      What's your GTOW?  How far do you drain your battery? 

    • Gregg > DB July 22, 2015 at 9:31pm

      Dont really know what GTOW is but I never drain the multistars past 20 percent. They are not the best batteries and cant handle a big drain with out puffing.

  • DB July 20, 2015 at 6:43pm

    According to this calculator, one option is increasing the battery size. The calculator says you gain about 2 minutes for every 2000 mAh of capacity added at 3S. However, 4S seems to perform a bit better for this vehicle. Check out the links below:

    - Your version (assuming stock X8, changing the batteries, and your 11.1 V is when under load):
    http://controls.ae.gatech.edu/dbershad/EMSTAirTimeCalculator.html?&...

    - Stock X8 (matches reported flight time of 15 minutes):
    http://controls.ae.gatech.edu/dbershad/EMSTAirTimeCalculator.html?&...

    • Nader > DB July 29, 2015 at 10:44am

      Hi sir,

      Thank you for your response. These are some specific details about my quad X8 (model 2013):

      1. weight of the quad: 1763 grams

      2. weight of 2 batteries (each one: lion power lipo battery 4200mAh 3s 30c): 572.5 grams

      3. payload: 270.5 grams

      4. flight time: 6 minutes (voltage drops from 12.34 to 11.02 V)

      I am planning to buy a new battery (multistar: 4S 10000mAh 10c 804 grams)

      Do you think I can get a flight time of 10 minutes?

      Regards

    • Nader > Nader July 29, 2015 at 11:57am

      In addition:

      the quad flies vertically to reach a height of 100 meters and then come back to home position (climb speed of the quad: 0.5m/s and descent speed: 0.8m/s)

      Do you think I got this small flight time since the climb speed of the quad is too small?

    • Darius Jack > DB July 23, 2015 at 6:11am

      Why do you keep promoting your calculator ?

      It doesn't make sense to input 10-20 fuzzy logic data to get any general estimate on flight time.

      What matters is battery health live testing data delivered via telemetry and have

      control station run script to calculate flight time left.

      Just imagine to have your car data, speed injected into your calculator to get estimate on a range to drive in km/ miles.

      Not a realiable technology.

      Ok, your calculator is a good marketing , business tool to collect data on drones in operation by users with IP assigned to offer them upgrades, extra parts and make real money on tuning of their drones to extend flight time.

      Your calculator should be upgraded with real science tools to process uploaded log files

      to verify theory against real practice.

    • DB > Darius Jack July 26, 2015 at 11:21am

      Why do I keep promoting it?  That's an easy one to answer:

      1) so people use it and give me feedback and I can improve the math where it is needed 

      2) to provide more tools for us to use to help our community design vehicles and defend the parts choices they make

      3) I'm working on a Ph.D. in performance analysis and prediction and this is also my hobby

      The rest if your comments.. not sure what you mean.

      Fuzzy logic?  Do you know what that word means?  I have no fuzzy logic anywhere in my code nor do I need it.

      Battery live testing what are you talking about?  I want user's data because I can't afford to buy thousands of combinations of propellers and motors and test them myself.

      "Just imagine to have your car data, speed injected into your calculator to get estimate on a range to drive in km/ miles."

      I don't have to imagine this - my car does this.  And yes, it is reliable.  How is this even relevant?

      Thanks for the marketing advice, I'll consider collecting data and IPs to make money in the future.

      Real science tools?  I'd be happy to discuss real science with you if you have any specific concerns about the lack of science in my software.  Your vague criticism is not helpful.

    • Tony K > DB February 22, 2016 at 11:58am

      I would just ignore him like most people do here. He is out to lunch. 

This reply was deleted.