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Quadcopter Maintenance 101

Quadcopter Maintenance 101

Post by Jayrald Rabago

Aloha FlightClub FPV! Hope you had a great weekend out flying from a race, or a good time with your group, or touring the world with your drones. Before settling to review footage, don’t forget to give your gear some TLC. This can prolong the life of your gear and take care of any issues before your next FPV session. In some cases, you may have an opportunity to fly on the whim and taking care of things now can allow you to seize that flight time.

It takes time to do maintenance checks and bring batteries to safe storage voltage. In this article, I hope to layout my version of a recommended maintenance routine, as well as some additional things you can consider doing once you are in a good routine.

Coming up with a maintenance routine isn’t clearly laid out by the manufactures of our drones. For the most part, we build our own drones and may know it inside and out. In other cases, they are built as ready-to-fly or bind-and-fly kits. With this knowledge, we can take preventive care steps to ensure our drones continue to fly as expected.

In this article, I will go into more details on the:

  1. Highly recommended maintenance
  2. Maintenance to consider doing
  3. Five checks after maintenance and before your next flight (or before your first maiden)

1)    Highly recommended maintenance – These are highly recommended maintenance routines you should do after every FPV session.

  • Batteries:
    • Check batteries for any damages
      • If batteries show physical damages, check their internal resistance (“IR”). Batteries having a stated C rating of 70-100c may have cells with IR of around 1 to 10 depending on battery brand and charger you are using to measure IR. In my experience, when cells have IR that vary by more than 2mΩ between cells will give less than desirable performance.  I will normally date my batteries and their measured IR values to keep track of this. Damage and heavy use can cause the IR difference in cells. Catching batteries in this state can help prevent damaging other batteries before parallel charging.  You can check battery resistance with a simple multimeter.
    • If you don’t plan to fly in the next 3 days, discharge all batteries to storage voltage ranging between 3.8 – 3.85 volts per cell
      • I found that batteries have kept their IR closer to the stock IR when the batteries are not kept fully charged for long periods of time. The consensus in the FPV community is that the batteries performance should stay stable if left fully charged for 1 week or less. I do notice that batteries charged the night before perform better than when they have sat fully charged for more than one day.
    • Properly store batteries in a safe place such as: fire proof container, outside over concrete, near a bucket of sand, or anywhere that can contain an accidental fire and protect the rest of your property.
  • Quads:
    • Ensure the following is clean of debris: Electronic connections, wires, motors
      • Sap, and any liquid stew from chopped greenery can wreak havoc on your builds.
      • Rocks and metallic debris find their way into motors. For a quick clean, I will use a can of air used for dusting. When I do find time, I will take apart the motor bell and meticulously clean out all the debris with a Q-tip.  
    • Check all wires for any cuts or nicks that may expose wire and create a short
      • I generally address this by simply wrapping a small piece of electrical tape around the cut wire. I’ve also used a dab of liquid electric tape to seal the cut.
    • Check for any loose parts
      • I will pull and tug at the arms of the frame to ensure the frame is secure. The screws that will usually come loose first are: motor, screws holding in the arms, and the plastic m3 nuts on the top of the electronics stack. Also ensure your FPV camera screw is tight enough to prevent your camera angle from changing in a hard crash.
    • Transmitter
      • Charge your transmitter. Most transmitters come with a NiMH, LiFE, or other batteries that can safely hold a full charge over a longer period than an LiPo battery can. By charging your transmitter, it tops it off for the next FPV session and eliminates one thing for you to worry about.
        • If you have a Taranis X9D, there are many aftermarket battery options. One option is the Turnigy Nano-Tech 1500mAH LiFe 3S. This battery will fit comfortably in the Taranis and have a similar run time as the original NiMH battery. Additionally, since it is a 3S battery, it can easily power external receivers such as the TBS Crossfire module.
      • Googles
        • Ensure your goggle is powered down. Its sad to admit, but I have left my goggles plugged in after a session and was wondering what the beeping was coming from the trunk of my car as I drove home.
          • If plan to fly within the next week, I will normally top off my goggle battery again. Amazingly enough, the Tattu 2500mah 2s was able to last a whole day of flying and the long drive home from the situation above.

2)    Maintenance to consider doing – These are maintenance routines that you can consider doing when you have more time.

  • Refresh spare parts kit
    • If you had to perform a couple of repairs on the field or helped someone out by giving them some parts, be sure to re-up on your spare parts kit.
    • Check for deals at your local hobby store and online for deals on items that you may be low on such as spare arms, video transmitter (“VTX”), camera, etc.
    • Double check your tools
      • In this hobby, you can feel a real sense of comradery. Ask any question or cry out for help or frustration and you will have a group of people huddled around you offering their assistance. So, tools can get misplaced. It’s best to know you’re missing a tool at the end of the day than at the next FPV session you have.
    • Reflect on your flights and consider things you want to change about your build such as the factors listed below. By reflecting, you can prepare to purchase the items in bulk at the next sale and configure your drone for the next session:
      • PID tuning
      • Rates
      • Motor and prop choice
      • Frame choice (True X vs Stretch X)
      • Arm size (6in vs 5in)
      • FPV camera look (CMOS vs CCD)
      • Video signal/interference

3)    Five checks before plugging in your battery for the first time/after maintenance

  1. Connections
    1. Check for shorts
      1. Physical check looking for bridged connections. The most important type of bridge to look for is a bridge between the three ESC wires. This bridge will break an ESC even when a smoke stopper is connected.
      2. Multimeter continuity check will let you know for sure if there is a short between two points.
  1. Plug-in connectors
    1. Ensure the camera and VTX plugs are securely in place
    2. UFL type plugs for VTX are notorious for being unplugged during a build if pulled on with some force.  Use some Bondic to reinforce the UFL connection.
  • Ensure an antenna is connected to the VTX when powering on the drone. Not having an antenna can cause the VTX to overheat and ultimately fry.
  1. Screws
    1. Double check that all screws are securely holding the frame and all electronics are firmly in place. The screws that I find most critical are for the: motor, flight controller, and arms.
  2. Motor order and rotation/orientation
    1. Ensure motor order and rotation/orientation is correct based on what Betaflight is expecting. Check out the motor remapping article for more info Betaflight ESC Resource Re-Mapping
  1. Check flight controller orientation
    1. Plug in the drone’s flight controller to Betaflight and go to the Setup tab.
    2. While still connected to the USB, move the drone around the three axis (pitch, yaw, and roll) and ensure the picture of the drone in the Setup tab in Betaflight is moving in the same manner.
    3. If it is not moving in the same manner, go to the Configuration tab and change the settings in the “Board and Sensor Alignment” section.
  2. Transmitter connection
    1. Ensure receiver in Betaflight recognizes transmitter movements as expected by going to the Receiver tab and moving around the transmitter sticks. Sometimes, the receiver is not powered by the USB, so you will need to plug in the battery (AFTER removing props) to get power to the receiver.
    2. Check channel endpoints. This will ensure that the flight controller is detecting the entire range of your transmitter sticks.
  1. Failsafe check
    1. Ensure failsafe is set in Betaflight (this is on by default) and your transmitter has failsafe set (this is not set by default). In general, you want your transmitter failsafe to be set to “no pulses” or “cut”. As soon as a failsafe is detected, the drone will stop the motors and the drone should drop, relatively, straight down.
    2. One way to check failsafe once all other setup steps have been completed is to:
      1. Have props removed
      2. Plug in a battery into the drone and turn on your transmitter
      3. Arm and confirm motors are spinning
      4. Then turn off the transmitter and confirm that the drone stops its motors.
    3. Modes/switches
      1. Check the Modes tab in Betaflight to ensure your switches, including the Arm switch, is functioning as you expect it to.
    4. Prop orientation
      1. Lastly, ensure the prop orientation matches the rotation/orientation of the motors!

Following the recommended routine maintenance and care should prolong the life of your gear. Consider modifying the routine to fit your needs and situation, and your quads will thank you by keeping you flying for the months to come!

If you have any questions, leave them down in the comments below.

By | 2018-05-18T11:40:29+00:00 May 18th, 2018|Quick Tips|0 Comments

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